myopathy

EM guidemap - Myopathy and myoglobulinuria

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Introduction

General principles

● endocrine myopathy

● toxic myopathy

● periodic paralyses

● myoglobinuria

Introduction

- this short guidemap supplements the neuromuscular weakness guidemap and offers the reader supplementary information on myopathies, and a short section on myoglobulinuria

- this guidemap only consists of a few brief checklists of "causes of the different types of myopathy" that an emergency physician may encounter in clinical practice when dealing with a patient with acute/subacute muscular weakness

General principles

- a myopathy is suggested when generalized muscle weakness involves large proximal muscle groups, especially around the shoulder and proximal girdle, and when the diffuse muscle weakness is associated with normal tendon reflexes and no sensory findings

- a simple classification of myopathy:-

Hereditary

● muscular dystrophies ● congenital myopathies

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● myotonias ● channelopathies (periodic paralysis syndromes) ● metabolic myopathies ● mitochondrial myopathies

Acquired

● inflammatory myopathy ● endocrine myopathies ● drug-induced/toxic myopathies ● myopathy associated with systemic illness

- a myopathy can present with fixed weakness (muscular dystrophy, inflammatory myopathy) or episodic weakness (periodic paralysis due to a channelopathy, metabolic myopathy due to certain glycolytic pathway disorders)

- a myopathy can be acute (< 4 weeks), subacute (4 - 8 weeks) or chronic (> 8 weeks)

- channelopathies and certain metabolic myopathies can produce recurrent episodes of episodic weakness, while certain toxins (eg. cocaine) can produce a single episode of episodic weakness

- abnormal weakness after exercise suggests a channelopathy, or a metabolic or mitochondrial myopathy (mimics myasthenia gravis)

- muscle pain (myalgia) is surprisingly infrequent in many myopathies, and the presence of episodic muscle pain suggests a metabolic myopathy, while constant muscle pain suggests an inflammatory myopathy

- muscle cramps are not common in myopathic disorders, and they strongly suggest anterior horn cell disorders eg. amyotrophic lateral sclerosis, or many non-specific conditions eg. dehydration and hyponatremia, azotemia, hemodialysis, pregnancy

- muscle contractures resemble cramps, but they last longer and are usually provoked by exercise in patients with glycogenolytic enzyme defects

- myotonia is the phenomenon of impaired muscle relaxation after a forceful muscle contraction; patients complain of muscle stiffness and difficulty releasing their handgrip after a handshake

- myotonia often improves after exercise (warm-up phenomenon), in contrast to paratonia where exercise makes the myotonia worse; both myotonia and paratonia are http://www.homestead.com/emguidemaps/files/myopathy.html (2 of 13)8/20/2004 5:14:27 PM myopathy usually worse when exposed to the cold

(* paratonia suggests frontal lobe disease and is seen in association with other signs suggestive of frontal lobe disease eg. frontal gait ataxia, "gegenhalten")

- certain myopathies may produce rhabdomyolysis and myoglobulinuria, and the combination of weakness + muscle pain + discolored red urine after mild exercise, or prolonged exercise, suggests a metabolic myopathy eg. glycolytic pathway defect or fatty acid oxidation defect

(* strenuous anaerobic exercise can produce rhabdomyolysis and myoglobulinuria even in healthy people)

- muscle atrophy is a late finding in chronic progressive myopathies, and the pattern of muscle atrophy can suggest a particular myopathy eg. atrophy of the peri-scapular muscles causing scapular winging suggests fascioscapulohumeral dystrophy, selective atrophy of the quadriceps and forearm muscles suggests inclusion body myopathy

- the pattern of muscle weakness can suggest a particular myopathy

● limb girdle weakness (proximal muscle weakness) is non-specific and is seen in many hereditary and acquired myopathies ● scapuloperoneal weakness due to weakness of the peri-scapular muscles and muscles of the anterior compartment of the lower leg in association with facial muscle weakness suggests fascioscapulohumeral dystrophy, scapuloperoneal dystrophy, Emery-Dreifuss dystrophy, acid maltase deficiency and some congenital myopathies ● asymmetric weakness of of distal forearm muscles (wrist and finger flexors) + proximal lower extremities (quadriceps) is essentially pathognomonic of inclusion body myositis => produces weakness of hand grip and frequent falling ● prominent neck extensor muscle weakness (dropped head) suggests isolated neck extensor myopathy, polymyositis, dermatomyositis, inclusion body myositis, carnitine deficiency, myotonic dystrophy, or a congenital myopathy ● predominant weakness of ocular and pharyngeal muscles suggests oculopharyngeal dystrophy, while ptosis and ophthalmoplegia without prominent pharyngeal involvement suggests a motochondrial myopathy ● ptosis and facial weakness without ophthalmoplegia and pharyngeal weakness suggests myotonic dystrophy

Endocrine myopathy

Hypothyroidism

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- neuromuscular findings in hypothyroidism include proximal muscle weakness, muscle stiffness and cramping, muscle hypertrophy, slow reflexes and myoedema

(* myoedema is the phenomenon of rounding up of muscle tissue after light percussion)

- lipid-lowering drugs may exacerbate hypothyroidic myopathy

- the CK may be elevated up to 10X in hypothyroidic myopathy

Hyperthyroidism

- neuromuscular findings include proximal muscle weakness with atrophy, brisk reflexes, and bulbar weakness

- respiratory muscle weakness and respiratory failure is rare

- there may be some clinical overlap with myasthenia gravis, and medical treatement of the thyroid disease may exacerbate the myasthenia

- thyrotoxic hypokalemic paralysis is a rare phenomenon in Asian patients in their third decade

Hypoparathyroidism

- usually produces muscle tetany due to hypocalemia

- a myopathy rarely occurs

Hyperparathyroidism

- a proximal muscle weakness associated with easy fatigueability, atrophy and hyperrflexia may occur

Cushings disease

- usually produces an insidious onset of proximal muscle weakness and atrophy and myalgia

- iatrogenic steroid administration may produce a similar picture, and high-dose steroids may rarely produce quadriplegia and respiratory failure

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Toxic myopathy

- there are many causes of a toxic myopathy, and one system of classifying toxic myopathy is as follows:-

Painless myopathies

● alcohol (chronic) ● steroids ● myoglobulinuria (CNS depressants, CNS stimulants, carbon monoxide, cyanide, arsenic, snake venoms) ● hypokalemia (licorice, carbenoxolone, amphotericin B, toluene, diuretics, alcohol) ● others (chloroquine, quinacrine, pancuronium, vecuronium, amiodarone, perhexiline, colchicine, vincristine)

Painful myopathies

● D penicillamine ● procainamide ● phenytoin ● levodopa ● cimetidine ● leuprolide ● propylthiouracil ● zidovudine ● germanium ● others (alcohol, clofibrate, gemfibrizol, lovastatin, simvastatin, epsilon aminocaproic acid, etretinate, isotretinion, hypervitaminosis E, ipecac, emetine, organophosphates, toxic oil syndrome)

Drugs of abuse

● alcohol ● amphetamines ● cocaine ● heroin ● phencyclidine ● toluene and gasoline

- the CNS sedatives produce a painless myoglobulinuric myopathy due to over-sedation and immmobilization resulting in pressure necrosis

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Periodic paralysis

- there are many different types based on varying genetic abnormalities of the sodium, calcium or potassium channel

- this basic outline is a summary of some of the major types, which are most likely to produce severe episodes of muscle weakness

Hypokalemic periodic paralysis

- due to a disorder of voltage-gated calcium (Ca2+) channel gene, CACNL1A3, chromosome 1q

- often runs in families (2/3 of cases)

- develops in early childhood and always < 30 years of age (otherwise consider thyrotoxic hypokalemic periodic paralysis or secondary hypokalemia-induced paralysis)

- attacks often occur during sleep in the early morning hours => on awakening the patient may have profound weakness and be unable to get out of bed

- attacks may be precipitated by a "trigger" on the preceding day - triggers include cold, strenuous exercise followed by rest, large carbohydrate meal

- proximal limbs and truncal musculature weak, cranial nerves and respiratory muscles usually spared

- attack lasts hours-days; usually 3 - 6 hours

- the serum potassium is usually low during attacks; however, the serum potassium may be normal

- over the years, in the absence of treatment, weakness may develop between attacks

- treatment in the ED should be oral potassium; avoiding IV potassium or IV glucose solutions

Thyrotoxic hypokalemic paralysis

- male predominance (80 - 95%)

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- onset 20 - 40 years

- proximal weakness > distal weakness, legs > arms; weakness may selectively involve exercised muscles

- severe attacks may involve respiratory and bulbar muscles

- attacks last hours-days

- attacks often occur randomly without an obvious stimulus; attacks may be precipitated by rest after heavy exercise, a carbohydrate challenge and muscle cooling; attacks may be aborted by mild exercise

- underlying thyrotoxicosis, which may be sub-clinical (diagnosed by low TSH and increased radioiodine uptake by thyroid), is present; sporadic condition and not familial

- the serum potassium is usually low during attacks

- treatment of attacks includes propanolol +/- small amounts of oral potassium + treatment of thyrotoxicosis (IV potassium should not be used because the hypokalmia is a redistributive hypokalemia and hyperkalemia may occur if excess potassium is administered IV)

Andersen's syndrome

- onset 2 - 18 years

- presents with cardiac arrhythmia (bidirectional tachycardia) and prolonged QT interval due to kypokalemia, and/or episodic muscle weakness (1 hour - few days)

- associated clinical findings include hypertelorism, hypoplastic mandible, low-set ears, malar hypoplasia, short stature, scoliosis, lateral or medial curvacture of a finger or toe

- serum potassium may be low, normal or high during attacks, and the attacks can be precipitated by exercise or potassium loading (in contrast to hypokalemic periodic paralysis, where potassium loading improves strength)

- raising serum potassium may precipitate weakness, but normalize the ECG; while lowering serum potassium may improve strength but worsen the ECG abnormalities

- permanent weakness occasionally occurs

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- no known optimum treatment

Hyperkalemic periodic paralysis

- onset during infancy and childhood (< 10 years) with no sex predisposition

- dues to a sodium channel gene abnormality

- attacks of weakness occur during periods of hyperkalemia (which defines the disease)

- attacks may be precipitated by potassium loading, exercise, fasting, cold temperatures and emotional stress; attacks last 1 - 3 hours and rarely days; attacks occur more frequently than they occur in hypokalemic periodic paralysis and are usually less severe and shorter in duration

- serum potassium level may actually be normal, or even low, after the onset of an attack (which does not define the disease)

- weakness usually involves proximal muscles, and occasionally only the exercising muscles

- weakness may be relieved by carbohydrate loading (opposite of hypokaleic periodic paralysis) and mild exercise

- patients may have evidence of myotonia (inability to relax muscles) or paramyotonia (muscle stiffness worsened by exercise and cold) between attacks

- permanent weakness may eventually develop if not treated prophylactically between attacks (responds to acetazolamide)

Myoglobinuria

Myoglobinuria refers to an abnormal pathologic state in which an excessive amount of myoglobin is found in the urine causing the urine to appear coca-cola colored, usually in association with severe muscle injury and a clinical picture of muscle weakness +/- myalgias +/- muscle tenderness and swelling

- the myoglobinuria usually reflects an underlying state of rhabdomyolysis and associated laboratory abnormalities may include hyperkalemia, hyperphosphatemia, hypocalcemia and hyperuricemia, and laboratory evidence of secondary renal failure (increased serum

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(* hemoglobinuria may also cause a brownish urine and be secondary to hematuria or intravascular hemolysis - in hematuria red cells are present in the urine + serum is clear, while in IV hemolysis the urine contains no red cells, the serum is pink and the serum CK is negative)

- the serum CK is characteristically elevated (often > 10 - 100x normal)

Causes of myoglobinuria

Hereditary causes of myoglobinuria

- metabolic myopathies with identified enzyme defects and non-identified defects, and includes disorders of glycolysis or glycogenolysis or fatty acid oxidation or mitochondrial oxidation defects

- myoglobinuria may occur following exercise, infection, fasting, or exposure to an offending drug

Disorders of glycolysis or glycogenolysis

- an attack of myoglobinuria may be the presenting complaint in patients with glycogen storage myopathies, and the disorders are characterized by recurrent episodes of muscle pain, muscle weakness and muscle cramps +/- myoglobinuria

- the attacks may be precipitated by intense exercise, especially under anaerobic conditions, and the muscle symptoms may be localized to the exercising muscles

- the disorder usually presents in childood, and the patients often have a family history, a mild baseline elevation of CK and low-level myoglobinuria

- the disorders are all characterized by abnormal glycogen accumulation in muscle biopsy specimens

- specific identified enzyme defects include phosphorylase (McArdle's disease), phosphofructokinase, phosphoglycerate kinase, phosphoglycerate mutase, lactate dehydrogenase, phosphorylase b kinase and debrancher

Disorders of fatty acid oxidation

http://www.homestead.com/emguidemaps/files/myopathy.html (9 of 13)8/20/2004 5:14:27 PM myopathy - characterized by recurrent attacks of myoglobinuria and exercise-induced myalgia that occur during prolonged activity, particularly when glycogen stores have been depleted and the exercising muscle is dependent on fatty acid fuel

- cold temperatures, fever and infection may also precipitate attacks

- seven specific fatty acid oxidation defects have been identified - carnitine palmitoyltransferase II deficiency, long chain acyl-conenzyme A dehydrogenase deficiency, medium chain acyl-coenzyme A dehydrogenase deficiency, short chain L-3 hydroxyacyl-CoA dehydrogenase deficiency, very long chain acyl-CoA dehydrogenase deficiency, trifunctional protein deficiency and medium chain 3-ketoacyl-CoAthiolase deficiency

- carnitine palmityl transferase deficiency is the most common hereditary metabolic cause of recurrent myoglobinuria => patients presents in adolescence with exercise intolerance (muscle stiffness and myalgia and muscle weakness without warning muscle cramps) - which can also be provked by a prolonged fast, stress, infection, cold or infection

Mitochondrial and respiratory chain disorders

- also produce recurrent attacks of myoglobinuria

- deficiency of aconitase and succinate dehydrogenase produce exercise intolerance and myoglobinuria

Dystrophinopathies

- include Duchenne's muscular dystrophy, Becker's, fascioscapulohumeral dystrophy and myotonic dystrophies

- these patients may have a low baseline level of myoglobinuria

Malignant hyperpyrexia

- characterized by attacks of myoglobinuria, hyperpyrexia, muscle rigidity and lacticacidosis

- prdisposing conditions include central and multicore myopathies, myotonic disorders, Duchenne's, Becker's and congenital muscular dystrophies

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Acquired causes of myoglobinuria

Extreme physical exertion

- increased risk associated with high intensity exercise of prolonged duration + high ambient temperature + impaired heat dissipation (humidity, anticholinergic drugs) + lack of training (training is exercise-specific and well-trained athletes can develop myoglobinuria during high intensity novel physical activities)

Vigorous involuntary activities can also induce myoglobinuria:-

● status epilepticus ● severe myoclonus ● severe dystonia ● tetanus ● mania

Heat stroke

Thyroid storm

Neuroleptic malignant syndrome

Prolonged exposure to extreme cold

Hypokalemia-induced

- secondary to diuretics, renal tubular acidosis, amphotericin B, licorice, alcoholism ... etc.

Chronic hypophosphatemia

Hypernatremia

Hyperosmolar ketotic states

Diabetic ketoacidosis

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High voltage electrical burns and lightning injury

Prolonged immobilization

Arterial insufficiency and acute limb ischemia

Compartment syndromes

Infections

Viruses

● influenza A and B ● herpes viruses ● Cox-Sackie virus ● EBV, enteroviruses ● HIV

Bacteria and rickettsia

● legionella ● streptococcus ● tularemia ● clostridium ● hemophilus influenza ● Q fever ● typhoid fever ● E coli

Parasites

● plasmodium

Inflammatory myositis

● polymyositis ● dermatomyositis

Drug-induced myopathy

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● lipid-lowering agents (statins, clofibrate and gemfibrizol) ● agents that cause hypokalemia (diuretics, theophylline, amphotericin B) ● lithium ● succinylcholine ● antibiotics (trimethoprim, isoniazid) ● anticonvulsants (valproic acid, lamotrigine, prolonged propofol infusion) ● vasopressin ● colchicine, episilon aminocaproic acid, high dose alfa-interferon ● illicit drugs (cocaine, heroin, phencyclidine, amphetamines)

Biological toxins

● snake venom ● Africanized bees, honeybees, wasps, hornets, red-backed spiders ● consumption of amanita phalloides mushrooms, blue humphead parrotfish, quail that have eaten water hemlock seeds, and Haff disease from consumption of turbot fish from lakes in Sweden and eastern Europe or buffalo fish in the USA

Non-biological toxins

● carbon monoxide ● inhalation of volative solvents (toluene, gasoline, other hydrocarbons in paint thinners) ● strychnine

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemaps - Neuromuscular weakness

Click on any of the headings or subheadings to navigate to the relevant section of the guidemap

Introduction

General principles

● bilateral weakness of all 4 limbs (both arms and both legs)

● differentiation between UMN and LMN

● bilateral weakness of the upper and lower limbs table

● anatomic localization of a tetraparesis

● bilateral weakness of the legs

● anatomic localization of a paraparesis

● asymmetric or focal muscle weakness

● anatomic localization of a hemiparesis

● episodic weakness

Clinical decision-making in an ED setting

● clinical features of some diseases causing an ascending paralysis

● clinical clue table - some causes of rapidly progressive neuromuscular weakness

● diagnostic testing in acute neuromuscular weakness

Appendix

● medical research council rating of muscle strength

● practical muscle strength testing

● detailed muscle strength testing - upper limb

● detailed muscle strength testing - lower limb

● muscle stretch reflexes

● drugs precipitating or aggravating neuromuscular weakness

Introduction

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- this guidemap is primarily focused on problem-solving neuromuscular disorders causing rapidly progressive weakness that will cause the patient to present to an ED with a history of acute weakness, and it does not discuss neuromuscular diseases causing chronic, slowly progressive weakness

- neuromuscular weakness can be due to UMN or LMN diseases, neuromuscular junction disorders, or muscle diseases; this guidemap mainly offers a conceptual approach to neuromuscular weakness so that an emergency physician can narrow the differential diagnoses to a likely set of possible diagnoses - on the basis of fundamental pathophysiological principles (myopathy vs neuropathy vs neuromuscular transmission disorder vs motor neuron)

- this guidemap is linked to the myopathy and myoglobinuria sub-guidemap, which provides more problem-solving information on myopathies and myoglobinuria

General principles

- the symptom of "weakness" is a common, and often vague, complaint and an emergency physician must first differentiate true neuromuscular weakness from diseases that can produce non-specific weakness and/or fatigue eg. anemia, acute blood loss, cardiopulmonary diseases causing hypoxia, single or multiple end organ failure (heart failure, renal failure, hepatic failure), metabolic imbalance, endocrine dysfunction, connective tissue diseases, fibromyalgia, chronic fatigue syndrome, and psychological disorders

- the most useful clues suggesting true neuromuscular weakness come from a targeted history that specifically inquires about particular muscular activities that the patient cannot easily accomplish

- difficulty climbing stairs, or difficulty getting out of a chair, or difficulty getting up from a squatting position (eg. after toileting) without using the arms suggests proximal lower limb (hip girdle) weakness, while difficulty using the arms when performing above the shoulder level activities (eg. combing one's hair, lifting heavy objects off high shelves) suggests proximal upper limb (shoulder girdle) weakness; truncal weakness is suggested by an inability to sit up in bed without using the arms; distal weakness of the upper limbs is suggested by difficulties with wrist and hand movements and fine motor control (eg. tying shoelaces, doing up buttons, using writing and eating utensils, unscrewing screw-on jar lids)

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Pattern of muscle weakness - likely source of weakness Symptoms Likely source of weakness Slurred-nasal speech Bulbar muscles Drooling Nasal regurgitation of liquids Difficulty whistling, smiling Difficulty swallowing Diplopia Extraocular muscles Ptosis Trouble reaching for high shelves Proximal upper limb muscles Difficulty shaving, combing hair, using hair dryer Difficulty opening jars, doors, using keys or Distal upper limb muscles silverware Difficulty rising from chairs and sofas Proximal lower limb weakness Difficulty getting out of a car, bath or off a toilet Difficulty climbing stairs Tripping when walking Distal lower limb weakness

- after first establishing the presence of muscle weakness, it is useful to determine whether the weakness is bilateral and symmetric, or whether the weakness is asymmetric or focal

Bilateral weakness of all 4 limbs (both arms and both legs)

- bilateral weakness involving all 4 limbs is usually due to a myopathy, a neuromuscular junction disorder, a neuropathy, and rarely due to an upper-mid cervical myelopathy or brainstem or cerebral pathology

- the distribution of weakness can suggest a particular pathophysiology

- proximal muscle weakness suggests a myopathy rather than a neuropathy, which usually causes distal muscular weakness => distal muscle weakness can involve the hands (eg. difficulty with fine muscle movements of the hands when handling eating utensils, or when attempting to unscrew screw-on jar lids) and/or the feet (tripping over the curb or scuffing the feet when walking secondary to foot drop)

Distal weakness of both the upper and lower limbs is near-pathognomonic of a peripheral neuropathy http://www.homestead.com/emguidemaps/files/nmweakness.html (3 of 35)8/20/2004 5:14:35 PM nmweakness

- another clue that suggests a myopathy is that the muscle weakness is usually global and it involves both the upper and lower limbs +/- trunk musculature, with major weakness of large muscle groups rather than small muscle groups

- a myopathy tends not to affect the bulbar muscles, and involvement of the motor cranial nerves (external ocular muscle weakness => diplopia, levator palpebrae superioris weakness => ptosis, face paralysis => face drooping and inability to grimace , pharyngeal muscle paralysis => dysphagia, tongue paralysis => dysarthria) in association with bilateral generalized muscle weakness suggests a neuromuscular junction disorder eg. myasthenia gravis or botulism

- an acute myopathy does not usually produce muscle atrophy, which is late sign of severe or progressive muscle disease and the degree of atrophy often parallels the extent of the progressive myopathy; acute muscle atrophy developing within days/weeks of the onset of weakness usually suggests a LMN (anterior horn cell or nerve root or peripheral nerve) lesion

- an acute myopathy may be associated with muscle tenderness +/- muscle swelling; muscle tenderness suggests an inflammatory or infectious myopathy (eg. polymyositis); muscle tenderness + swelling suggests trichinosis, clostridial myositis or other bacterial myositis; however, many myopathies produce profound muscle weakness without any muscle tenderness

(* a history of recurrent episodes of episodic muscle weakness accompanied by myoglobinuria suggests a genetic metabolic myopathy, and further metabolic investigations are warranted)

- tendon reflexes are retained in myopathic disorders until very late in the disease course, and early loss of deep tendon reflexes suggests a neuropathy

Normal reflexes in the upper limbs and absent reflexes in the lower limbs suggests a thoracic or lumbar spinal cord lesion

- a myopathy does not cause sensory loss, and any sensory deficit associated with motor weakness implies either a mixed sensorimotor peripheral neuropathy, a myelopathy or a brainstem/cerebral lesion

Key clinical features used to localize a neuromuscular disorder

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Myopathy

● predilection for neck, limb girdle and proximal muscles ● occasional respiratory muscle involvement ● possible risk of myoglobulinuria ● no sensory loss ● normal tendon reflexes (early stage)

Neuromuscular junction

● cranial, limb girdle and proximal muscles ● may affect respiratory muscles ● no sensory loss ● autonomic symptoms present if pre-synaptic ● fatigueability when post-synaptic, post-exercise increase in strength when pre-synaptic

Neuropathy

● weakness and sensory signs ● may have associated autonomic signs ● may involve cranial nerves ● tendon reflexes decreased or absent

Motor neuron

● predominantly motor signs ● occasional sensory symptoms ● often asymmetric ● tendon reflexes may be increased if amyotrophic lateral sclerosis

- muscle tone is reduced in myopathic diseases and LMN lesions (eg. peripheral neuropathy), and increased muscle tone suggests an UMN lesion (spasticity)

(* spasticity is common in UMN lesions and the increased muscle tone is found in the flexor muscle muscles of the upper limbs and extensor muscles of the lower limb; by contrast, muscle rigidity usually involves both the flexor + extensor muscle groups of all the limbs and it may have a lead-pipe rigidity pattern eg. neuroleptic malignant syndrome, or a varying cogwheel rigidity pattern if there is a superimposed tremor eg.

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- bilateral muscle weakness involving all 4 limbs (tetraparesis) that is due to nervous system disease - and not muscle disease - can either be an UMN weakness (cerebral motor cortex pathology, corticospinal tract pathology in the brainstem or cervical spinal cord pathology) or LMN weakness (anterior horn cell, nerve root, or peripheral nerve)

- UMN weakness, if well-established (subacute or chronic), is associated with:-

● spasticity ● hyperreflexia ● clonus ● extensor plantar response

(* however, acute UMN lesions often produce flaccidity, hypotonia and absent Babinski reponses - mimicing a LMN lesion)

- LMN weakness is associated with:-

● hypotonia ● hyporeflexia ● fasiculations ● absent extensor plantar response

A general rule is that if the weakness only involves an entire limb (monoplegia), both lower limbs (paraplegia), an upper and lower limb on the same side of the body (hemiplegia) or all 4 limbs (tetraplegia) - the causative lesion is most likely an UMN lesion in the CNS

LMN lesions usually involve a segment of a limb in a segmental or peripheral nerve pattern

Differentiation between UMN and LMN pathology Clinical sign UMN LMN Region Monoplegia, paraplegia, Segmental - part of a hemiplegia, tetraplegia limb Muscle tone Increased (not early on) Decreased Atrophy Minimal or absent Present (not early on)

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Fasiculations Absent May be present Reflexes Hyperreflexia (not early Hyporeflexic on) Extensor plantar Present (not early on) Absent response

- an UMN lesion causing a UMN-type tetraparesis produces associated clinical signs depending on the site of pathology => see table

Bilateral weakness of the upper and lower limbs Myopathy Neuropathy Neuromuscular

junction Distribution of Proximal Distal (initially) General weakness Ocular and bulbar Rare Infrequent Common muscle weakness Muscle pain and/ +/- - - or tenderness Muscle atrophy Late Early - Reflexes Preserved - Absent - early Present early Absent- late Sensory deficit Absent May be present Absent

Anatomic localization of a tetraparesis - due to UMN pathology Location of lesion Pattern of neurological signs Bilateral cerebral hemipsheres Tetraparesis, spastic dysarthria, dysphagia with hyperactive jaw jerks (pseudobulbar palsy), decorticate posturing (large acute lesions) Midbrain Tetraparesis, coma, mid-sized poorly reactive pupils, decerebrate posturing

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Basis pontis Tetraparesis, "locked in "syndrome, paralysis of horizontal gaze, paralysis of jaw and face and pharnyx and tongue muscles, preservation of consciousness and blinking and vertical eye movements Cervicomedulllary junction Tetraparesis +/- involvement of pharnyx and tongue High cervical Tetraparesis, no cranial nerve palsies, no hyperreflexic jaw jerk Mid cervical Tetraparesis + preserved shoulder movements

Bilateral weakness of the legs

- usually due to UMN pathology (cerebral motor cortex - bilateral, corticospinal pathways in the lower spinal cord) or LMN pathology (cauda equina pathology, lumbosacral plexus, peripheral nerves)

- localisation of UMN lesions is critically dependent on determining whether there is a sensory level, which suggests a spinal cord lesion rather than a cerebral lesion

Anatomic localization of a paraparesis due to UMN pathology Location of lesion Pattern of neurological signs Bilateral medial cerebral hemispheres Spastic paraparesis with no sensory (parasagittal lesion eg. meningioma) level Thoracic spinal cord Spastic paraparesis with thoracic sensory level and spastic bladder (* subacute or chronic) Lumbar spinal cord Spastic paraparesis with lumbar level and spastic bladder (* subacute or chronic)

(* subacute or chronic spinal cord lesions produce spasticity, hyperreflexia and a spastic bladder, while acute spinal cord lesions may produce hypotonia and hyporeflexia and a flaccid bladder)

- a cauda equina lesion is usually associated with asymmetric LMN signs involving the lower lumbar and sacral nerve roots (weakness, hypotonia, hyporeflexia, and absent

http://www.homestead.com/emguidemaps/files/nmweakness.html (8 of 35)8/20/2004 5:14:35 PM nmweakness extensor plantar reflexes) leading to decreased strength of the glutei muscles, hamstrings, gastrocnemius and soleus muscles + saddle anesthesia +/- a flaccid bladder

- a polyneuropathy may start in the lower limbs and eventually ascend to involve the trunk and upper limb muscles eg. Guillain-Barre syndrome => it may therefore only produce bilateral lower limb weakness during the early stage of the disease

A polyneuropathy involving the lower limbs may produce a paraplegia, mimicing ACUTE transverse myelitis (or another acute transverse myelopathy), which is suggested by the presence of a sensory level + urinary retention in addition to the paraplegia

- certain myopathies preferentially cause lower limb weakness eg. chronic alcoholic myopathy

Asymmetric or focal muscle weakness

- asymmetric muscle weakness can be due to an unilateral UMN lesion causing a hemiparesis, or be due to an asymmetric LMN lesion eg. poliomyelitis

- focal weakness can be isolated (single anatomic site) or multifocal (multiple non- contiguous anatomic sites)

- multifocal weakness suggests multiple sclerosis or mononeuritis multiplex (usually due to DM, or vasculitis [eg. SLE, polyarteritis nodosa, rheumatoid arthritis], or sarcoidosis, or tuberculosis or Waldenstrom's macroglobulinemia)

- isolated focal weakness can be due to disease of the cerebrum, brainstem, spinal cord, nerve root, nerve plexus, or peripheral nerve

- localization of UMN diseases causing a hemiparesis depends on the associated clinical signs

Anatomic localization of a hemiparesis - due to UMN pathology Location of lesion Pattern of neurological signs

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Cerebral cortex Contralateral arm affected more than leg or face +/- aphasia, apraxia, contralateral homonymous hemianopia (left hemisphere) +/- contralateral homonymous hemianopia, inattention to left half of body, constructional apraxia (right hemisphere) Internal capsule Contralateral arm equal to leg, face may be spared No sensory loss or aphasia Brain stem Contralateral arm equal to leg plus ipsilateral cranial nerve palsy Midbrain Third nerve palsy (Weber syndrome) Pons Sixth and seventh nerve palsy + ipsilateral gaze palsy (Foville syndrome) Medulla Twelth nerve palsy Cervical hemi-cord Ipsilateral weakness of arm and leg; ipsilteral loss of proprioception and vibration sensation; contralateral loss of pain and temperature sensation (Brown-Sequard syndrome)

Episodic weakness

- there are many causes of intermittent or fleeting muscle weakness

- a TIA is a common cause of episodic UMN weakness

- other less common diseases mimicing a TIA include partial epileptic seizures, Todd's paralysis following a generalized convulsive seizure, and hemiplegic migraine

- rare causes of episodic muscle weakness include periodic paralysis syndromes

- certain diseases causing episodic muscle weakness may result in drop attacks (eg. catalepsy, sleep paralysis associated with hypnogogic hallucinations, Arnold-Chiari malformations or unstable alanto-axial joints compressing the cervicomedullary junction) => see the "drop attacks" section of the gait disorders, drop attacks and frequent falls guidemap for further details

Clinical decision-making in an ED setting

http://www.homestead.com/emguidemaps/files/nmweakness.html (10 of 35)8/20/2004 5:14:35 PM nmweakness - an emergency physician should always be alert to any alterations in the vital signs (tachycardia, hypotension, hyperpyrexia) that may suggest a systemic disease causing "weakness", and some examples include:-

● Addison's disease ● acute myocardial infarction ● blood loss and hypovolemic shock ● septic shock or toxic shock syndrome

- if the vital signs are normal, and the clinical presentation suggests a neuromuscular disorder causing generalized muscle weakness (rather than non-specific weakness), then an emergency physician needs to perform a thorough neurological examination in order to accuratedly differentiate the various sub-categories of neuromuscular weakness (myopathy, NM junction disorder, neuropathy, UMN or LMN pathology)

- essential neurological examination elements include an evaluation of:-

● motor strength (above and below the foramen magnum) ● motor tone ● tendon reflexes ● fasiculations +/- motor atrophy ● sensory deficits ● cranial nerve deficits

- is should be possible, after performing a targeted neurological examination, to have a good idea whether the patient has a myopathy, neuropathy, UMN lesion or a neuromuscular transmission disorder as the likely cause of the acute neuromuscular weakness

- combining that pathophysiological knowledge with common-sense knowledge regarding the frequency of certain diseases, it should be possible to make a sensible tentative diagnosis

- for example, a young patient with an ascending paralysis (over a few days), who has presenting sensory dysesthesias and paresthesias, but no sensory loss + absent/ reduced deep tendon reflexes, is likely to have acute demyelinating inflammatory polyradiculopathy (Guillain-Barre syndrome)

- when faced with that presentation, an emergency physician should always ensure that there is no sensory level, which suggests a transverse myelopathy; that there there are no ticks hidden in the scalp hair, which suggests tick paralysis; and that fever and meningeal signs are absent, which suggests acute poliomyelitis

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Clinical features of some diseases causing an ascending paralysis Clinical feature Tick ADIP Spinal cord Poliomyelitis paralysis lesion Rate of Hours to days Days to Abrupt or gradual Days to weeks progession weeks Tendon reflexes Absent Absent Variable - normal Absent reflexes above the lesion and absent reflexes (acute) or hyperactive reflexes (subacute) below the lesion Extensor plantar Absent Absent Absent (acute) Absent response Present (subacute) Sensory signs None Rare Present (sensory Absent (distal level - below the limbs) lesion) Meningeal signs Absent Rare Absent-rare Present or fever

- if the patient presents with oculo-bulbar paralysis +/- descending paralysis, then one should first think of myasthenia gravis and botulism; the presence of pupillary paralysis + other autonomic signs suggests botulism; and a history of episodic weakness and a fatigueability phenomenon suggests myasthenia gravis; associated ataxia should make one think of the Miller-Fisher variant of ADIP

- if the patient presents with an acute myopathic presentation (proximal muscle weakness + no sensory findings + normal reflexes + no bladder/bowel dysfunction), then one should first determine whether the myopathy is painless or painful

- acute painless myopathy is most likely due to one of the periodic paralysis syndromes, an electrolyte disorder (eg. hypokalemia or hypercalcemia) or a toxic myopathy (drugs or toxins)

- acute painful myopathy is most likely due to a toxic myopathy (alcohol, certain drugs

http://www.homestead.com/emguidemaps/files/nmweakness.html (12 of 35)8/20/2004 5:14:35 PM nmweakness or toxins) or an inflammatory myopathy (eg. polymyositis) or infectious myositis (eg. trichinosis, toxoplasmosis, viral or bacterial myositis)

(* the presence of muscle tenderness + swelling +/- crepitus+/- myoglobinuria strongly suggests an infectious or necrotizing myositis)

- occasionally, a patient may present to the ED with rapidly progressive muscle weakness that is so profound, that it may be difficult for the clinician to clearly differentiate a neuropathy from a myopathy (or other cause of profound muscle weakness), because of the patient's inability to speak or fully cooperate during a neurological examination

If the patient appears to have profound muscle weakness of acute onset and cannot readily speak, an emergency physician should have a low threshold for prophylactic intubation and mechanical ventilation

- clinical clues that suggest respiratory failure secondary to muscle weakness, or a need for intubation include:-

● weak, nasal-palatal voice ● disproportionate tachypnea or bradypnea ● poor chest wall excursions during breathing, and/or paradoxical respiratory movements, and/or marked respiratory "difficulty" ● dysphonia and/or noisy respiration ● poor air entry assessed by chest auscultation (decreased/absent breath sounds) ● vital capacity < 1 litre (adult) or < 15ml/kg (pediatric), or falling VC over 4 - 6 hours ● decreased minute ventilation or poor inspiratory force (maximum inspiratory pressure < 20 cm.water) ● altered LOC secondary to hypoxia or hypercarbia ● history of previous myasthenic crises requiring intubation ● marked increase in respiratory secretions suggesting a cholinergic crises due to over-medication of myasthenia gravis, organosphophate poisoning or nerve gas (sarin) poisoning ● oropharyngeal weakness with high risk of pulmonary aspiration

- there are no "fixed" clinical criteria mandating prophylactic intubation, and clinicians should use judicious clinical judgment and meticulous, continued observation of the patient during the initial clinical evaluation stage to avoid being caught off guard

(* an ABG showing hypercarbia is a definite indication for intubation and mechanical ventilation, but clinicians should not wait for laboratory evidence of alveolar hypoventilation before considering prophylactic intubation; if a patient can take a

http://www.homestead.com/emguidemaps/files/nmweakness.html (13 of 35)8/20/2004 5:14:35 PM nmweakness maximal inspiration and then count up to 25, the FVC is probably about 2 litres - while an ability to slowly count to 10 suggests a probable FVC of 1 litre)

- if the patient has profound bilateral muscle weakness of rapidly progressive onset, the following neuromuscular conditions should be considered in the differential diagnoses

Muscle disorders

● myoglobinuric myopathy ● hypokalemic paralysis ● toxic myopathy ● dermatomyositis and polymyositis ● genetically-determined disorders (X-lined dystrophies, myotonic dystrophy, acid maltase deficiency, mitochondrial myopathy)

Neuromuscular junction disorders

● myasthenia gravis ● botulism ● Lambert-Eaton myasthenic syndrome (LEMS) ● hypermagnesemia

Peripheral nerve disorders

● acute inflammatory demyelinating polyradiculopathy (Guillain-Barre syndrome) ● tick paralysis ● diptheritic neuropathy ● porphyric neuropathy ● arsenic neuropathy ● shellfish poisoning ● hypophosphatemia

Motor neuron disorders

● amyotrophic lateral sclerosis ● poliomyelitis

Spinal cord disorders

● transverse myelitis ● spinal cord infarction ● spinal cord compression syndrome http://www.homestead.com/emguidemaps/files/nmweakness.html (14 of 35)8/20/2004 5:14:35 PM nmweakness

UMN tetraparesis

● suggested by associated clinical findings => see table

- if the diagnosis is not readily apparent, then the history should focus on obtaining more information from any clinical clues that may suggest a particular diagnosis

Is there a pre-existing neuromuscular disorder or has the condition arisen de novo?

- several inherited neuromuscular disorders may undergo rapid progression in their final stages and produce respiratory failure (X-linked dystrophies, acid maltase deficiency), while diseases such as myasthenia gravis may produce recurrent episodes of profound weakness in the presence of infection, stress or precipitating drugs

- prior episodes of painless weakness suggest familial periodic paralysis; recurrent attacks of exercise intolerance [proximal muscle weakness + muscle cramping and muscle tenderness + myoglobulinuria after performing physical exercise] suggest an inborn error of glycogen metabolism (after a short bout of heavy exercise) or lipid metabolism (after a bout of prolonged mild-to-moderate exercise or exercise in a relatively fasted state)

Is there a history of an underlying malignancy?

- an underlying malignancy suggests the possibility of LEMS, or paraneoplastic neuropathy, or chemotherapeutic drug-induced myopathy (eg. cyclosporin)

Is there any underlying systemic disease?

- a myopathy may be due to hypothyroidism, hyperthyroidism, Cushing's disease, dermatomyositis, polymyositis

- a polyneuropathy may be due to rheumatoid arthritis, systemic lupus erythematosis, polyarteritis nodosa or cryoglobulinemia

What prescription or non-prescription drugs is the patient taking?

- certain drugs may induce myotoxicity eg. cholesterol-lowering agents, colchicine, choloroquine, cyclosporine and L-tryptophan (see table for a more complete list)

- recent use of oral contraceptives or anti-convulsants suggest the possibility of acute intermittent porphyria

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- excessive use of diuretics may induce hypokalemia and secondary hypokalemia-induced muscle weakness

- magnesium-antacid overuse in the presence of renal failure may produce hypermagnesemic weakness, or precipitate an attack of myasthenia gravis in vulnerable patients

- high-dose steroids can induce an acute steroid-induced myopathy - especially if the patient is immobile, has concurrent sepsis or is receiving neuromuscular blocking drugs

What is the dietary and exercise profile of the last 48 hours?

- recent marine shellfish consumption suggests shellfish poisoning

- recent consumption of home-canned food suggest botulism

- recent consumption of undercooked pork or game (wild boar, bear, horse) suggests trichinosis

- a large carbohydrate meal following a period of rest after heavy exercise may induce periodic paralysis

- sudden weakness following a large glucose load in a malnourished patient suggests the possibility of acute hypophosphatemic paralysis

- a bout of heavy alcohol consumption may induce an acute alcoholic myositis, and severe cases may develop rhabdomyolysis (history of "coca-cola" coloured urine); alcoholics are also prone to develop acute hypokalemic alcoholic myopathy due to severe underlying hypokalemia, or hyphosphatemic paralysis following a sudden large glucose load

Was there potential exposure to tick bite, snake bite, or a neurotoxin?

- inquire about occupational exposures (volatile solvents such as carbon tetrachloride or toluene, or arsenic used in lead and copper smelting) or recreational exposures to potential neurotoxins (volatile hexacarbon solvents causing sensorimotor neuropathy eg. glue sniffing - teenagers "huffing" from a paper bag)

- a recent woodland exposure suggests the possibility of tick paralysis

- farm exposure to pesticides containing organosphosphates suggests the possibility of a polyneuropathy (predominantly motor polyneuropathy 1 - 3 weeks after acute exposure http://www.homestead.com/emguidemaps/files/nmweakness.html (16 of 35)8/20/2004 5:14:35 PM nmweakness mainly affecting the legs => upper limbs after a few days)

In addition to weakness, are there sensory or autonomic symptoms?

- bizarre sensory symptoms suggest shellfish poisoning

- sensory paresthesias suggest a neuropathy or myelopathy

- a painful band of paresthesia around the trunk suggests the locality of an acute myelopathy eg. transverse myelitis

- prominent autonomic symptoms are seen in botulism, organophosphate poisoning and some polyneuropathies

First think of common neuromuscular disorders --- acute demyelinating inflammatory polyradiculopathy (Guillan-Barre syndrome) is the most common cause of acute generalized muscle weakness; other acute NM diseases that should initially be considered include myasthenia gravis, botulism, tick paralysis, periodic paralysis, toxic myopathies, and spinal cord disorders

- if the diagnosis is not readily apparent, the following clinical clue table offers an emergency physician a memory-jogging checklist of some causes of rapildy progressive neuromuscular weakness and their associated clinical findings

(* some of these diseases produce chronic neuromuscular weakness, and they may only produce rapidly progressive weakness under certain circumstances, or as an end-stage phenomenon; some of the listed myopathies are rare congenital disorders that occur very infrequently)

Muscle disorders Myoglobinuric myopathy

● severe limb girdle and proximal muscle weakness ● muscle swelling, aches and pains ● markedly elevated serum CK and myoglobulinuria ● see the myopathy and myoglobulinuria guidemap for further details

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Periodic paralysis

● many different variants ● often presents with disproportionate proximal muscle weakness of the trunk and lower limbs ● patients with hypokalemic periodic paralysis tend not to develop respiratory failure ● history of awakening with early am weakness, often preceded by history of heavy exercise followed by rest and/or a heavy meal the day before presentation ● weakness lasts hours to days ● a specific hypokalemic variant seen in young adult oriental patients with occult thyrotoxicosis ● see the myopathy and myoglobinuria guidemap for further details

Toxic myopathy

● proximal and limb girdle weakness ● muscle cramps and muscle tenderness ● often markedly elevated serum CK ● alcoholic patients may develop acute alcoholic mysositis secondary to binge drinking, or hypokalemic-induced or hypophosphatemic-induced paralysis ● chronic abusers of volatile solvents (eg. toluene or hobby glues) may develop severe symmetric muscle weakness in association with peripheral neuropathy, spasticity, ataxia and dementia; the weakness is associated with hypokalemia and elevated serum CK +/- rhabdomyolysis ● drugs-of-abuse (cocaine, phencyclidine, heroin and amphetamines) may also produce a toxic myopathy and rhabdomyolysis ● diuretics, licorice, carbenoxolone, amphotericin B can produce an acute hypokalemic-induced myopathy ● certain prescription drugs can produce a painful toxic myositis (penicillamine, procainamide, phenytoin, levodopa, cimetidine, leuprolide, propylthiouracil) ● cholesterol-lowering agents (gemfibrizol, clofibrate, lovastatin, simvastatin) may also produce an acute toxic myopathy, especially if multiple agents are taken together, or if taken with immunosuppressive agents (eg. cyclosporin), or in the presence of renal failure

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● carbon monoxide, arsenic, cyanide and snake venom can induce muscle necrosis and secondary myoglobinuria ● see the myopathy and myoglobulinuria guidemap for further details

Polymyositis and dermatomysositis

● severe proximal limb (legs > arms) and neck muscle weakness of gradual onset ● history of muscle pains, morning stiffness, fatigue, weight loss +/- fever common (mimics polymyalgia rheumatica but the myalgias are usually less severe) ● ocular muscles not involved, oropharyngeal muscles rarely involved ● may sometimes have muscle tenderness and swelling ● symmetrical peri-orbital heliotrope rash (violaceous to dusky rash +/- edema), erythematous rash over face and upper trunk, and Gottron's papules over the knuckles is characteristic of dermatomyositis ● dysphagia (without tongue dysarthria or extraocular involvement) and polyarthritis occur in both conditions ● may overlap with other connective diseases (eg. mixed connective tissue disease, rheumatoid arthritis, scleroderma, Sjogrens syndrome and systemic lupus erythematosis) and many other auto-immune diseases ● increased risk of an associated malignancy (especially in dermatomyositis patients > 50 years) ● myositis-specific antibodies may be present ● serum CK increased to 5 - 50x normal

Trichinosis myositis

● GIT symptoms begin 2 - 3 days after parasite ingestion (undercooked pork or game) ● fever, malaise, vomiting, diarrhea, peri-orbital edema of the face ● severe myalgia common ● stiff, swollen tender muscles ● extraocular muscles, masseters, larynyx, tongue, neck muscles, diaphragm, intercostals, limb flexors and lumbar muscles are most frequently involved; quadriplegia rare ● cardiomyopathy and CNS involvement rare http://www.homestead.com/emguidemaps/files/nmweakness.html (19 of 35)8/20/2004 5:14:35 PM nmweakness

● leucocytosis (65%), eosinophilia common after 10 days, positive serology delayed 2 - 3 weeks, elevated serum CK ++

X-linked dystrophy

● most common types include Duchenne's muscular dystrophy and Becker's muscular dystrophy => Duchenne's muscular dystrophy presents in early childhood with running difficulties and difficulty climbing stairs => lower extremity, lower trunk and pelvic girdle weakness ● progressive severe generalized weakness, sparing cranial muscles, with joint contractures of the lower limbs common ● may result in ventilatory failure with death before the end of the second decade ● associated hypertrophic cardiomyopathy

Myotonic dystrophy

● most common muscular dystrophy in adults ● generalized weakness, involving cranial nerves and distal muscles, with myotonia common ● weakness of facial muscles, with characteristic temporalis and masseter muscle atrophy; face is hatched and thin with ptosis and frontal balding; disproportionate sternocleidomastoid muscle weakness compared to other shoulder and neck muscles ● may produce ventilatory failure ● tendon reflexes may be reduced or absent ● associated findings include cardiomyopathy, which can cause sudden death

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Acid maltase deficiency (glycogenolysis type II)

● three forms - infantile, childhood and adult forms ● due to a deficiency in lysosomal alpha-glucosidase ● infantile form (Pompe disease) presents in the first few months of life with hypotonia, weak bulky muscles, macroglossia, hepatomegaly, cardiomegaly, congestive heart failure => progressive disease => death in 1 - 2 years from respiratory failure or other complications ● childhood form produces proximal muscle weakness, +/- muscle hypertrophy; respiratory muscle involvement common => may produce ventilatory failure ● adult form presents after age 20 years with progressive proximal muscle weakness (especially diaphragm, biceps, shoulder, and thigh adductors); respiratory failure is the presentation in 30% of patients and it eventually occurs in 100% of patients

Mitochondrial myopathy

● generalized weakness and ophthalmoparesis ● exercise intolerance; muscle cramps and myoglobinuria rare ● excessive lacticacidosis at rest with excessive rise after mild exercise ● may produce ventilatory failure

Neuromuscular junction disorders Myasthenia gravis

● pathologic hallmark is muscle fatigueability ● weakness may be precipitated by infection, drugs, heat, stress, menses or pregnancy ● chronic and fluctuating course ● predominance of ocular and bulbar involvement (ptosis, diplopia, dysphagia, dysarthria) ● upper limbs usually affected more than lower limbs ● respiratory muscle involvement may produce ventilatory failure ● episodic weakness is worse as the day proceeds and is aggravated by exercise, and relieved by rest ● myasthenic crisis may be precipitated by drugs (see list in the appendix)

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● normal pupillary responses, normal deep tendon reflexes and no sensory loss ● positive response to tensilon ● aggravation of weakness following tensilon administration suggests a cholinergic crisis

Lambert-Eaton myasthenic syndrome (LEMS)

● gradual onset of fluctuating proximal weakness mainly involving the legs producing a waddling gait ● muscle fatigibility common, mild exercise may increase muscle strength (this "warming-up" phenomenon is the opposite to the fatigueability phenomenon seen in myasthenia gravis) ● sustained exercise, heat or fever may aggravate weakness ● muscles may ache and are occasionally tender ● tendon reflexes may be reduced or absent, but reflexes improve with repeated testing ● ocular and oropharyngeal muscles rarely affected (opposite of myasthenia gravis) ● respiratory failure uncommon ● may be discovered because of prolonged recovery following use of neuromuscular blocking agents during anesthesia for surgery ● may be exacerbated by drugs - aminoglycoside or fluoroquinone antibiotics, magnesium, calcium channel blockers, iodinated IV contrast media ● no sensory loss ● associated with underlying malignancy (small cell carcinoma of lung most common), and muscle weakness may precede the malignancy ● dry mouth (hypo-salivation) and perversion of taste (metallic mouth taste) is a common associated complaint; other dysautonomias may occur (hypohidrosis and impotence) ● weakness may rarely respond positively to tensilon (false- positive test)

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Botulism

● rapidly progressive muscle weakness, often starting in the extraocular and pharyngeal muscles (diplopia, blurred vision, ptosis, dysarthria and dysphagia) => upper limb weakness => lower limb weakness => respiratory failure (descending paralysis) ● no sensory signs ● accomodative paresis and 6th nerve palsies are early signs ● fixed dilated pupils common (50%) ● other autonomic symptoms common (bradycardia, hypotension, hypohydrosis, constipation, ileus and dry mouth) ● history of consuming home-canned foods 12 - 24 hours prior to symptoms ● wound botulism (eg. drug abusers using black tar heroin => skin popping => sc abscesses or muscle abscesses) may produce delayed symptoms (1 - 2 weeks after wound contamination) ● no response to tensilon => empiric treatment may be necessary if the tensilon test is negative and ADIP and tick paralysis are excluded, and the etiology remains uncertain

Hypermagnesemia

● seen in eclamptic patients treated with parenteral magnesium, or in patients with renal failure and magnesium-antacid abuse ● serum magnesium usually > 10 mg/dl ● ocular, cranial and respiratory weakness can occur ● associated with metabolic encephalopathy

Peripheral nerve disorders

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Acute inflammatory demyelinating polyradiculopathy (Guillan- Barre syndrome)

● the most common cause of acute generalized neuromuscular weakness ● usually produces an ascending symmetric paralysis starting distally in the legs and then ascending over a few days + absent DTRs + sensory paresthesias +/- no sensory loss ● mild-to-moderate distal limb paresthesias may precede weakness by 1 - 2 days ● the presence of normal reflexes in the presence of severe generalized weakness virtually rules-out the diagnosis; a sharp sensory level or asymmetric weakness or marked bowel or bladder dysfuction at the onset rules-out the diagnosis ● usually progesses over days/weeks, but may be rapidly progressive over 24 - 48 hours ● many different variants, and may present with proximal > distal weakness, upper limb > lower limb weakness ● some patients may have sensory deficits - especially loss of vibration and proprioceptive sensation ● 50% of cases are associated with cranial nerve involvement, oropharyngeal weakness, and autonomic dysfunction (labile hypertension, tachycardia and decreased sweating) - the degree of dysautonomia may parallel the degree of weakness ● may produce respiratory weakness, which can correlate with the degree of impairment of shoulder elevation and neck flexion ● Miller-Fisher variant consists of total external ophthalmoplegia, loss of tendon reflexes and ataxia; patient often presents with diplopia, clumsiness and gait disorder; oropharyngeal weakness less common; no vertigo, nystagmus or cerebellar dysarthria; weakness may progress to a descending paralysis (mimicing botulism) ● often preceded by a viral syndrome or gastro-enteritis picture a few weeks before acute paralysis ● other associations include viral hepatitis, mycoplasma, Lyme disease, sarcoidosis, Hodgkins lymphoma, organ transplantations and recent vaccinations ● normal CSF in the first 24 - 48 hours; abnormal CSF findings seen after a few days => increased CSF protein and no cells (albuminocytologic dissociation); 5 - 10% of patients have a CSF lymphocytosis of < 100 cells/cu.mm http://www.homestead.com/emguidemaps/files/nmweakness.html (24 of 35)8/20/2004 5:14:35 PM nmweakness

● immunologic disorder associated with patchy demyelination of nerve roots and peripheral nerves ● axonal degeneration seen in cases associated with Campylobactor infection and anti-GM1 ganglioside IgG antibodies => severe paralysis is common

Tick paralysis

● north-western USA ● irritability and myalgia < 7 days after tick attachment ● rapidly ascending flaccid paralysis over 1 - 3 days ● cranial nerve involvement common, respiratory failure rare ● ataxia and sensory changes rare, DTRs decreased or absent ● rapid improvement following tick removal (often imbedded in the scalp)

Vasculitic neuropathy

● multiple overlapping neuropathies ● asymmetric onset, with rapid evolution to generalized weakness, sensory loss and pain ● usually occurs in the context of systemic vasculitis signs ● seen in systemic lupus erythematosis, scleroderma, polyarteritis nodosa, rheumatoid arthritis, cryoglobulinemia and many other vasculitidies ● see this website for further problem-solving information http:// www.neuro.wustl.edu/neuromuscular/antibody/pnimax. html#vasculitis

Acute intermittent porphyria

● attacks may be precipitated by drugs (barbiturates, phenytoin, sulfonamides, estrogens) ● attacks can also be precipitated by prolonged fasting, infection or menses ● symmetric polyneuropathy with prominent motor weakness and lesser sensory loss (arms > legs); severe paresthesias may occur ● associated with abdominal pain, altered mental status (confusion or delirium or pschosis) ● may be accompanied by autonomic instability (fever,

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Acute diptheritic neuropathy

● first presents with palatal weakness a few weeks after an infected sore throat ● a local cranial polyneuropathy with paralysis of pupillary accomodation, nasal speech due to palatal paralysis, dysphagia and respiratory compromise may occur 3 - 4 weeks after the initial throat infection; pupillary light reaction is normal ● a secondary generalized sensorimotor neuropathy may follow (8 - 12 weeks after infection) - which can be asymmetric, and occasionally proximal greater than distal; severe myalgia may occur ● respiratory paralysis occurs in severe cases

Arsenic neuropathy

● the most common form of acute heavy metal poisoning in the USA ● subacute sensorimotor polyneuropathy mimicing Guillain- Barre syndrome ● painful distal paresthesias common ● associated encephalopathy and systemic symptoms common ● subacute toxicity may produce skin pigmentation, eczematous rashes, Mees' lines and Raynaud's acrocyanosis ● causes include accidental exposure to weed killers or insecticides, history of drinking well water or contaminated wine or moonshine, occupational exposure (metal ore smelting) or intentional homicidal poisoning

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Shellfish toxins

● tetrodotoxin (pufferfish) ● ciguatoxin (ciguatera) ● saxitoxin (paralytic shellfish poisoning) ● brevitoxin (neurolytic shellfish poisoning) ● often associated with gastro-enteritis symptoms ● rapildy progressive peripheral neuropathy develops within minutes-hours of marine fish ingestion => ascending paralysis ● bizarre and/or painful sensory symptoms common

Hypophosphatemia

● seen in parenteral hyperalimentation, acute alcohol intoxication, starvation followed by a large glucose load, phosphate-binding antacids, and rarely in DKA ● serum phosphate usually < 1.0 mg/dl, often < 0.5mg/dl ● pronounced paresthesias of the hands, feet and peri-oral area are the earliest symptoms => generalized weakness follows ● hypoactive or absent tendon reflexes ● ocular, cranial and respiratory weakness can occur ● associated encephalopathy common

Motor neuron disorders Amyotrophic lateral sclerosis

● usually produces generalized weakness with marked atrophy and fasiculations ● weakness may be patchy and asymmetric ● oropharyngeal weakness common (bulbar onset in 20 - 30% of cases) ● typical pattern is combined UMN and LMN signs ● tendon reflexes may be pathologically brisk, especially in the lower limbs ● respiratory failure may occur in isolation; early suggestive symptoms may include sleep disorders, dyspnea or morning headache; associated with weight loss, loss of sense of taste and depression ● see this website for further problem-solving information http:// www.neuro.wustl.edu/neuromuscular/spinal/als.htm

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Poliomyelitis

● presents with acute febrile viral meningitis syndrome followed by asymmetric limb weakness within 2 - 5 days ● patient may suffer from intense myalgias and hyperalgesia ● weakness may be fulminant, acute or subacute; pattern may be legs > arms > bulbar ● autonomic dysfunction may be prominent (blood pressure lability, arrhythmias, constipation and ileus, hyperhydrosis or hypohydrosis, urinary retention) ● electrophysiologic studies can differentiate polio from a peripheral neuropathy ● can follow oral polio vaccine administration in patients with an immunologic disorder eg. hypogammaglobulinemia

Spinal cord disorders Transverse myelitis

● sudden onset of paraplegia + sensory level (all sensory modalities lost below that level) + band of paresthesia at level of lesion + inability to void (developing over hours-days) ● prodrome:- febrile illness 37% vaccination 15% ● isolated cases may follow a recent viral infection (EBV, CMV, rubella, hepatitis, measles, HIV, HTLV-1); may also be due to multiple sclerosis, mycoplasma, herpes zoster, tuberculosis, syphilis, sarcoidosis, systemic lupus erythematosis and antiphospoholipid antibody syndrome ● differentiated from AIDP and other neuromuscular causes of sudden weakness by a "sensory level" +/- bladder involvement (40%) and erectile dysfunction (90%)

Spinal cord infarction

● usually due to anterior spinal artery obstruction eg. aortic dissection, trauma, vasculitis, hypotensive episode in narrowed artery, scuba diving and secondary air embolism ● involves the thoracic or caudal spinal cord => sudden flaccid, areflexic paraparesis + dissociated sensory loss (loss of pain and temperature sensation + retention of vibration and proprioceptive sensation) + inability to void

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Spinal cord compression syndrome

● sudden back pain + paraplegia + sensory level ● acute etiologies include tumor (primary or metastatic), epidural abscess, epidural hematoma, vascular malformation and herniated disc ● see the low back pain guidemap for further details

Diagnostic workup of acute neuromuscular weakness

- the diagnostic workup may be limited if the clinical diagnosis is certain eg. ADIP, periodic paralysis, or UMN tetraparesis

- it is always worthwhile to obtain baseline bloodwork - CBC, serum electrolytes, serum calcium, magnesium and phosphate (+/- serum CK if a myopathy is a diagnostic consideration)

- a more extensive diagnostic workup may be required if the diagnosis is uncertain, and the following diagnostic tests should be considered, and selectively performed

● emergent MRI of the spine if the examination suggests a focal spinal lesion eg. discrete sensory level +/- muscle weakness below that level; selective areflexia with absent lower limb reflexes and normal upper limb reflexes; UMN-type paraparesis without arm weakness ● emergent CT scan of the head for acute hemiplegia, tetraparesis +/- altered LOC +/- brainstem signs, or monoplegia ● emergent X-ray of C-spine in a rheumatoid arthritis patient with tetraparesis due to a spinal cord lesion to exclude alanto-axial dislocation ● CSF examination looking for evidence of AIDP (albuminocytologic dissociation), transverse myelitis or poliomyelitis (aseptic meningitis) ● serum electrolytes (especially serum potassium and sodium), serum phosphate, calcium and magnesium ● BUN and creatinine to r/o underlying renal failure, or rhabdomyolysis-induced renal failure ● serum T4 and TSH if hypokalemic periodic paralysis suspected ● serum CK - marked elevation strongly suggests a myositis ● urine myoglobulin - elevation suggests rhabdomyolysis and a possible metabolic myopathy ● eosinophilia may suggest trichinosis ● elevated sed rate suggests polymyositis, dermatomyostis or systemic lupus

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- if the clinical picture suggests a myopathy, and the diagnosis is not clear; or if the myopathic clinical presentation is associated with myoglobinuria => the following sub- guidemap on myopathy and myoglobinuria may provide more information that may be useful in determining the likely cause of the myopathy

- patients with rapidly progressive muscle weakness are at risk of respiratory failure, and admission to an ICU for observation and regular VC monitoring may be warranted

Consult this excellent website for detailed information on neuromuscular disorders

http://www.neuro.wustl.edu/neuromuscular

Appendix

Medical Research Council rating of muscle strength

Grade 1 = no contraction Grade 2- = flicker or trace of contraction Grade 2+ = active movement, with gravity eliminated Grade 3 = active movement against gravity Grade 4- = active movement against light resistance Grade 4 = active movement aginst moderate resistance Grade 4+ = active movement against heavy resistance Grade 5 = normal muscle power

Practical muscle strength testing

- a quick sensitive test for upper limb muscle weakness is to check for pronator drift => the patient is instructed to lift both upper limbs to shoulder level with both forearms held in front in supination with palms-up => a slow pronation and downward drift of the arms suggests muscle weakness http://www.homestead.com/emguidemaps/files/nmweakness.html (30 of 35)8/20/2004 5:14:35 PM nmweakness

- a quick sensitive test for lower limb muscle weakness is to get the supine patient to elevate the thigh against gravity and active resistance, and to ambulate on the toes and heels

- neck extensor and neck flexor strength is tested against gravity and active resistance

- muscle strength above the neck is tested by asking the patient to pout, elevate the eyebrows, close the eyelids forcefully, blow the cheeks-out (7th cranial nerve); keep the jaw closed against active attempts to open the mouth, move the jaw from side-to-side (5th cranial nerve); push the tongue against a tongue blade held to the left and right of the mouth (12th cranial nerve)

- more thorough limb muscle strength testing can be achieved by testing a multiplicity of limb joint movement strengths, and it is most useful when localising the level of a spinal cord lesion or differentiating proximal from distal muscle weakness eg. upper limb - arm abduction at the shoulder (C5), elbow flexion (C5,6) and extension (C6,7), wrist flexion (C6,7,8) and extension (C6,7), finger flexion (C8, T1) and extension (C7); lower limb - hip flexion (L1, 2,3) and extension (L5, S1), knee flexion (L4,5,S1,2) and extension (L3,4), foot plantar flexion (S1) and dorsiflexion (L5)

Motor testing

- there is no "pure" single nerve testing of the upper and lower limbs

- some easy-to-remember combinations include:-

● shoulder abduction - C5 ● elbow flexion - C 5,6 ● elbow extension - C7 ● wrist and finger extension - C7 ● finger flexion - C8 ● finger abduction - C8, T1 ● thumb adduction and opponens - T1 ● hip flexion - L 2, 3, 4 ● knee extension - L 3, 4 ● foot dorsiflexion - L 4, 5 ● 2nd - 5th toe dorsiflexion - L 5 ● 1st toe dorsiflexion - L 5 or S1 ● foot plantar flexion - S1 ● squeezing buttocks together (gluteus maximus) - S1 ● anal sphincter "tightening" - S2, 3, 4

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- the biceps reflex is C5/6, triceps reflex is C7/8, knee reflex is L3/4 and the ankle reflex is S1

(* although many textbooks/journal articles suggest that first toe dorsiflexion innervation is primarily from L5, other textbooks/journal articles suggest S1 as the major innervation=> because of this discrepancy in opinions, it is recommended that you use foot and small toe(s) dorsiflexion for L5 testing and plantar flexion of the foot for S1 testing)

- detailed muscle strength testing is useful in patients with asymmetric or focal weakness, and it may enable a physician to differentiate between a plexopathy, radiculopathy or peripheral nerve pathology

Detailed muscle strength testing - upper limb Muscle Segmental Peripheral nerve Muscle action nerve supply Deltoid C5 Circumflex Arm abduction Infraspinatus C5 Suprascapular External rotation of the arm Serratus anterior C5,6,7 Long thoracic nerve Patient pushes arm - held forward 90 degrees- against firm obstruction => muscle prevents scapular winging Latissimus dorsi C7 Nerve to latissimus dorsi Adducts arm - held in abduction - towards chest Biceps C5 Musculocutaneous Elbow flexion Triceps C7 Radial Elbow extension Extensor carpi C6,7 Radial Extension of the radialis longus wrist radially Extensor carpi C7 Radial Extension of the radialis ulnaris wrist ulnarly

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Extensor C7 Radial Finger extension digitorum at MP joints Flexor carpi C6,7 Median Wrist flexion radialis radially Flexor carpi C8 Ulnar Wrist flexion ulnaris ulnarly Abductor C8 Radial Thumb pollicis longus abduction at MP joint Extensor pollicis C8 Radial Thumb brevis extension at MP joint Extensor pollicis C8 Radial Thumb longus extension at thumb IP joint Opponens T1 Median Opposition of pollicis thumb to small finger Abductor T1 Median Abduction of pollicis brevis thumb at MP joint Flexor pollicis C8 Median Flexion of the longus thumb IP joint Adductor pollicis T1 Ulnar Thumb adduction Lumbricals and C8,T1 Lumbricals I, II - Flexion of the interossei Median extended fingers Interossei and at the MP joint lumbricals III and IV - (lumbricals) Ulnar Finger abduction (interossei) Flexor digitorum C8 Median Finger flexion at sublimus PIP joint Flexor digitorum C8 Median - I, II Finger flexion at profundus Ulnar - II, IV DIP joint Abductor digiti T1 Ulnar Abduction of minimi little finger

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Detailed muscle strength testing - lower limb Muscle Segmental Peripheral nerve Muscle action nerve supply Iliopsoas L1,2,3 Femoral Thigh flexion Adductor femoris L5, S1 Obturator Thigh adduction Gluteus medius L4, 5, S1 Superior gluteal Thigh abduction Gluteus maximus L5, S1 Inferior gluteal Thigh extension Hamstrings of thigh L5, 5, S1, 2 Sciatic Knee flexion Quadriceps femoris L3, 4 Femoral Knee extension Tibialis anterior L4, 5 Deep peroneal Foot dorsiflexion Tibialis posterior L4 Tibial Foot plantar flexion and inversion Peronei L5, S1 Superficial Foot eversion peroneal Gastrocnemius S1 Tibial Foot plantar flexion Extensor digitorum L5 Deep peroneal Toe dorsiflexion longus Flexor digitorum S1, 2 Tibial Toe plantar longus flexion Extensor hallucis L5, S1 Deep peroneal Hallux longus dorsiflexion

Muscle stretch reflexes Reflex Segmental innervation Nerve Jaw jerk Pons Trigeminal - mandibular branch Biceps jerk C5, C6 Musculocutaneous Brachioradialis jerk C5, C6 Radial Triceps jerk C7, C8 Radial Finger jerk C8, T1 Median

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Knee jerk L3, L4 Femoral Ankle jerk S1, S2 Tibial

Drugs precipitating or aggravating neuromuscular weakness Drugs that cause motor Drugs that can impair neuropathy neuromuscular transmission

● dapsone ● ACTH ● imipramine ● aminoglycoside antibiotics ● certain sulfonamides ● beta blockers ● choloroquine Drugs associated with myopathy ● colistin ● corticosteroids ● lithium ● beta-blockers ● magnesium-containing cathartics ● chloroquine ● penicillamine ● clofibrate ● phenothiazines ● corticosteroids ● polymixin ● drugs causing hypokalemia ● procainamide ● emetine ● quinine ● epsilon-aminocaproic acid ● quinidine ● penicillamine ● tetracycline ● zidovudine ● vancomycin

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemap - Gait disorders, drop attacks and frequent falls

Click on any of the headings or subheadings to rapidly navigate to the relevant section of the guidemap

Introduction

Clinical evaluation of a gait disorder

● standing posture

● walking ability

● basal ganglia gait disorders

● higher level gait disorders

● psychogenic gait disorder

● summary of the major clinical differences between ataxic conditions causing a wide based gait

● differentiating between Parkinson's disease and symptomatic Parkinsonism in akinetic-rigid syndromes

● drop attacks and frequent falls

Appendix

● classification of gait disorders

● Romberg's test

Introduction

- this guidemap is a companion guidemap to the ataxia, incoordination and dysequilirium guidemap, and it may prove useful if an ataxic patient does not have definite clinical signs of cerebellar disease, acute vestibular syndrome or sensory ataxia; and an emergency physician is seeking guidance on how to r/o other causes of ataxia or disordered gait

- this guidemap is not comprehensive and it does not deal with gait disorders in depth; it is only focused on supplying enough information to allow an emergency physician to recognize some gait disorders due to underlying neurological disease

- there are many reasons why an elderly patient may fall, which are unrelated to a

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● normal age-related posture and gait changes ● visual impairment (eg. cataracts) ● near-syncopal or syncopal events ● postural orthostatic hypotension ● polypharmacy and impaired reflexes or secondary autonomic dysfunction ● enviromental factors

- it is usually possible to establish a topographic diagnosis (site of the lesion) in a patient with a neurological gait disorder, on the basis of a formal neurological examination and observation of the patient's gait

- the recommended gait evaluation should include the following elements, in addition to a formal neurologic and musculoskeletal examination

● posture of the head, neck and trunk ● stance and Romberg's test ● postural reflexes ● step initiation ● walking pattern ● associated trunk and arm movements

Clinical evaluation of a gait disorder

- the clinical evaluation should be focused on identifying some common gait disorder patterns - cerebellar ataxia, vestibular ataxia, sensory ataxia, parkinsonian (akinetic rigid) ataxia, frontal lobe ataxia,and spastic paraplegic ataxia

- after first completing a thorough neurological examination, the clinical approach to an ataxic patient involves an assessment of the patient's standing posture (trunk, stance, postural reflexes) and walking ability (initiation, stepping, associated truncal and upper limb movement)

Standing posture

Trunk posture

- normal subjects stand and walk with an upright posture

- in Parkinson's disease the trunk becomes stooped and flexed and the neck is flexed; neck

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- a variety of distorted body postures suggest torsion dystonia

- proximal hip muscles weakness, due to a myopathy, causes an exaggerated lordosis

Stance

- assess the patient's stance width, body sway, and ability to balance on two legs during quiet standing

- wide-based gaits suggest a cerebellar or sensory ataxia, diffuse cerebral disease, and frontal lobe lesions; those patients have difficulty standing on one foot or standing with both feet close together

(* a patient who can stand on one foot, with the eyes closed, is unlikely to have objective evidence of a postural balance problem)

- a shaky tremulous stance is seen in Parkinson's disease

- subtle degrees of imbalance can be unmasked by instructing the patient to deliberatedly adopt a narrow stance width when standing, and by watching the patient tandem walk heel- to-toe in a straight line, which tests lateral stability (significantly impaired in cerebellar ataxia)

- because vision is crucial for maintenance of balance in patients with sensory ataxia, instruct the patient to close his eyes during quiet standing (Romberg's test) => the patient with sensory ataxia will sway to the point of falling as unsteadiness dramatically increases

(* see the appendix for further information on Romberg's test)

Postural reflexes

- these reflexes can be tested by gently pushing the standing patient backwards or forwards

- mildly impaired postural reflexes is suggested if the patient takes a few short shuffling steps backwards (retropulsion) or forwards (propulsion), while severely impaired postural reflexes will cause the patient to fall

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Initiation

- start hesitation with shuffling on the spot ("slipping clutch" phenomenon) or an inability to lift the feet from the floor ("magnetic feet" or "stuck-to-the-floor" phenomenon) are signs of difficulty initiating gait, and start hesitation (freezing of gait) is usually seen in extrapyramidal syndromes, frontal lobe lesions, and rarely as an isolated condition (gait ignition failure)

- freezing of gait is a midline phenomenon and usually involves both legs, but in asymmetric Parkinsonism unilateral or asymmetric freezing can occur

- freezing of gait (FOG) is often worse in stressful situations eg. answering a doorbell, crossing a street at a green light

- one of the classical features of FOG is its dramatic and continuous response to motor or behavioural tricks eg. moderate emotional distress may improve FOG (level of function better in the doctor' office compared to level of function at home, where FOG is at its worst)

Stepping

- when walking is underway, assess the patient's stride length, rhythm and speed of walking over a distance of 5 - 10 metres, and note his ability to quickly turn around and negotiate obstructions

- in parkinsonian syndromes, the length of each step is short, and steps may be slow and shallow, although the normal rhythm of walking is maintained

- in cerebellar ataxia, the steps are of variable length and irregular in rhythm, giving the gait a jerky and lurching quality, which is exacerbated when the patient needs to turn corners => the patient's walk may take a zig-zag course mimicing a drunken sailor; there may also be titubation and swaying of the head and trunk; widening of the base only during turns or merely taking an extra one-or-two steps during sudden turns to maintain balance + slight difficulty with tandem walking may be the earliest signs of cerebellar ataxia

- the pattern of cerebellar ataxia depends on the site of the pathology => lesions of the flocculonodular lobe (vestibulocerebellum) may produce marked dysequilibrium causing postural ataxia during sitting or standing + severe gait ataxia and falling in any direction +/- truncal titubation when sitting or standing + few/no other cerebellar signs; http://www.homestead.com/emguidemaps/files/gait.html (4 of 17)8/20/2004 5:14:38 PM gait lesions of the anterior vermis (spinocerebellum) may produce a wide-based gait with a slow and irregular cadence and superimposed lurching, but no/few other signs of incoordination; lesions of the lateral cerebellar hemispheres (frontocerebellum) mainly produce limb ataxia and secondary gait incoordination with a tendency to veer towards the ipsilateral side + multiple associated cerebellar hemisphere signs, but no true truncal ataxia

- in sensory ataxia, the steps are slow and deliberate and placed carefully under direct visual guidance, sometimes striking the ground with the heel then the foot, making a slapping sound (slapping gait); gait is much more impaired when walking in the dark and the feet may be raised too high, thrown too far forward and brought down too hard; the patient shows poor/absent postural responses to surface perturbations even with the eyes open

- in vestibular ataxia due to bilateral peripheral vestibular dysfunction, the patient may have normal gait under usual circumstances, but have significantly impaired gait when vision and proprioceptive cues are reduced or deceptive eg. walking in the dark or over uneven ground; the patient may try and keep the head still while walking to prevent oscillopsia and secondary dysequilibrium (stiff "en bloc" gait)

- in vestibular ataxia due to unilateral peripheral vestibular dysfunction, the patient often has marked vertigo and secondary autonomic symptoms during the acute phase and is disinclined to walk; if coaxed to walk the patient tends to fall or stagger towards the affected side (opposite in direction to the subjective sense of self-motion and the rapid phase of nystagmus); balance is much better when running versus slow walking

- in upper motor neuron disease, the patient stands with slight flexion at the hips and knees, but on starting to walk, the leg stiffens and extends slightly at the knee; most of the lower limb movement comes from the hip and walking involves circumduction of the stiffened leg during the swing phase of each step, with scraping of the toes of the shoe on the ground beneath as the trunk undergoes slight flexion to the opposite side to allow the hyperextended leg to swing through; severe thigh adductor spasm may even cause the the circumducted leg to cross the midline during the swing phase producing a scissoring gait

(* the characteristic clinical picture of a spastic hemiparesis includes the arm posture of abduction and internal rotation of the shoulder, pronation of the forearm and flexion of the wrist and fingers, with a minimum of associated arm swing on the affected side; in spastic paraparesis there is slight flexion at the hips, both legs are extended at the knees, and the feet adopt a posture of plantar flexion => gait is slow as the patient proceeds by dragging the circumducted legs forward, one step after another; the most common cause of a spastic paraplegia in an elderly patient is a spinal myelopathy due to cervical spondylosis; patients with hereditary spastic paraplegia or cerebral palsy have only

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(* see the spinal cord syndromes guidemap for futher problem-solving information on UMN motor and sensory signs)

- in lower motor neuron disease involving the proximal hip and pelvic muscles, weakness of the hip extensors leads to an exaggerated lordosis; flexion of the hips and a failure to stabilize the pelvis during walking => leads to an exaggerated pelvic tilt and a waddling gait

- in distal lower motor neuron weakness causing foot drop, the legs are lifted abnormally high with each step, descending to strike the floor with the toes first and then the heel (steppage gait)

- dystonic syndromes may produce bizarre gait abnormalities, which can lead to a misdiagnosis of psychogenic gait disorder

- patients with chorea often incorporate the involuntary movements into their gait, describing an irregular path with a dance-like pattern likened to a "puppet-on-a-string"

Associated movements

- normal subjects walk with flowing synergistic movements of the head, trunk and arms

- loss of synergistic arm movements is seen in akinetic-rigid syndromes, hemiparesis, spastic paresis and cerebellar ataxia

- an unilateral loss of arm swing may be an early sign of a hemiparesis or Parkinson's disease

Basal ganglia gait disorders

- the major deficit in early Parkinson's disease is a reduction in the speed and amplitude of leg movements, giving rise to a shuffling gait with small steps and no/little raising of the feet during walking (the foot is placed flat or plantarflexed during walking)

- the locomotor hypokinesia is associated with diminished arm swinging, and the body turns "en bloc" (head remains in line with the body during turning)

- as the disease progresses, freezing develops and the patient develops start hesitation

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- after walking starts, freezing may recur when the patient turns or enters a doorway or encounters an obstacle

- balance and postural reflexes are preserved in the early stages, although the response to a disturbance of posture is a series of short shuffling steps (propulsion, retropulsion, festination)

- postural instability and falling appear later in the disease course

- patients with other akinetic-rigid (Parkinson's plus) syndromes are more likely to have a wide-based gait, absent/poor postural reflexes and frequent falls

(* see the table differentiating Parkinson's disease from other akinetic-rigid syndromes)

It should be possible - based on the formal neurological examination + observation of standing posture and gait - to decide whether the patient has a lower-level or middle- level gait disorder

(* see the classification of gait disorders for a list of causes of gait disorders)

If the neurological examination and observation of the ataxic gait does not suggest a lower-middle-level gait disorder, consult the following brief synopses of different higher-level gait disorders for further problem-solving information

Higher-level gait disorders

Cautious gait (senile gait)

- many elderly people adopt this gait to compensate for arthritis or in response to frequent previous falls

- the patient appears to be adopting too many unnecessary precautions as if "walking on ice" - the feet are placed wide apart; the body and hips and knees are flexed to place the body directly over the widened base; the arms are held abducted and flexed in anticipation of an unexpected fall; walking proceeds with small tentative steps on a wide base and the patient frequently reaches out for furniture or other objects for support

- some elderly patients develop space phobia and only walk timidly around the periphery

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Subcortical dysequilibrium (astasia-abasia, thalamic astasia)

- astasia is motor incoordination and an inability to stand, abasia is an inability to walk

- secondary to thalamic or midbrain stroke; also seen early in the course of progressive Parkinson's-plus syndromes

- the patient has normal muscle strength on isometric testing and variable sensory loss

- the patient may be unable to stand because of an absence of postural reflexes, or the patient may fall over easily

- postural reflexes may also be inappropriate and the patient may extend the neck and fall backwards or sideways immediately on standing; extreme cases cannot even sit up unassisted

- if the patient can ambulate, the patient may have particular difficulty walking backwards and the patient needs to pay particular attention in order to walk satisfactorily

- associated neurological defects include vertical gaze palsies, dysarthria and extrapyramidal signs (proximal hypokinesia, and poverty in the performance of associated automatic movements)

Frontal dysequilibrium (frontal ataxia, gait apraxia)

- associated with frontal lobe disorders (tumor, abscess, infarction or normal pressure hydrocephalus)

- patients have difficulty in rising to stand upright because they do not bring their feet under themselves as they try to rise, and they may not even place their feet on the ground

- if helped to stand erect, they often arch back into hyperextension in seeming disregard for their support base

- there is often a complete breakdown in the organization of leg movements and the legs may scissors-cross in bizarre gait patterns, and there is no coordination between the trunk and legs

- can be distinguished from subcortical dysequilibrium because those patients can walk

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- associated with frontal dementia, urinary incontinence, frontal release signs and perseveration

Isolated gait ignition failure (gait apraxia, magnetic gait)

- characterized by an inability to initiate locomotion

- the patient may appear to be frozen to the spot on gait initiation, or when required to turn

- balance is preserved, postural responses are normal, gait width is normal and falls are very rare

- steps are initially short and shuffling, but become more normal as walking proceeds, and the arm swing also becomes normal when the patient eventually ambulates

- there are no physical signs of Parkinsonism or dementia

- the cause is unknown, and neuroimaging is required to r/o hydrocephalus or multi-infarct disease (both conditions are usually associated with dementia and urinary incontinence)

Frontal gait disorder (arteriosclerotic Parkinsonism, lower half Parkinsonism)

- seen in the multi-infarct state due to subcortical hypertensive arteriosclerotic encephalopathy (Binswanger's disease) and hydrocephalus

- the patient has a normal-wide base, stiff upright stance when standing and walking, difficulty initiating ambulation, short-stepped military gait with exaggerated arm movements, hesitation on turning, and freezing episodes

- there is some impairment of postural reflexes and a variable tendency to fall

- associated with cognitive impairment, pseudobulbar palsy, dysarthria, urinary incontinence, frontal release signs and pyramidal signs (UMN signs)

- no signs of Parkinson's disease (rest tremor, facial immobility, reduced upper arm movements, bradykinesia)

Psychogenic gait disorder

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- psychiatric findings are heterogenous and some patients have depression while other patients have conversion hysteria disorder

- clinical features suggestive of psychogenic gait ataxia

● momentary fluctuations of stance and gait, often in response to suggestion or distraction ● excessive slowness or hesitation, incompatible with neurological disease ● psychogenic Romberg's test with build-up of sway amplitudes or improvement with suggestion ● uneconomic postures with wastage of muscle energy ● "walking on ice" gait pattern ● sudden buckling of the knees without falling ● bizarre, wild lurching and weaving movements during ambulation - without ever falling

Summary of the clinical differences between major ataxic conditions causing a wide based gait Cerebellar ataxia Sensory ataxia Frontal lobe

ataxia Trunk posture Stooped-leans Stooped-upright Upright forward Stance Wide-based Wide-based Wide-based Initiation of gait Normal Normal-wariness Start hesitation Postural reflexes +/- Intact May be absent Steps Stagger-lurching High-stepping Small-shuffling Stride length Irregular Regular Short Leg movement Variable, ataxic Variable - hesitant Stiff, rigid and slow Speed of Normal-slow Normal-slow Very slow movement Arm swing Normal, Normal Exaggerated exaggerated Turning corners Veers away Minimal effect Freezing-shuffling Heel-toe test Unable +/- Unable Romberg's test +/- Increased +/- unsteadiness

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Heel-shin test Usually abnormal +/- Normal Falls Uncommon Yes Very common

Differentiating between Parkinson's disease and symptomatic Parkinsonism in akinetic-rigid syndromes Parkinson's disease Symptomatic parkinsonism Posture Stooped (trunk flexion) Stooped/upright (trunk flexion or extension) Stance Narrow Often wide-based Postural reflexes Preserved in early stages Absent at early stage Initiation of walking Start hesitation Start hesitation Steps Small and shuffling Small and shuffling Freezing Common Common Festination Common Rare Arm swing Reduced-absent Reduced Heel-toe walking Normal Poor Falls Late (forwards-tripping) Early and severe (backwards)

Drop attacks and frequent falls

A drop attack is defined as a sudden fall, with or without loss of consciousness, due either to collapse of muscle tone (a negative phenomenon) or abnormal muscle contraction in the legs (a positive phenomenon)

(* some physicians exclude any patients with loss of consciousness from the category of drop attacks)

- about two-thirds of drop attacks of are of unknown etiology

- many neurological and cardiac diseases can cause drop attacks, and a brief discussion of some causes of drop attacks follows:-

Proximal weakness of the legs

- some causes include muscular dystrophy, neurogenic atrophy, polymyositis, inclusion body myositis, myasthenia gravis and spinal cord ischemic attacks http://www.homestead.com/emguidemaps/files/gait.html (11 of 17)8/20/2004 5:14:38 PM gait

- Duchenne's muscular dystrophy is the most common muscle dystrophy to cause weakness of the hip and knee extensors, which are important for maintaining an erect posture

- rarely, middle-aged patients may develop drop attacks due to isolated quadriceps weakness, secondary to diseases like polymyositis, inclusion body myositis and neurogenic atrophy, and the legs may suddenly give way without warning to cause falls

- intermittent spinal ischemia can produce sudden attacks of transient paraparesis or falls, and causes include syphilitic arteritis, arteriosclerosis of the distal aorta, adhesive arcachnoiditis, spinal compression due to spinal stenosis or disc herniation; the attacks are often precipitated by exercise and relieved by rest

Neurodegenerative diseases

- patients with Parkinson's disease often fall due to defective postural reflexes, sudden freezing, and uncoordinated turning; their stooped flexed posture predisposes them to falling forward because their centre of gravity is displaced forward when standing or walking; drug-induced dyskinesias and orthostatic hypotension can also predispose them to falls

- patients with Parkinon's plus syndromes (other akinetic-rigid disorders) are more prone to fall

- falling is the most frequent initial presenting symptom in progressive supranuclear palsy, and PSP patients tend to extend their necks and fall backwards; stiff legs + wide- based gait + absent postural reflexes + characteristic down-gaze palsy predisposes PSP patients to frequent falls

- other neurodegenerative diseases associated with frequent falls include corticobasal degeneration, Huntingdon's chorea, multiple system atrophy and Alzheimer's disease

Transient ischemic attacks

- the patient with vertebro-basilar artery ischemia can present with a sudden loss of tone in their legs, causing their knees to buckle => the patient falls powerlessly without protective arm movements; there may be no precipitating head or neck movements or loss of consciousness, and the patient can ususally get up and walk immediately or within one minute; usually other symptoms of brainstem ischemia are present (vertigo, diplopia, bluured vision, sensory changes, motor weakness and variable LOC), which suggest the diagnosis http://www.homestead.com/emguidemaps/files/gait.html (12 of 17)8/20/2004 5:14:38 PM gait

Epilepsy

- drop attacks can be due to sudden muscle contractions associated with generalized convulsive epilepsy, or a sudden loss of postural tone due to atonic epilepsy or epileptic negative myoclonus

- the Lennox-Gastaut syndrome consists of a variable mixture of myoclonic, atonic, tonic and abscence seizures; these patients have a past history of brain damage and mental retardation, and seizures occur between 6 months and 7 years

- atonic epileptic attacks in children can occur when standing or sitting or lying, and there is no aura or postictal state of confusion; sudden drop attacks can cause the patient to collapse like an accordion with triple flexion of the legs and no involvement of the arms => the patient can usually get up immediately after an attack

Various myoclonic syndromes

- mycoclonus is defined as a sudden brief, shock-like muscle movement caused by a brief muscle contraction (positive myoclonus) or inhibition of a muscle contraction (negative myoclonus)

- they can mimic idiopathic drop attacks, and the patient can fall suddenly with buckling of the legs

- many patients exhibit repetitive bouncing of the legs when they attempt to stand, due to repetitive negative myoclonus in the extensor support muscles of the trunk and hips

Startle reactions

- pathological startle reactions (hyperekplexia) are characterized by an exaggerated motor response to unexpected auditory stimuli, and less frequently to visual or somasthetic stimuli

- pathologic startle reactions consist of both brief myoclonic jerks and longer tonic spasms

- hyperekplexia may have a variety of causes eg. idiopathic, hereditary, or secondary to acquired brainstem diseases - post-anoxic encephalopathy, viral or paraneoplastic brainstem encephalitis, multiple sclerosis, sarcoidosis or brainstem strokes

- myoclonic jerks occur frequently during the day, but also at night when the patient is

http://www.homestead.com/emguidemaps/files/gait.html (13 of 17)8/20/2004 5:14:38 PM gait asleep, and mainly affect the legs

- sterotyped tonic spasms consist of facial grimacing, flexion of the neck and trunk, flexion or extension of the hips and knees, and characteristic abduction of the shoulders with flexion of the elbows => the patient falls forwards rigidly like a log, but sometimes falls backwards; protective reflexes are impossible and injuries common; consciousness in maintained during the fall and recovery is fast

Cataplexy and paroxysmal kinesigenic choreoathetosis

- cataplexy can cause sudden falls without LOC, but the patient cannot speak during the fall

- characteristic precipitating factors include laughter or a sudden emotional stimulus

- minor symptoms of cataplexy may consist of a brief drop of the jaw and sagging of the head, but severe attacks can cause loss of tone in all the antigravity muscles => the patient falls powerlessly and loosely and remains immobile for many seconds (longer than in hyperekplexia)

- attacks of paroxysmal kinesigenic choreoathetosis are usually precipitated by sudden leg movements during standing or running or social embarrassment => the patient may suddenly lose control due to tonic spasms or an involuntary choreoathetotic muscle movement and fall like a log

Focal structural lesions

- mass lesions around the foramen magnum can cause drop attacks (eg. odontoid process fractures, Arnold-Chiari type I malformations), and drop attacks can be precipitated by neck movements, coughing or sneezing, or vertical head compression; the drop attack patient presents with a stiff neck, spastic paraplegia. Lhermitte's sign and limb paresthesias

- other posterior fossa pathology can also cause drop attacks eg. posterior fossa arachnoid cysts, midline metastatic cerebellar tumors, vermis hemangioblastomas, and obstructive hydrocephalus due to third ventricle cysts

Meniere's drop attacks (Tumarkin's otolithic crisis)

- seen in the early or late stages of Meniere's disease when there is a sudden change in endolymphatic pressure which causes end-organ stimulation with a reflex-like vestibulospinal loss of postural tone http://www.homestead.com/emguidemaps/files/gait.html (14 of 17)8/20/2004 5:14:38 PM gait

- the patient suddenly loses control of balance and falls; the patient does not lose consciousness and he sometimes has the distinct feeling of being pushed or thrown to the ground

(* a patient with Wallenberg's syndrome, due to a lateral medullary stroke, may have a similar transient sensation of being pulled or pushed to the side, and the patient suddenly falls to the side without realizing that it is his active shift of the centre of gravity - lateropulsion - that causes the momentary imbalance)

Idiopathic drop attacks

- proposed diagnostic criteria include:- "A fall without warning, not associated with loss of consciousness, not apparently due to any malfunction of the legs, not induced by changes of posture or movement of the head, and not accompanied by vertigo or other cephalic sensation, and not associated with myoclonic jerks"

- usually appear between the ages 40 - 60 years

- patients only fall when standing or walking, and they usually buckle at the knees and fall forwards

- the attacks occur very suddenly and the patient cannot remember if he lost consciousness, or not; the patient can get up immediately unless accidental injury occurs (minor upper limb fractures and/or dislocations are common in the elderly)

- serial attacks are rare, and spontaneous remission is common (25 - 80%)

Appendix

Classification of gait disorders

Lowest-level gait disorders

Peripheral musculoskeletal problems

● arthritic gait ● myopathic gait ● peripheral neuropathic gait

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Peripheral sensory problems

● sensory ataxic gait ● vestibular ataxic gait ● visual ataxic gait

Middle-level gait disorders

● hemiplegic gait ● paraplegic gait ● cerebellar ataxic gait ● Parkinsonian gait ● choreic gait ● dystonic gait

Higher-level gait disorders

● cautious gait ● subcortical dysequilibrium ● frontal dysequilibrium ● isolated gait ignition failure ● frontal gait disorder ● psychogenic gait disorder

Romberg's test

- the test is primarily used to differentiate sensory ataxia from cerebellar ataxia

- Romberg's sign detects proprioceptive sensory loss by demonstrating loss of postural control in darkness

- the test is usually performed by having an examiner observing the patient's postural stability when the patient stands with the feet close together, initially with eyes open and then with eyes closed

- Romberg's sign is present when a patient is able to stand with feet together and eyes open, but sways or falls with the eyes closed

(* normal people may sway a little when the eyes are closed, and a Romberg test is only truly positive when the patient sways a great deal or falls)

http://www.homestead.com/emguidemaps/files/gait.html (16 of 17)8/20/2004 5:14:38 PM gait - the test is classically positive in patients with proprioceptive loss (due to dorsal column disease or peripheral sensory neuropathy) because they are dependent on visual cues to remain in a state of postural equilibrium; however, patients with bilateral vestibular damage are also dependent on visual cues for balance and they may also have a positive Romberg's sign

- some patients* with cerebellar ataxia also have a positive Romberg's sign and they are also dependent on visual cues for maintenance of postural balance while standing

(* the pathology lies in the anterior vermis and paravermis of the anterior lobe - spincocerebellum - and is commonly due to alcohol damage; the patient has an anterior- posterior sway with a frequency of 3Hz; the patient rarely falls because the body tremor is opposite in phase in head, trunk, and legs, resulting in minimal shift of the center of gravity)

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemap - Low back pain

Click on any of the headings or subheadings to rapidly navigate to the relevant section of the guidemap

Introduction

History of the present illness

● "red flags" suggesting potentially serious pathology

Examination

Diagnostic testing

● plain film X-rays of the lumbar spine

● bone scan

● CT scan of the lumbar spine

● MRI of the lumbar spine

● blood tests

● post-void urinary catheterisation and urinalysis

Medical decision-making

Appendix

● sensory dermatomes

● motor testing

● grading of motor strength

● simplified screening evaluation of a patient with sciatica

● straight leg raising test

● non-discogenic causes of sciatica

● Wadell's criteria

● differential diagnosis of back pain in ED patients

● clinical clue table

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Introduction

- although the majority of patients who present to the ED with low back pain have a self- limited back strain or an acute exacerbation of a chronic-back-pain syndrome, an EP should always use a consistently methodical (? step-wise) diagnostic approach that specifically considers, and excludes, potentially serious pathology so as to avoid "missing" a serious cause of low back pain

- this guidemap is tightly focused on the "red flag" approach to a patient with low back pain - to ensure that serious causes of back pain are considered, and diagnosed, during the ED visit

- this guidemap does not discuss the management/treatment of diseases that cause low back pain - it merely offers a diagnostic algorithmic approach to the ED evaluation of low back pain

- this guidemap does not contain any information on the diagnostic evaluation of less serious musculoskeletal causes of low back pain, and the reader should consult EM textbooks and other informational resources for further details about how to use a pattern- recognition approach to diagnose those entities

History of the present illness

- it is important to first determine when the low back pain started, how abruptly the pain started, and whether there were any precipitating postural factors, and/or sudden twisting movements, and/or weight-lifting elements at play at the time of onset of the back pain

(* sudden pain in the low back temporally related to heavy lifting - especially a rotational movement with the patient holding a heavy object away from the central axis of the body in a long-levered postural position - is most likely due to benign musculoskeletal pathology or a herniated disc; minor twisting body movements may be a precipitating factor in disc herniations and it may even produce a compression fracture in elderly or osteoporotic or chronic steroid-dependent patients, or it may be a "red herring" phenomenon that has no real etiological relationship to the sudden back pain)

- low back pain that is distinctly worse (or better) when assuming a certain posture or peforming a certain movement suggests a musculoskeletal etiology; while a writhing or restlessly pacing patient, who cannot get comfortable and who does not want to remain still, should be presumed to have back pain of non-musculoskeletal etiology eg. renal or biliary colic, a distending or leaking or rupturing AAA http://www.homestead.com/emguidemaps/files/backpain.html (2 of 25)8/20/2004 5:14:45 PM backpain

● low back pain that is worse when sitting or standing for prolonged periods or after prolonged riding in a car, or worse when coughing or sneezing or performing a valsalva maneuver suggests a herniated lumbar disc ● low back pain that is worse when walking (especially when going down stairs with a hyperextended posture) and that is rapidly relieved by rest (especially in a position of lumbar flexion) suggests spinal stenosis ● non-specific low back pain that is associated with morning stiffness and limited ROM and that improves later in the day suggests a rheumatological condition eg. ankylosing spondylitis - especially if the patient is a male between 30 - 40 years of age + there are other suggestive symptoms such as sacro-iliac/knee/foot pain +/- associated enthesopathies (plantar fascia, achilles tendon) ● acute onset low back pain that is distinctly worse with any back or torso movements, or that is associated with a poor tolerance for remaining in one position for prolonged periods, suggests local musculoskeletal pathology ● unrelenting low back pain, that is worse when supine or at night while at rest, is a "red flag" suggesting a malignancy or infection - especially if it has been present for more than a few weeks

- determine exactly where the pain is situated, whether the pain is very localised or diffuse, and whether it radiates to the buttocks or thighs or abdomen or below the knees

● pain that is very localised to the lumbar spine, especially if it is worsened by local palpation/percussion or axial loading, suggests potentially serious spinal pathology eg. fracture or infection or neoplasm ● pain that is diffusely located across the lower back, or that diffusely radiates to the buttocks and thighs, is non-specific and could be due to a multitude of non-serious or serious diseases ● pain that radiates below the level of the knees suggests sciatica - especially if it has a dermatomal distribution ● pain that radiates to the abdomen, or when abdominal pain is actually the major complaint, suggests the possibility of intra-abdominal pathology eg. renal or biliary colic, distending/leaking AAA, pancreatitis, perforating PUD, ovarian or tubal pathology, other retroperitoneal pathology eg. retroperitoneal infection or bleeding

- determine whether the patient has a history of similar pain and whether the etiology of the pain had been previously established (and by what means - CT scan or MRI), and whether the present back pain episode is identical to the previous episodes of back pain

(* if the character of the back pain + it's pattern of radiation + its associated/aggravating

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- in patients with chronic low back pain => determine the functional limitations of the patient and the analgesic drug use pattern

- specifically inquire about the presence of any of the following "red flags" suggesting potentially serious lumbo-sacral spine (or other) pathology

Red flags suggesting potentially serious lumbosacral spine (or other) pathology

● sudden onset of severe back pain, +/- abdominal pain, in an adult > 60 years (? symptomatic AAA) ● "colicky" pain associated with visceral functional symptoms, or "writhing" pain behaviour ● severe, unrelenting back pain that is worse when supine, and/or worse at night preventing sleep, and/or resistant to postural modification or high dose narcotic analgesics ● persistent, unremitting back pain of any type (> 6 weeks duration) ● any new neurologic deficits (lower extremity weakness or paralysis, saddle anesthesia and decreased anal sphincter tone, lower limb sensory loss or numbness, urinary retention or overflow incontinence, rectal obstipation or incontinence, erectile dysfunction) ● bilateral neurologic deficits or neurologic deficits involving multiple root levels ● any previous history of cancer ● any history of unintentional weight loss (> 10 lbs in 3 months) ● any history of fever or night sweats ● any history of an immunocompromised state, immunosuppressive drug or chronic steroid use ● any history of IV drug abuse ● any history of a bleeding diathesis or anticoagulant drug use ● any known AAA or previous aortic graft surgery ● any known underlying bacterial infection eg. pyelonephritis ● any known valvular heart disease, valve replacement surgery or a previous history of endocarditis; any new-onset heart murmur +/- fever ● any known active PUD/pancreatitis ● any recent major trauma or penetrating trauma

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● any recent spinal anesthesia or spinal tap ● any recent back surgery

- inquire about gastrointestinal and urinary symptoms and gynecological symptoms that may suggest non-spinal (intra-abdominal) pathology

(* do not automatically presume that the combination of suprapubic discomfort, urgency and urinary frequency implies cystitis; suprapubic pain could be due to bladder spasms, which are secondary to an early epidural compression syndrome, and the combination of suprapubic discomfort + urinary urgency + decreased urinary stream may reflect early bladder nerve compression, which may precede the development of frank urinary retention in patients with an early epidural compression syndrome)

- a psychosocial history is often necessary if the patient has a history of recurrent back pain and multiple ED visits, or a history of "doctor-shopping"

Examination

- check the vital signs for cardiovascular instability (suggests a leaking AAA) or a fever (suggests infection or malignancy or a rheumatological disorder)

- emaciation suggests an underlying malignancy or an immunocompromised patient

- examine the skin in all febrile patients for evidence of a source infection eg. cellulitis, "skin-popping" abscess

- examine the heart and lungs prn if mid-upper back pain is present (possible PE or AMI or aortic dissection), or if endocarditis or pneumonia or an underlying malignancy is suspected

- examine the abdomen in all patients > 50 years of age for evidence of a pulsatile mass, bruits and weak/missing femoral pulses

(* an abdominal exam has a low sensitivity for an AAA, and the triad of abdominal pain + pulsatile mass + shock is found in < 25% of cases; diminished femoral pulses are rare and distal pulse deficits secondary to peripheral emboli from an intramural thrombus is an even more rare physical finding)

- examine the abdomen of all patients, who have a history of associated abdominal pain (or prominent abdomino-pelvic visceral symptoms) for any abdominal tenderness or http://www.homestead.com/emguidemaps/files/backpain.html (5 of 25)8/20/2004 5:14:45 PM backpain

masses

- a rectal exam is selectively indicated to check for rectal sphincter tone (if a cauda equina lesion is suspected), to check for a rectal/prostate carcinoma if an underlying malignancy is suspected, or to evaluate the prostate if prostatitis is suspected

- a pelvic examination is selectively indicated when pelvic pathology or an underlying malignancy is suspected

- inspect the back for any areas of redness or bruising or swelling or deformity or previous surgical scars

- palpate and percuss each vertebrae for point tenderness if the pain is localised to the spine or central back, or if infection/neoplasm is suspected

- limited ROM of the spine strongly suggests a musculoskeletal problem, but is of very little localising value

- check the ROM of the hip to exclude referred back pain secondary to hip pathology

- point tenderness over the ischial tuberosity or greater trochanter may be the only clues to localised bursitis

- perform a straight leg raising test in patients with a history suggestive of sciatica (lower limb pain that radiates below the knee)

(* see the appendix for details on how to perform and interpret the straight leg raising test)

- perform a brief/detailed neurological examination of the perineum and lower limbs - a scrupulous neurological examination is mandatory if there are any neurological symptoms, or any abnormal neurological signs, or if there are multiple risk factors for any pathology that can cause an epidural compression syndrome

(* a minimal screening neuro exam would include hip flexor strength (L2/3), knee extensor strength (L3/4), foot dorsiflexion strength and/or heel walking (L5), plantar flexion strength and/or toe walking (S1), knee reflex (L3/4), ankle reflex (S1), anterior thigh light touch sensation - both upper (L2) and lower (L3), medial foot sensation (L4), dorsum of the foot sensation - just proximal to the web space between the second and third toes (L5) and lateral foot border sensation (S1) +/- peri-anal sensation (S2-4) +/- rectal sphincteric tone (S2-4) => detailed light touch, pain/temperature and proprioceptive testing can be reserved for selective cases when there are neurological symptoms

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- palpate the distal pulses and check the capillary perfusion of the toes if the patient's clinical history suggests effort-claudication (when a patient complains of buttock/lower limb pain that is precipitated/aggravated by ambulating and relieved by rest)

(* clinical evidence of arterial insufficiency of the lower limbs suggests "vascular claudication" and may help differentiate that entity from "neurogenic claudication" secondary to spinal stenosis; patients with spinal stenosis also have increased pain when hyperextending the back for > 30 secs and significant pain relief when stooping; spinal stenosis patients may have no pain when exercising in a flexed position eg. riding an exercise bicycle, but they may have disproportionate pain when descending steep hills in a hyperextended position)

- perform a Wadell evaluation if the clinical history suggests non-organic disease

(* see the appendix for details on Wadell's criteria)

Diagnostic tests

Plain film X-rays of the lumbar spine

- are rarely indicated in patients with back pain of acute/subacute (< 4 weeks) onset unless there is a history of major trauma

- may be indicated as a cheap screening test in "red flag" patients with acute/subacute back pain + suspected spinal infection or tumor

(* however, plain film X-rays have a low sensitivity and cannot be used to exclude those possibilities => in the patient with multiple "red flags" other imaging studies, such as CT scan or MRI, are indicated even if the plain film X-rays are negative)

- the use of plain film X-rays to screen for spinal degenerative changes, congenital anomalies, spondylolysis, spondylolisthesis and scoliosis very rarely adds clinically useful information => the presence of degenerative changes rarely correlate with the presence of symptoms, while other abnormalities (transitional vertebrae, spina bifida occulta, increased/decreased lordosis, scoliosis) are found with equal incidence in symptomatic and asymptomatic individuals

- ? only an AP and lateral view are required; oblique and coned-down views offer little http://www.homestead.com/emguidemaps/files/backpain.html (7 of 25)8/20/2004 5:14:46 PM backpain

additional information

- indications for lumbo-sacral spine X-rays include:-

● history of major trauma ● history of minor trauma in elderly, osteoporotic, or chronic steroid-dependent patients ● suspicion, or presence, of malignancy or infection ● unexplained back pain in a patient > 50 years ● unexplained back pain > 6 weeks ● tuberculous patient with back pain ● possible ankylosing spondylitis ● ? marked discrete point tenderness over the lumbar spine ● ? radiculopathy involving more than a single dermatome

(* new-onset sciatica involving a single dermatome is not an indication for immediate lumbar spine X-rays because ~ 90% of cases are due to a herniated lumbar disc, which cannot be diagnosed by plain film X-rays => imaging studies can be deferred to the follow-up physician; multiple dermatome involvement suggests malignancy or infection or massive disc herniation and immediate imaging studies are indicated)

Bone scan

- moderate sensitivity for detecting spinal infection, tumor or occult fractures

- however, the specificity is low and a bone scan is probably best utilised as a screening test in a patient with a suspected occult fracture not visible on a plain film X-ray; or a bone scan + a sed rate can be used as a screening test in patients with suspected spinal metastasis or vertebral osteomyelitis

- no studies have compared the relative accuracy of a bone scan versus CT/MRI in the diagnosis of spinal infection or tumor or occult fractures

CT scan of the lumbar spine

- a CT scan's greatest utility is in fracture evaluation, or when vertebral osteomyelitis is suspected

- a CT scan is more useful than a MRI in defining bony details - especially the facet joints and posterior elements

http://www.homestead.com/emguidemaps/files/backpain.html (8 of 25)8/20/2004 5:14:46 PM backpain - a standard CT scan cannot be used to exclude an epidural compression syndrome - unless it is used in conjunction with myelography; and a CT scan + myelography is indicated if a MRI is not available, or if a MRI is contra-indicated, or the patient is claustrophobic and/or cannot lie supine for prolonged periods

MRI of the lumbar spine

- a MRI provides the greatest degree of accurate anatomical detail - especially of the contents of the vertebral canal - compared to other radiological imaging studies

- an emergent MRI is immediately indicated if there any symptoms or signs of an epidural compression syndrome, or when a cancer patient presents to the ED with progressive neurological signs, or if there is a high clinical suspicion of an epidural abscess or an epidural hematoma

- an emergent MRI may be limited to the lumbo-sacral spine if an epidural compression syndrome due to a herniated lumbar disc is suspected, but the MRI study should include the entire spine if malignancy or infection or an epidural hematoma is suspected

- a non-emergent MRI may be indicated in the cancer patient, who presents to the ED with back pain + stable neurological signs, but the MRI can usually be delayed a few days and be performed as an outpatient study

- an emergent MRI is not indicated to investigate sciatica in the absence of significant (multi-dermatome) neurological deficits => defer MRI testing and refer the patient to the appropriate specialist, or consult a neurosurgeon in equivocal cases

- a MRI is contra-indicated in patients with pacemakers, intracardiac wires or mechanical heart valves, some intracranial aneurysm clips, or when metallic intraorbital foreign bodies are present

Blood tests

- blood tests are usually of no diagnostic utility

- an elevated WBC is a nonspecific test, and it has a low sensitivity for infection

- an elevated sed rate is rarely useful when used in isolation, because it a very non- specific test that has a variable sensitivity for infection or malignancy

- a sed rate should probably be ordered when historical factors, or examination findings,

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(* a low sed rate should not be used to exclude spinal infection or malignancy if there is a strong clinical suspicion of disease)

- a serum calcium should only be ordered when there is a strong clinical suspicion of hypercalcemia or malignancy

Post-void urinary catheterisation and urinalysis

- determination of the post-void urinary residual volume is usually only warranted if there is a strong clinical suspicion of urinary retention and overflow incontinence due to spinal cord or cauda equina pathology => a post-void residual volume of urine > 100 cc suggests neurogenic urinary retention and overflow incontinence (determined by catherization, or non-invasively by ultrasound)

(* a negative post-void large residual volume test virtually excludes a cauda equina syndrome with a > 99.9% negative predictive value)

- the presence of microscopic hematuria is not really useful because a significant minority of renal colic patients do not have hematuria, and microscopic hematuria may be an incidental finding in patients with an AAA or spinal disease

- pyuria could be secondary to pyelonephritis, but it could also merely represent the primary source of a secondary spinal infection (eg. vertebral osteomyelitis), which is actually causing the back pain

Medical decision making

- an EP should use a step-by-step algorithmic process to first consider (and exclude) life- threatening or spinal cord-threatening pathology before considering (and excluding) less serious pathology

(* although the algorithmic process is described in a step-by-step manner, an EP should be thinking about all these steps simeultaneously when taking the history and examining the patient)

- the first step in the algorithmic process is to consider and exclude a distending/ leaking/rupturing AAA in all patients > 60 years of age - especially if the patient has severe, intractable pain +/- associated abdominal pain +/- marked autonomic changes or http://www.homestead.com/emguidemaps/files/backpain.html (10 of 25)8/20/2004 5:14:46 PM backpain hemodynamic instability

- clinical signs of a symptomatic AAA are highly unreliable, and a diagnostic workup is required if there is a high clinical suspicion of a symptomatic AAA

- an ultrasound is highly sensitive (~ 100%) in detecting the presence of an AAA, but it can rarely detect evidence of a leaking AAA or a small, contained retroperitoneal AAA rupture; an ultrasound also cannot assess the branch vessels or adequately evaluate the suprarenal aorta or thoracic aorta => an ultrasound is mainly used to screen patients at risk of an AAA

(* an ultrasound has the advantage that it can be readily performed at the bedside in an unstable patient, and it may also detect the presence of any free intra-peritoneal blood if an AAA has ruptured into the peritoneal cavity)

- a spiral CT scan of the abdomen should be ordered if there is a high clinical suspicion of a symptomatic AAA in a stable patient, because it can detect a subtle leaking aneurysm and it can also evaluate the status of the branch vessels

- the second algorithmic step (after considering the possibility of an AAA) is to consider the possibility of an epidural compression syndrome (due to tumor, infection, hematoma, or a massive disc herniation)

- an epidural compression syndrome should be suspected if the patient has definite neurological deficits suggestive of a cauda equina syndrome or a spinal cord syndrome

● lower limb sensorimotor neuro deficits ● saddle distribution sensory loss ● bowel incontinence or unexplained loss of rectal sphincteric tone ● urinary retention and/or overflow urinary incontinence ● impotence ● "soft" neurological signs involving more than one dermatome + clinical risk factors for an epidural compressive process (hematoma or infection or malignancy)

- it may be clinically possible to differentiate a lower spinal cord syndrome (conus medullaris syndrome) from a cauda equina sydrome - a spinal cord syndrome usually presents with early spastic bladder symptoms (urinary retention + spastic bladder spasms + secondary overflow incontinence) and the later development of motor deficits involving the large muscle groups of the lumbo-sacral area and proximal lower limbs (+/- flexor spasms and/or spastic paraplegic ataxia) + hyperreflexia + a positive Babinski response + sensory deficit below a certain dermatome level; while a cauda equina syndrome usually presents with lower motor neuron sensorimotor deficits specifically affecting the lower

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(* it is not always possible, or even necessary, to clinically differentiate a spinal cord syndrome from a cauda equina syndrome - because emergency neuro-imaging is required in all patients with new-onset neurological deficits)

- all patients with a suspected epidural compression syndrome should have an emergent MRI (or CT scan + myelography) + dexamethasone IV (10 mg if suspected, and 100mg if definite) before performing the MRI study

- after considering, and excluding, the possibility of an epidural compression syndrome, the third algorithmic step is to consider the possibility of a spinal infection (vertebral osteomyelitis, discitis, epidural abscess)

- a spinal infection should be suspected if the following risk factors are present:-

● immunocompromised patient (HIV patient, transplant patient, chemotherapy- treated cancer patient, diabetic patient, alcoholic patient) ● IV drug-abuser ● recent bacterial infection eg. pyelonephritis, endocarditis, cellulitis, pulmonary infection ● recent spinal surgery or spinal anesthesia or spinal tap or peri-spinal penetrating trauma ● unexplained fever, chills or night sweats ● marked point tenderness or percussion tenderness over the spine ● unremitting back pain, which is unrelieved by recumbency or rest ● persistent back pain > 6 weeks ● unexplained elevated sed rate

(* fever is less likely to be present in patients with vertebral osteomyelitis than in patients with an epidural abscess; unexplained fever in a back pain patient is a "soft" physical sign because ~ 2% of back pain patients have a coincidental fever)

- a patient with a suspected spinal infection should have a CBC + sed rate + blood cultures (x 2) + radiological imaging study of the lumbo-sacral spine

(* plain film X-rays have a low sensitivity for infection and are only useful for vertebral osteomyelitis of > 6 - 8 weeks duration; plain film X-rays are not useful for diagnosing discitis or an epidural abscess => an emergent CT scan myelogram or MRI are the radiological imaging modalities of choice)

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- after considering a spinal infection, the 4th algorithmic step is to consider the possibility of spinal malignancy (primary or secondary) involving the lumbo-sacral spine

- an underlying spinal malignancy should be suspected when the following risk factors are present:-

● age > 50 years, or < 18 years ● unexplained weight loss ● unexplained low-grade fever ● unremitting back pain that is worse when supine, worse at night + interferes with sleep, unresponsive to supra-normal analgesic doses ● persistent back pain > 6 weeks ● unexplained elevated sed rate

- there is no optimum approach to diagnosing a possible occult malignancy involving the lumbo-sacral spine - a plain film lumbo-sacral spine X-ray has a low sensitivity, but it is easy to order/perform in an ED setting; a CT scan (or MRI) has a higher sensitivity and higher specificity, but it does not necessarily have to be performed in the ED setting if there are no neurological signs, or other high-risk imperatives, present => it is appropriate to defer ordering a CT scan (or MRI) if the screening lumbar spine X-rays are negative => refer the patient to the primary care doctor (or appropriate specialist) for follow-up +/- further radiological imaging studies

- if a known cancer patient presents to the ED with back pain, immediate diagnostic studies are appropriate

● cancer patient + new onset/progressive neurological signs => manage as a suspected epidural compression syndrome => dexamethasone + emergent MRI (or CT scan + myelography) ● cancer patient + known single-limb/single-dermatome neurological signs that have been present for days-weeks (neither acute nor progressive) => plain film X-rays => dexamethasone + urgent MRI (within 24 hours) if the X-rays are positive; close followup with primary care doctor + MRI (in 3 - 5 days) if the X-rays are negative ● cancer patient + back pain + no neurological signs => screening plain film X-rays => consult a specialist if the X-rays are positive; close follow-up with primary care doctor +/- MRI in one week if the screening plain film X-rays are negative

- finally, in a patient with new-onset sciatica => consider neuro-imaging if the sciatica involves more than one dermatome (multi-dermatome sciatica), or if there are other "red flag" symptoms or signs suggesting serious pathology

http://www.homestead.com/emguidemaps/files/backpain.html (13 of 25)8/20/2004 5:14:46 PM backpain - the presence of sciatica implies a herniated disc, but > 10 % of sciatica cases are due to other pathology - foraminal stenosis, piriformis syndrome, extraspinal plexus syndrome, spinal stenosis, compressive intraspinal tumor/infection - and further workup may be required if these other entities are suspected, or if the sciatica does not resolve within 6 weeks, or if the sciatica progressively worsens during the interim time period, or if multiple dermatome involvement becomes apparent over time

(* see the appendix for a detailed list of causes of non-discogenic sciatica)

- consult a neurosurgeon if there is a strong clinical suspicion (or any evidence) of an epidural compression syndrome, a spinal infection, a spinal malignancy or multi- dermatome sciatica

- if there is no evidence of a leaking AAA, or an epidural compression syndrome, or a spinal infection, or a malignancy involving the lumbo-sacral spine, or multi-dermatome sciatica, or intra-abdominal or pelvic pathology => treat the patient empirically with parenteral analgesics prn => po analgesics + outpatient follow-up (if the patient responds adequately to parenteral analgesics + patient can ambulate + home situation is compatible with the patient's degree of functional incapacity)

(* 90% of patients with acute lumbosacral strain have resolution of their symptoms in < 6 weeks => further diagnostic workup may be warranted if the back pain does not resolve within that time period)

Appendix

Sensory dermatomes

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Motor testing

- there is no "pure" single nerve testing of the lower limbs

- some easy-to-remember combinations include:-

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● hip flexion - L 2, 3, 4 ● knee extension - L 3, 4 ● foot dorsiflexion - L 4, 5 ● 2nd - 5th toe dorsiflexion - L 5 ● 1st toe dorsiflexion - L 5 or S1 ● foot plantar flexion - S1 ● squeezing buttocks together (gluteus maximus) - S1 ● anal sphincter "tightening" - S2, 3, 4

- the knee reflex is L 3/4 and the ankle reflex is S1

(* although many textbooks/journal articles suggest that first toe dorsiflexion innervation is primarily from L5, other textbooks/journal articles suggest S1 as the major innervation=> because of this discrepancy in opinions, it is recommended that you use foot and small toe(s) dorsiflexion for L5 testing and plantar flexion of the foot for S1 testing)

Grading of motor strength

● 5+ = Normal ● 4+ = Slightly less than full power against resistance ● 4 = Able to overcome moderate resistance ● 4 - = Able to overcome mild resistance ● 3 = Able to accomplish full ROM against gravity ● 2 = Able to accomplish full ROM with gravity eliminated ● 1 = Only trace muscle contraction, may only be palpable ● 0 = Flaccid

Simplified screening evaluation of a patient with sciatica

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Straight leg raising test

- this test is only used to determine whether a patient with back pain, who also has a history of pain that radiates down the lower limb to below the level of the knee, has a high

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(* > 80% of patients with a positive straight leg raising test have sciatica)

- the purpose of the test is to stretch the sciatic nerve by elevating the lower limb => stretches the inflammed/compressed sciatic nerve => induces pain in the lower leg or foot

(* increasing back pain, or buttock pain, or thigh pain is of no diagnostic relevance when performing the test - it is important to specifically ask the patient whether he develops any pain below the level of the knees)

- start off by having the patient lie supine with his pelvis flat on the bed and in a neutral position

- elevate the leg by cupping your hand below the patient's heel and slowly elevate the leg with the knee locked in extension => ask the patient whether elevating the leg causes any pain in the leg/foot below the ipsilateral knee

- a positive test = pain felt below the ipsilateral knee between 30 - 70° elevation

(* pain felt below < 30° elevation cannot be sciatica, because the sciatic nerve in not sufficiently stretched at that low elevation level)

- if pain is felt below the knee in the opposite (symptomatic) leg while the ipsilateral (asymptomatic) leg is being raised => highly specific for sciatica of the opposite leg (crossed straight leg raising test) - although it is a very insensitive test

- the accuracy of the straight leg raising test can be enhanced by the following maneuvers:-

● when the patient feels pain on straight leg raising => lower the leg a few degrees => the pain should disappear (or lessen ) ● then dorsiflex the foot in that position (or compress the soft tissue in the popliteal fossa) => re-appearance of the pain (or aggravation of the pain) suggests sciatica - Lasegue's sign

- an alternative method of performing the straight leg raising test is to perform the sitting knee extension test => with the patient sitting on the edge of the table/stretcher with both hips and knees flexed to 90° => slowly straighten the one leg as if to evaluate the foot => patient adjusts posture by falling back (positive flip sign) => a positive test has the same significance as the supine straight leg raising test http://www.homestead.com/emguidemaps/files/backpain.html (18 of 25)8/20/2004 5:14:46 PM backpain

(* the straight leg raising is not a full-proof test for sciatica and there are other causes of a positive straight leg raising test - myogenic pain syndromes, tight hamstrings or injured calf muscles)

Non-discogenic causes of sciatica

Hip or gluteal region

● following recent hip arthroplasty or hip replacement surgery ● following dislocated or fractured hip ● acute external compression (coma, drug OD, prolonged sitting) ● lithotomy position eg. following vaginal delivery ● gluteal compartment syndrome ● iatrogenic following a gluteal injection ● piriformis syndrome

Thigh region

● femur fracture ● posterior thigh compartment syndrome ● deep penetrating thigh laceration

Hip or thigh region

● gunshot wound ● nerve infarction (vasculitis, arterial thrombosis, arterial bypass surgery, DM, postradiation) ● mass lesion (benign or malignant tumor, arterial aneurysm, myositis ossificans, abscess)

Wadell's criteria

- these criteria are used to evaluate a patient with probable non-organic back pain

- the more criteria that are present => the greater the likelihood that the back pain could be non-organic; and > 3 criteriae should suggest non-organic pathology

Tenderness

● superficial tenderness on light touch of the skin or simple rolling the skin of the

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Pain responses to simulation maneuvers

● pain on minimal axial loading (increased back pain with light pressure loading on the top of the head) ● increased back pain with simple passive rotation of the shoulders when the patient is standing upright

Distraction maneuvers

● inconsistent responses to the straight leg raising test, or positive straight leg raising test + negative sitting knee extension test

Regional disturbance

● weakness: generalised (non-anatomical weakness) with generalised giving-way behaviours, or cog-wheeling resistance when testing strength in the lower extremities ● sensation: non-dermatomal or stocking sensory loss

Over-reaction

● disproportionate pain responses ● exaggerated bracing posture with both upper limbs supporting the body weight while sitting ● clutching, or grasping at affected areas for > 3 seconds ● dramatic facial grimacing ● sighing with shoulders rising and falling

Differential diagnosis of back pain in ED patients

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Immediate threat to life

● AAA ● pulmonary embolism ● aortic dissection ● acute myocardial infarction

Immediate threat to spinal cord

● epidural hematoma ● epidural abscess ● epidural tumor ● massive disc herniation

Urgent threat

Cardiac

● endocarditis

Renal

● pyelonephritis ● perinephric abscess ● renal colic ● renal artery embolus or dissection

Abdominal and visceral

● perforated gastric ulcer ● pancreatitis ● acute cholecystitis ● retroperitoneal hematoma or abscess ● prostatitis

Gynecological

● ectopic pregnancy ● pelvic infection ● endometriosis ● ovarian pathology

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Vertebral

● unstable fracture ● osteomyelitis ● Pott's disease (TB of the spine) ● Tumor ● herniated disc ● discitis

Less urgent threat

● lumbosacral strain ● degenerative processes of spine and discs and facet joints ● spinal stenosis ● osteoporosis with compression fracture ● congenital kyphosis/scoliosis ● spondylolithesis ● inflammatory arthritis (ankylosing spondylitis, psoriatic arthritis, rheumatoid arthritis, Reiters syndrome, arthritis associated with inflammatory bowel disease) ● Scheurmann's disease (osteochondritis) ● Shingles ● Paget's disease

Clinical clue table Clinical clues Suggests Age < 10 years Discitis, tumor, tuberculous vertebral osteomyelitis, bacterial osteomyelitis, congenital disorders Age 10 - 18 years Spondylolysis, spondylolisthesis, Scheurmann's disease, oversue syndrome, tumor, herniated disc, vertebral osteomyelitis, ankylosing spondylitis Age > 50 years Malignancy, spinal stenosis, AAA

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Pain worse with movement Musculoskeletal - mechanical and certain postures; pain relieved by rest Pain worse with coughing, Herniated disc sneezing, straining at stool or in moving car Pain worse at rest, or pain Spinal infection or malignancy worse at night awakening patient from sleep, or unrelenting pain, or pain lasting > 6 weeks Pain worse with walking, Spinal stenosis especially in hyperextension and relieved by stooping or flexed posture Pain radiates to below the Sciatica knee Pain radiates to L4 nerve root compression syndrome anterolateral thigh and anterior knee Pain radiates to L5 nerve root compression syndrome posterolateral thigh, lateral calf, dorsum of foot, medial toes; difficulty walking on heels Pain radiates to posterior S1 nerve root compression thigh, calf, heel, sole of foot, lateral toes; difficulty walking on toes Pain worse in the am, pain Ankylosing spondylitis or other improves during the day inflammatory arthritis and with activity +/- morning stiffness Back pain radiating to the AAA, renal colic, primary intra- abdomen abdominal pathology Abdominal pain radiating to AAA, perforating PUD, cholecystitis, the back pancreatitis, renal colic Pain localised to the mid- Spinal hematoma, aortic dissection, upper back AMI, pulmonary embolism

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Pain localised to one side of Shingles, unilateral paraspinal back pathology, referred pain from abdominal or retro-peritoneal pathology Weight loss Malignancy, underlying immunocompromised state, tuberculosis Fever, chills, night sweats Spinal infection, spinal malignancy, acute transverse myelitis, bacterial endocarditis, inflammatory arthritis, connective tissue disease, referred back pain from retro-peritoneal or abdominal inflammatory pathology Genito-urinary symptoms Renal colic, pyelonephritis, peri-nephric abscess, prostatitis, early spinal cord compression syndrome Altered bowel habits Rectal malignancy, cauda equina or spinal cord syndrome, inflammatory bowel disease disease Vaginal discharge, pelvic Pelvic infection, secondary spinal pain infection History of conjunctivitis Reiters syndrome History of uveitis Ankylosing spondylitis, rheumatoid arthritis IV drug abuse Epidural abscess, vertebral osteomyelitis, endocarditis Alcohol abuse Epidural abscess, pancreatitis, perforating PUD Chronic corticosteroid use Immunosuppression, occult vertebral fractures Anticoagulants or bleeding Epidural or retroperitoneal hematoma diathesis Osteoporosis Occult vertebral compression fractures History of trauma Vertebral fracture, herniated disc, back strain History of known Vertebral metastasis, epidural malignancy metastasis, metastatic plexus lesions, carcinomatous meningitis, paravertebral tumor masses

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Recent penetrating trauma, Spinal infection LP or back surgery Hypotension and/or syncope AAA, ectopic pregnancy, sepsis Restless, writhing patient Colic - renal, biliary, ovarian torsion Skin rash Psoriatic arthropathy, endocarditis, connective tissue disease Skin cellulitis, skin popping Spinal infection Palpable tenderness of spine Spinal infection, spinal malignancy Limited ROM of spine Musculoskeletal spine - non-specific Limited ROM of hip Referred pain from hip pathology, or back pain secondary to pelvic tilt Tenderness over sacrum or Sacro-ileitis sacro-iliac joints Tenderness over ischial Ischiotuberal bursitis tuberosity Unilateral neurologic deficit Sciatica Bilateral neurologic deficit Epidural compression syndrome

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemap - Ataxia, incoordination and dysequilibrium

Click on any of the headings or subheadings to rapidly navigate to the relevant section of the guidemap

Introduction

Definitions and general principles

● ataxia

● dyssynergia

● dysmetria

● dysdiadochokinesis

● hypotonia

● nystagmus

● dysarthria

● tremor and titubation

Clinical evaluation and medical decision-making

● clinical clue table - differentiating vestibular, cerebellar and sensory ataxia

Appendix

● Romberg's test

● posterior circulation stroke syndromes

● cerebellar damage in chronic alcoholism

● causes of sensory ataxia

Introduction

- this guidemap is mainly focused on problems of ataxia and incoordination due to cerebellar disease, and it offers an emergency physician basic guidance on how to problem-solve clinical cases of ataxia and incoordination using elementary clinical knowledge and selective diagnostic testing

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- dysequilibrium is a loss of balance without an abnormal sensation in the head, occurring only when the patient is standing or walking; it disappears upon sitting down, and is often caused by disorders of the motor system

- when a patient presents to an ED with vague symptoms of incoordination, dysequilibrium and/or an inability to walk, it is imperative that an emergency physician perform a thorough clinical evaluation of the cerebellar system, so that he can optimize his chances of successfully problem-solving the clinical problem

Definitions and general principles

- some common symptoms of cerebellar disease include:-

● headache ● nausea and vomiting ● gait unsteadiness ● dizziness or postural insecurity ● double vision ● blurred vision ● limb clumsiness ● limb weakness (hypotonia) ● kinetic or postural tremor ● dysarthria

- although the most common signs of cerebellar disease include gait or limb ataxia, tremor, dysdiadochokinesis, dysarthria and nystagmus; additional signs may be present (eg. disturbances in eye movements - gaze palsies, defective smooth pursuit or rapid eye movements) and those signs can be overlooked if not deliberatedly sought

- signs of cerebellar disease include:-

● gait ataxia ● disturbed stance ● limb dysmetria ● limb dysynergia ● kinetic (intention) tremors ● dysarthria ● past-pointing ● excessive rebound ● impaired check ● dysdiadochokinesis http://www.homestead.com/emguidemaps/files/ataxia.html (2 of 23)8/20/2004 5:14:50 PM ataxia

● head tilt or titubation ● hypotonia ● nystagmus ● ocular dysmetria or ocular dysynergia ● gaze palsies

- midline cerebellar diseases usually produce disturbed gait and stance while sitting or standing or walking, titubation of the head or trunk, and oculomotor disturbances (impaired smooth pursuit, dysmetria of saccades, and nystagmus), while lateral cerebellar hemisphere diseases usually produce varying combinations of limb ataxia, hypotonia, impaired check and excessive rebound, dysdiadochokinesia, dysarthria, nystagmus and transient ipsilateral gaze palsies (limb ataxia is generally more marked in upper limbs than in lower limbs, in complex movements than in simple movements, and in fast movements than in slow movements)

Ataxia

Ataxia is fundamentally a disturbance of muscle incoordination, which is not the result of muscle weakness or loss of muscle tone, or the intrusion of abnormal muscle movements

- implicit in the definition of ataxia is the presumption that muscle strength is not impaired, or not sufficiently impaired, to cause muscle incoordination

- the ataxic patient has problems with the accuracy and organization of voluntary muscle actions, resulting in uncoordinated movements involving the trunk and/or limbs and/or speech and/or eye movements

- the incoordination consists of irregularities in the rhythm, rate, and amplitude of voluntary movements => voluntary movements become jerky and erratic

- cerebellar gait disturbances involve disturbances in stance and gait => see the gait disorders, drop attacks and frequent falls guidemap for further details

- ataxia may primarily involve the trunk (truncal ataxia) and the patient may not be able to sit or stand unsupported (astasia); truncal ataxia is usually due to midline cerebellar disease, and associated limb ataxia due to lateral cerebellar hemisphere disease may not be present

- incooordination of walking (gait ataxia) that is so severe that the patient cannot walk is called abasia, and the term astasia-abasia is used if the the patient's balance is so impaired that the patient cannot maintain his balance when either sitting or walking

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- persistent incoordination of the truncal axial musculature may produce body tilts, pelvic tilts or head tilts

- severe lower limb dysmetria and dysynergia (due to lateral cerebellar hemisphere disease) may rarely produce an inability to walk, and mimic cerebellar gait ataxia (due to midline cerebellar disease)

Dysynergia

Dysynergia is an inability to smoothly perform the elements of a movement in the appropriate space and the correct time, and errors in the speed and sequence of the component parts of a movement causes a breakdown of a multi-joint movement into its constituent parts

- a patient with dysynergia cannot complete a smooth motor act, and the motor act decomposes into a series of fragmented individual movements so that smooth movements becomes erratic and irregular

- dysynergia can also involve eye movements, so that smooth pursuit eye movements, which normally occur when the eyes track a slowly moving object moving across the field of vision, become disrupted and fragmented

- ocular dysynergia is best tested by asking the patient to follow the slow movement of a visual target across the visual field (eg. physician's finger held 18 - 36" in front of the patient's face and slowly and smoothly moved from one side to the other side, and up and down) => a failure of either eye to move promptly, or smoothly - "broken-up" or "catch- up" stepped pursuit eye movements - suggests ocular dysynergia

(* the examiner's finger must not move too fast because smooth pursuit performance decays with age, inattention, and use of alcohol or certain drugs)

- bidirectionally stepped smooth pursuit defects can suggest diffuse brain disease or drug intoxication (because both the cerebral cortex and cerebellum are involved in pursuit eye movements), while unidirectionally stepped pursuit defects suggests brainstem- cerebellar disease

- in brainstem-cerebellar disease the pursuit steps tend to be frequent so that the overall envelope of pursuit closely approximates the trajectory of the slowly moving visual target => only slight oscillation of the eye might be visible during smooth pursuit testing, while cerebral cortex lesions cause pursuit step defects that are large and poorly controlled and easily recognized

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Dysmetria

Limb dysmetria is an inability to place and position a limb correctly, in both range and direction, across the plane of more than one joint

- a dysmetric limb mainly has difficulties with the initiation and termination of limb movements, and a limb with terminal dysmetria often moves beyond the target (hypermetria), or fails to reach the target (hypometria) during a voluntary movement; hypermetria is more suggestive of cerebellar disease than hypometria

- past-pointing refers to terminal limb dysmetria, and can be seen during finger-nose testing with the upper arm abducted to 90 degrees => elbow movement is tested by asking the patient to sequentially touch his nose and then touch a target held about 18 - 36" directly in front of his face => upper limb hypermetria will cause the patient's finger to strike his face because the patient cannot control the amplitude of the elbow movement

- another test of past-pointing is Barany's pointing test => the patient is asked to hold both arms extended horizontally in front => the examiner's finger touches the patient's extended forefinger => the patient is instructed to move the arm downward and then upward again to exactly reach the examiner's finger => after a few practice trials with preserved vision, the patient is asked to repeat the procedure with eyes closed => failure to control the limb causing past-pointing suggests terminal dysmetria

- a limb with severe dysmetria may oscillate widely as corrective movements are made during the limb movement to correct for errors made during the original limb trajectory => the large oscillations may suggest a severe intention tremor, which is also commonly present in cerebellar disease

- lower limb dysmetria is tested by heel-knee testing in the supine position => the one leg is elevated and the heel is placed on the opposite knee => the heel is then run smoothly down the leg to the top of the foot

- severe leg dysmetria will cause the heel to overshoot and miss the knee, and/or oscillate widely as it runs down the leg to finally overshoot the foot in an uncontrolled manner

(* poor performance of the heel-knee test is not necessarily a sign of cerebellar disease, because it is a difficult test to perform - especially for frail elderly patients)

- limb dysmetria is usually due to disease of the cerebellar hemispheres and the most common pattern is for limb dysmetria to be present ipsilateral to the side of the cerebellar hemisphere lesion, but it can also be contralateral to the lesion => localization is not completely reliable

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- with diffuse or degenerative cerebellar disease, the dysmetria is bilateral with little right- left asymmetry

The failure to demonstrate abnormalities of cooordination when the patient is lying in bed should never be considered as excluding cerebellar disease, because gross gait ataxia - due to midline cerebellar disease or cerbellar tonsillar herniation - may still be present

- dysmetria can also involve the extraocular eye muscles, and voluntary rapid eye movements towards a fixed target in space can either overshoot the target (hypermetric saccade) or undershoot the target (hypometric saccade)

(* saccades are rapid eye movements by which we voluntarily shift the line of sight between objects of interest)

- ocular dysmetria is tested by asking the patient to suddenly look at a fixed object in space, and observing for symmetry of the rapid voluntary eye movements (saccades) => a dysmetric eye may overshoot the visual target (hypermetria) and then show a short series of corrective step-saccades back towards the target, or the dysmetric eye may undershoot the visual target (hypometria) and have to undergo a short series of additional "catch-up" step- saccades to fixate on the target

(* with ocular dysmetria, the eyes appear to transiently oscillate about the visual target with movements of progressively smaller amplitude as fixation is established; opsoclonus - also called saccodomania- refers to to a disturbance of conjugate gaze in which the eyes manifest frequent involuntary rapid saccadic movements of varying amplitude and direction and the "dancing eyes" of saccodomania, which can persist during sleep, suggest diffuse cerebellar disease eg. paraneoplastic cerebellar degeneration; ocular flutter refers to paroxysmal side-to-side movements of the eyes that can often accompany ocular dysmetria in patients with cerebellar disease)

- the most distinctive type of cerebellar ocular dysmetria involves saccadic overshoot, and is best seen when the patient returns his eye position to primary forward gaze after conjugate gaze deviation => the eye temporarily oscillates as the patient attempts to re- fixate his vision on a visual target directly ahead

- hypermetric saccades are near-pathognomonic for lesions of the midline cerebellum (fastigial nuclei and dorsal vermis), while hypometric saccades can also be found in other (non-cerebellar) posterior fossa disorders

- formal saccadic testing is best done by sitting opposite the patient and then i) verbally instructing the patient to look to the left and then to the right (observing for dysfunction of

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- patients with basal ganglia or frontal lobe disorders may show difficulty in initiating saccades in response to a verbal command or when self-paced, but saccades to suddenly appearing visual targets (eg. flickering of the examiner's fingers during testing of visually elicited saccades) can be normal

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- patients with cerebellar disease have abnormal saccades in response to all testing modalities (although the degree of abnormality may vary according to the modality of testing)

(* terminal ocular dysmetria causes jerky eye movements only at the end of a rapid voluntary eye saccade; by contrast, ocular dysynergia produces jerky eye movements continuously during a slow, smooth eye pursuit movement)

Dysdiadochokinesis

Dysdiadochokinesis refers to the fragmentation of rapid alternating muscle movements seen in cerebellar disease

- dysrhymokinesis refers to a disrupted rhythm of fine motor movements eg. finger or foot tapping

- dysdiadochokinesis is best tested by asking the patient to slap his thigh with the palm of his hand and then flipping the hand over to slap the thigh with the back of his hand, while the examiner listens for the regular smoothness of repetitive discrete slaps of the hand against the thigh and also observes the smoothness and rhythm of the repetitive wrist movements

- dysrhythmokinesis is best tested by asking the patient to attempt to play an imaginary piano in the air in front of his body and assessing the speed, smoothness, and regularity of rapid finger movements; or by asking the patient to tap his fingertips rapidly and smooothly against a tabletop while resting his palm on the table

- dysdiadochokinesis and dysrhythmokinesis - like limb dysmetria - is usually seen in diseases of the cerebellar hemisphere, and is usually ipsilateral to the side of the pathology

Hypotonia

- acute cerebellar hemisphere disease often produces diffuse hypotonia, which results in defective maintenance of posture; the hypotonia disappears in a few days or weeks

- unilateral hemisphere disease may produce ipsilateral limb hypotonia

- hypotonia may be detected by noting that the limbs can easily be displaced with little force, and that arm excursion during walking is increased

- patellar tendon reflexes become pendular, and the limb oscillates for a number of oscillations before stopping

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- changes in mucle tone are usually associated with impaired check and rebound, and these signs are elicited by having the patient extend the arms directly forward and keep them in one plane as the examiner taps the wrist with enough force to move the wrist slightly => exaggerated movements of the arm +/- slight oscillations suggest an impaired check and rebound phenomenon

(* another indication of impaired check is the inability to stop a strenuous contraction of a limb muscle eg. the examiner asks the patient to keep his arm flexed while the examiner attempts to straighten the arm while holding onto the wrist => the flexed forearm will strike the upper arm in an uncontrolled manner when the examiner suddenly releases the actively flexed forearm without warning)

Nystagmus

- the nystagmus in cerebellar disease can consist of many different types and be difficult to classify

- gaze-evoked nystagmus is the most common type of cerebellar nystagmus

- in gaze-evoked nystagmus the patient develops jerking eye movements on conjugate gaze to the side or vertically, with the fast component in the direction of eye movement and the slow phase towards the primary eye position

(* the amplitude of the fast component of the nystagmus is often greater with conjugate movement of the eyes towards the side of unilateral cerebellar pathology; however, strictly midline or diffuse cerebellar disease can also produce gaze-evoked nystagmus)

- sometimes the fast component of the nystagmus, that is evoked by conjugate deviation of the eyes, may suddenly change direction without any change in direction of the eyes (rebound nystagmus)

(* rebound nystagmus is very suggestive of cerebellar disease, but it is non-localizing and may even be seen in drug intoxications causing diffuse cerebellar dysfunction eg. phenytoin intoxication)

- a transient rebound nystagmus may also occur when the patient returns his eyes to the primary gaze position, and the rapid phase of the nystagmus is opposite the side from which the gaze is directed (eg. the patient who has been looking to the left develops a transient nystagmus to the right when the eyes are returned to the primary forward gaze position)

http://www.homestead.com/emguidemaps/files/ataxia.html (9 of 23)8/20/2004 5:14:50 PM ataxia - gaze-paretic nystagmus, which is due to impaired central "gaze-holding" mechanisms, appears in lesions of the cerebellum or brainstem-cerebellar connections when the patient is looking in the same direction as the lesion, and has the same pattern as gaze-evoked nystagmus

- spontaneous downbeat vertical nystagmus or upbeat vertical nystagmus in primary forward gaze can occur, and normal optokinetic nystagmus may be dampened or disrupted

(* downbeat nystagmus is usually seen with disorders affecting the cerebellum or cervicomedullary region, while upbeat nystagmus is usually seen in cerebellar vermis lesions or intra-axial midline brainstem lesions)

- other more bizzare forms of nystagmus can also be seen eg. periodic alternating nystagmus, pendular nystagmus, divergent nystagmus, pure torsional nystagmus on vertical gaze

(* see the nystagmus guidemap for more details on nystagmus)

- gaze apraxia (problems re-directing gaze with normal extraocular apparatus function) is seen in certain hereditary ataxic syndromes, and the patient has to turn his whole head to drag his eyes onto a visual target

- gaze paresis can occur with cerebellar lesions, but it more commonly reflects an expanding posterior fossa lesion and secondary abducens nerve compression

- skew deviation of the eyes (one eye higher than the other eye on primary forward gaze, or eccentric gaze) can also be seen in cerebellar disease

- an inability to suppress the vestibulo-ocular reflex (VOR) is often present in cerebellar disease, and the VOR is tested by asking the patient to elevate the arms in front of him and fixate one thumb while slowly rotating the upper body; the normal subject can maintain fixation and the eyes do not drift away from the point of fixation during movements of the head relative to the body

Dysarthria

- cerebellar dysarthria is usually of the spluttering-staccato type

- cerebellar spech is usually slow and slurred with unusual rhythms, and has inappropriate emphases of pitch and loudness, and articulatory impreciseness

http://www.homestead.com/emguidemaps/files/ataxia.html (10 of 23)8/20/2004 5:14:50 PM ataxia - if the speech becomes so disturbed in rhythm and emphasis that it becomes unintelligible, it is referred to as scanning speech

- cerebellar dysarthria is thought to be due to pathology of the left paravermal zone of the cerebellum

- poor penmanship often accompanies cerebellar dysarthria and writing requires excessive concentration

Tremor and titubation

- both static and kinetic tremors occur with cerebellar damage and much of the amplitude of the tremor may arise from instability of the proximal muscles of the involved limb

- the most common cerebellar tremor is a side-to-side kinetic tremor that worsens when the limb approaches the target (intention tremor)

- titubation usually refers to the head, and the rhythmic oscillations may be side-to-side, or forward-and-back or even rotatory

- the titubation may also affect the trunk

(* see the tremor guidemap for more information on cerebellar and other tremors)

Clinical evaluation and medical decision-making

- the history-taking and physical examination should primarily be geared towards differentiating cerebellar ataxia from the two other common causes of ataxia - sensory ataxia and vestibular ataxia

- the clinician should search for clinical clues that may suggest a particular pathophysiology, so that he can at least determine the likely topographic diagnosis (site of the pathology)

Clinical clue table - differentiating vestibular, cerebellar and sensory ataxia History/exam Vestibular Cerebellar Sensory

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Vertigo ● present ++ if the ● sometimes ● absent vestibulopathy is present acute and ● less intense unilateral ● constant ● often intense and ● unaffected by disabling head ● paroxysmal, movements constant, or waxing and waning ● may be worse with head movements, +/- noise, or Valsalva maneuvers

Deafness, tinnitus ● may be present ● uncommon ● absent

Associated nausea, vomiting ● often present if ● may be ● absent and diaphoresis acute present ● prominent and ● less severe prominent and less severe

Limb paresthesia or ● absent ● may be ● present numbness present with brainstem involvement

Ataxia worse in the dark ● only if bilateral ● absent or rare ● present vestibulopathy

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Cerebellar signs ● absent ● present ● absent

● tremor ● ataxia ● dysmetria ● dysynergia ● dysdiadochokinesis ● dysarthria ● titubation ● impaired eye pursuit ● impaired saccades ● gaze palsies ● skew deviation

Nystagmus ● often present ● often present ● absent acutely ● central type ● peripheral type

Peripheral proprioceptive ● absent ● absent ● present sensory deficit

Romberg's test ● may be present ● absent ● present if there is a bilateral vestibulopathy

(* see the nystagmus guidemap for much greater detail on differentiating peripheral from central nystagmus; see the appendix for details on Romberg's test)

- after completing a neuro-otological examination, it should be possible to decide whether the ataxic patient has clinical signs to suggest a gait ataxia due to cerebellar disease, vestibular disease or proprioceptive sensory loss disease

- if the ataxic patient does not have any abnormal cerebellar signs or a cerebellar ataxic gait, or severe vertigo or peripheral nystagmus or deafness suggestive of vestibular disease, or evidence of proprioceptive loss in the lower limbs suggestive of sensory ataxia => specifically look for signs of basal ganglia disease, frontal lobe disease, hydrocephalus, or UMN pathology

- if the patient has an ataxic gait disorder, the presence of altered muscle tone (rigidity), bradykinesia, rest tremor, and/or spasticity, and/or urinary incontinence and/or http://www.homestead.com/emguidemaps/files/ataxia.html (13 of 23)8/20/2004 5:14:50 PM ataxia

dementia suggests the possibility of an extra-pyramidal syndrome, frontal lobe lesion, normal pressure hydrocephalus or upper motor neuron lesion => see the gait disorders, drop attacks and frequent falls guidemap for further problem-solving information

- if the symptoms and signs suggest cerebellar disease, the likely etiology depends on whether the clinical presentation is acute or chronic, and whether the pattern of cerebellar signs suggests midline cerebellar pathology, cerebral hemisphere pathology, or diffuse cerebellar pathology

- midline cerebellar pathology affecting the flocculonodular lobe often produces the following combination of signs

● unsteadiness of gait and stance when sitting or standing or walking ● severe truncal ataxia + no incoordination of the extremities while in bed ● postural sway is omnidirectional, and visual stabilization of posture is absent (absent Romberg's sign) => severe postural sway is present even with the eyes open ● dysarthria +/- ● impaired saccadic slow pursuit eye movements ● gaze-evoked, rebound, and downbeat nystagmus; impaired optokinetic nystagmus ● inability to suppress the VOR ● fine coordinated limb movements are relatively well preserved

- anterior lobe (spinocerebellum) pathology - seen most commonly in chronic alcoholics - often produces the following combination of signs:-

● severe disturbance of standing and walking with relatively preserved fine coordinated movements of the upper limbs ● anteroposterior body sway of 3Hz ● visual stabilization of posture is preserved and closing the eyes increases the body tremor (presence of Romberg's sign) ● patient rarely falls because the body tremor is opposite in phase in the head, trunk and legs resulting in minimal shift in the center of gravity ● dysarthria + ● impaired dysmetric saccades

- unilateral cerebellar hemisphere pathology often produces the following combination of signs:-

● severe ipsilateral limb ataxia (dysmetria and dysynergia) ● ipsilateral deviation of gait ● ipsilateral hypotonia (if acute) ● ipsilateral dysdiadochokinesis

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● ipsilateral past-pointing ● dysarthria ++ (if left hemisphere) ● nystagmus +/- ● ocular dysmetria +/-

- bilateral cerebellar hemisphere and vermis pathology often produces the following combination of signs:-

● bilateral limb ataxia + ataxia of stance and gait ● dysarthria ++ ● multiple oculomotor disturbances (nystagmus, ocular dysynergia, ocular dysmetria and gaze palsies) ● extra-cerebellar signs (pyramidal and extra-pyramidal)

- some common causes of acute cerebellar disease that one should consider:-

● drug intoxications (phenytoin, isopropyl alcohol, ethanol, carbamazepine, barbiturates, lithium, phencyclidine) ● volatile solvents (toluene, gasoline-additives) ● heavy metals (lead, manganese, mercury, thallium) ● cerebellitis (recent viral infection - varicella, mumps, infectious mononucleosis; bacteria, HIV) ● acute disseminated encephalomyelitis (recent immunisation or recent viral infection) ● Wernicke's encephalopathy (altered LOC, external ophthalmoplegia, ataxia, nystagmus) ● vertebro-basilar artery insufficiency ● vertebral artery dissection ● cerebellar hemorrhage or cerebellar infarction ● Miller-Fisher variant of Guillane-Barre syndrome (ataxia, external opthalmoplegia, areflexia) ● trauma (primary cerebellar trauma, subdural or epidural hematoma in the posterior fossa)

- some common causes of chronic cerebellar disease that one should consider:-

● alcoholic cerebellar degeneration (history of chronic alcohol use) ● phenytoin-induced cerebellar degeneration (history of chronic phenytoin use) ● multiple sclerosis (suggested by recurrent and multi-focal neuropathology) ● hypothyroidism (signs of myxedema - cold, dry skin and hair loss) ● paraneoplastic cerebellar degeneration (history of known malignancy, unexplained weight loss or cachexia) ● cancer patients taking cytosine arabinoside or 5-fluorouracil (causes cerebellar degeneration) http://www.homestead.com/emguidemaps/files/ataxia.html (15 of 23)8/20/2004 5:14:50 PM ataxia

● hereditary spinocerebellar ataxias ● rare metabolic diseases (Hartnup disease, maple syrup urine disease, pyruvate carboxylase deficiency) ● Friedrich's ataxia (pes cavus, kyphoscoliosis, cardiomyopathy, posterior myelopathy, peripheral neuropathy, extensor plantar responses, spasticity, optic neuropathy) ● ataxia-telangiectasia (choreo-athetosis, loss of leg proprioception, areflexia, mental retardation, skin and conjunctival telangiectasia) ● Wison's disease ● acquired hepatolenticular degeneration ● Creutzfeldt-Jacob disease ● posterior fossa tumor (eg. medulloblastoma in children) ● posterior fossa malformations (eg. Arnold-Chiari malformation)

- some common causes of episodic ataxia that one should consider:-

● multiple sclerosis ● transient vertebrobasilar ischemic attacks ● foramen magnum compression (Arnold-Chiari malformation) ● intermittent obstruction of the ventricular system ● dominantly inherited periodic ataxia

- there is no full-proof method of coming to a particular clinical diagnosis solely on the basis of the clinical presentation => a physician should consider the list of possible diagnoses, and look for historical elements that favor the likelihood of certain diagnostic possibilities

- certain clinical patterns may also suggest a likely diagnosis - localised cerebellar involvement (eg. unilateral cerebellar hemisphere involvement) suggests localised cerebellar pathology (eg. tumor or abscess or hemorrhage); while pancerebellar involvement suggests a disease causing diffuse effects (eg. drug intoxication if symptoms are acute; hereditary cerebellar degenerative disease or paraneoplastic cerebellar degeneration if the symptoms are subacute or chronic)

- the presence of a positive Romberg's test + polyneuropathy in an acutely ataxic patient, who also has definite cerebellar signs => suggests a combined cerebellar + polyneuropathy disorder, due to volatile solvents used in industry and by drug addict "huffers"; or multifocal neurological disorders like multiple sclerosis and Friedrich's ataxia if the presentation is less acute

- the combination of acute ataxia + myelopathy + altered LOC suggests an acute disseminated encephalomyelitis secondary to recent infection or immunization; the combination of myelopathy + peripheral neuropathy + ataxia suggests Friedrich's http://www.homestead.com/emguidemaps/files/ataxia.html (16 of 23)8/20/2004 5:14:50 PM ataxia ataxia

- the combination of cerebellar ataxia + neuropathy + pyramidal signs + extrapyramidal signs + cognitive defects suggests a cerebellar degenerative disorder

- the presence of an acute cerebellar syndrome + acute brainstem signs suggests a posterior circulation stroke syndrome, or rapidly expanding posterior fossa lesion eg. bleed into a cerebellopontine angle tumor

(* pure cerebellar lesions do not cause disturbances in sensation; crossed sensory disturbances with a loss of pain sensation on one side of the face and on the opposite side of the body are common in patients with a brainstem lesion; involvement of the brainstem is also suggested by signs such as dysphagia due to lower cranial nerve involvement, facial nerve palsies, Horners syndrome, vertigo +/- hearing loss, and pyramidal long tract signs => see the appendix for further details on different patterns of posterior circulation stroke syndromes)

- the presence of an acute cerebellar syndrome + acute headache + altered LOC suggests a rapidly expanding posterior fossa lesion (eg. cerebellar hemorrhage, bleeding into a cerebellar tumor, third ventricle cyst + obstructive hydrocephalus) and/or cerebellar tonsillar herniation => an immediate MRI or CT scan is indicated

- a history of subacute headache that is worse in the morning, and on bending and coughing + subacute ataxia => suggests increased intracranial pressure due to posterior fossa pathology => MRI or CT scan indicated

(* the headache associated with a slowly expanding posterior fossa mass can be located in the occipital area or anteriorly behind the eyes)

- a diagnostic workup in the ED for a stable patient with an acute cerebellar syndrome can be initiated following consultation with a neurologist, and the workup may include blood tests (including heavy metals, serum ETOH and anticonvulsant drug levels), neuroimaging to exclude posterior fossa lesions, and CSF examination to exclude viral lymphocytic meningoencephalitis or acute disseminated encephalomyelitis - depending on the particular clinical features of the patient's clinical presentation

- chronic alcoholic patients may develop gait ataxia due to a variety of reasons (70% of cases are due to diffuse cerebellar degneration), and it is difficult to sort out the likely cause of the ataxia => see the table of cerebellar damage in chronic alcoholism for guidance

- the presence of ataxia + any of the following signs suggests a genetic disorder

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● developmental delay ● episodic alteration in consciousness ● recurrent neurological symptoms ● associated movement disorders or seizures ● sudden episodes of ataxia precipitated by startle, emotions or movement ● family history of similar symptoms in a sibling or close relative ● neurologic or developmental regression ● skin lesions or rashes, or musculoskeletal abnormalities ● multi-system involvement (in addition to the CNS)

Appendix

Romberg's test

- the test is primarily used to differentiate sensory ataxia from cerebellar ataxia

- Romberg's sign detects proprioceptive sensory loss by demonstrating loss of postural control in darkness

- the test is usually performed by having an examiner observing the patient's postural stability when standing with the feet close together, initially with eyes open and then with eyes closed

- Romberg's sign is present when a patient is able to stand with feet together and eyes open, but sways or falls with the eyes closed

- the test is classically positive in patients with proprioceptive loss because they are dependent on visual cues to remain in a state of postural equilibrium; however, patients with bilateral vestibular damage are also dependent on visual cues for balance and they may also have a positive Romberg's sign

- some patients* with cerebellar ataxia also have a positive Romberg's sign and they are also dependent on visual cues for maintenance of postural balance while standing

(* the pathology lies in the anterior vermis and paravermis of the anterior lobe - spincocerebellum - and is commonly due to alcohol damage; the patient has an anterior- posterior sway with a frequency of 3Hz; the patient rarely falls because the body tremor is opposite in phase in head, trunk, and legs, resulting in minimal shift of the center of gravity)

Posterior circulation stroke syndromes

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- ischemic strokes involving the cerebellum often involve the brainstem, because the arteries supplying the cerebellum also supply the medulla and brainstem

- the different stroke patterns are very difficult to remember, and the following information may be used as a "memory-jogging" aid if the need arises

Superior cerebellar artery occlusion

5 distinct clinical patterns are seen

Classic SCA syndrome

- rarely seen

● ipsilateral limb dysmetria ● ipsilateral Horner's syndrome ● contralateral pain and temperature loss ● contralateral 4th cranial nerve palsy ● ipsilateral loss of emotional expression in the face ● unilateral or bilateral hearing loss ● ataxia ● +/- choreiform or athetoid movement disorders ● +/- coarse tremors

Rostral basilar artery syndrome

- occurs in 25% of cases of SCA occlusion

- some of the following clinical features may be present

● visual field defect, vomiting, dizziness, dipoplia, limb clumsiness, weakness, paresthesia, drowsiness ● +/- cortical blindness, memory loss or confusion, paralysis of visual fixation (Balint's syndrome) ● multimodal sensory loss ● contralateral Horner's syndrome ● ipsilateral hemianopia ● appendicular ataxia ● abulia, behavioural changes ● unilateral spatial neglect ● memory loss ● transcortical motor aphasia http://www.homestead.com/emguidemaps/files/ataxia.html (19 of 23)8/20/2004 5:14:50 PM ataxia

● vertical gaze palsy ● third nerve palsy + contralateral limb movement disorder (Benedikt's syndrome) ● third nerve palsy + contralateral limb dysmetria (Claude's syndrome) ● third nerve palsy + contralateral limb weakness (Weber's syndrome) ● +/- pseudo sixth nerve palsy, tonic deviation of gaze, palpebral retraction, pupillary disturbances, drowsiness, hallucinosis, confusion, ipsilateral Horner's syndrome, contralateral pain and temperature loss, internuclear ophthalmoplegia

Coma from onset + tetraplegia + oculomotor palsy

- due to embolic obstruction of the rostral end of the basilar artery

Cerebellovestibular syndrome

- due to partial SCA territory involvement

● headache, gait difficulty, dizziness, vomiting ● appendicular ataxia ● gait ataxia ● nystagmus ● dysarthria ● some brainstem signs

LSCA syndrome

- due to anterior-rostral cerebellar involvement

- may mimic the dysarthria-clumsy hand lacunar syndrome

● ipsilateral limb dysmetria ● ipsilateral axial lateropulsion and gait unsteadiness ● dysarthria

Anterior inferior cerebellar artery occlusion

- exceedingly rare

- 4 distinct clinical pictures

Classic AICA syndrome

- often mistaken for a lateral medullary syndrome; however, certain signs are unusual in http://www.homestead.com/emguidemaps/files/ataxia.html (20 of 23)8/20/2004 5:14:50 PM ataxia lateral medullary syndrome (facial palsy, deafness, tinnitus, multimodal sensory impairment over the face)

● vertigo, vomiting, tinnitus, speech difficulty ● ipsilateral facial palsy ● ipsilateral 5th cranial nerve sensory loss ● ipsilateral Horner's syndrome ● ipsilateral appendicular dysmetria ● contralateral pain and temperature sensory loss over trunk and limbs ● +/- ipsilateral conjugate gaze palsy, dysphagia, ipsilateral limb weakness

Coma with tetraplegia

- due to massive ventromedial involvement of the basis pons together with cerebellar infarction in the territory of all three cerebellar arteries

Isolated vertigo

- mimics acute labyrinthitis

Isolated cerebellar signs

- variable cerebellar signs

Posterior inferior cerebellar artery occlusion

- the PICA supplies the cerebellum and dorsal and lateral medulla

- three distinct clinical syndromes

Dorsal lateral medullary syndrome

- Wallenberg's lateral medullary syndrome may be complete or incomplete

● vertigo ● nystagmus ● 5th, 9th and 10th cranial nerve palsies ● ipsilateral Horner's syndrome ● appendicular ataxia ● contralateral pain and temperature loss ● ocular dysmetria, dysynergia and palsies

http://www.homestead.com/emguidemaps/files/ataxia.html (21 of 23)8/20/2004 5:14:50 PM ataxia PICA strokes that spare the medulla

● vertigo, headache ● gait ataxia ● limb ataxia ● horizontal nystagmus ● ipsilateral axial lateropulsion

Isolated vertigo

- mimics labyrinthitis and presents with vertigo and ataxia

- clinical clues that suggest a posterior fossa stroke (rather than a peripheral vertigo syndrome) include age > 50, presence of vasculopathic risk factors, direction-changing nystagmus, and normal calorics

Cerebellar damage in chronic alcoholism Anterior Diffuse Wernicke lobe cerebellar encephalopathy atrophy degeneration Ataxia of stance +++ + +++ Ataxia of gait +++ + +++ Gaze nystagmus + ++ +++ Pupillary Normal Normal - responses Leg dysmetria +++ + + Arm dysmetria + ++ + Polyneuropathy (+) +++ + Cerebral atrophy (+) ++ (+) (CT) Hepatic - + - dysfunction Altered LOC - - +++

Causes of sensory ataxia

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Polyneuropathy

● autosomal dominant sensory polyneuropathy ● ciplatinin ● diabetes ● diptheria ● hypothyroidism ● immune-mediated (GALOP syndrome, antiMAG antibody syndrome, Miller Fisher syndrome, antiGD1b antibody syndrome) ● isoniazid ● paraneoplastic sensory neuropathy (anti Hu antibodies) ● pyridoxine ● Refsum's disease ● taxol

Myelopathy

● acute transverse myelitis ● AIDS myelopathy ● multiple sclerosis ● tumor ● epidural compression syndrome ● vascular malformations

Polyneuropathy or myelopathy

● Friedrich's ataxia ● tabes dorsalis ● vitamin B12 deficiency ● vitamin E deficiency

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra- indications, prior to their use.

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EM guidemap - Spinal cord syndromes

Introduction

Spinal cord anatomy and topographical pathophysiology

● anterior cord syndrome

● central cord syndrome

● posterior cord syndrome

● Brown-Sequard syndrome

● inferior cord (conus medullaris) syndrome

● cauda equina syndrome

● syringomyelia

Clinical clues and clinical spinal cord syndromes

● differential diagnosis of spinal cord syndromes

Appendix

● motor testing

● grading of motor strength

● sensory dermatomes

● somatotopic anatomy of the spinal cord

● summary of the clinical features of some spinal cord syndromes

● evolution of chronic central cord syndrome

Introduction

- this guidemap offers simple clinical advice and basic pathophysiology algorithms that may help a clinician problem-solve spinal cord syndromes in an ED setting

- this guidemap provides no clinical information on diagnostic testing or the treatment of any spinal cord diseases; it is merely a basic guidemap that may help you improve your diagnostic skills in detecting spinal cord syndromes

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Spinal cord anatomy and topographical pathophysiology

- the spinal cord extends from the foramen magnum to the L1/2 level and pathology of the spinal cord mainly produces symptoms and signs due to the involvement of 3 main areas of the spinal cord - the dorsal columns, the spinothalamic tracts, and the corticospinal motor tracts

- the dorsal columns contain sensory tracts for crude touch, position sense and vibration sense; the lateral spinothalamic tracts contain sensory tracts for pain and temperature and light touch; and the anterior spinothalamic tract contains sensory tracts for touch and pressure

- the antero-lateral corticospinal tracts carry descending motor pathway fibres

Dorsal columns

- consist of sensory tracts carrying information about crude touch-pressure, two point discrimination, vibration and position sense to the brain - on the ipsilateral side of the spinal cord => the fibres cross to the opposite side at the level of the medulla

- crude touch fibres also cross the midline to enter the contralateral anterior spinothalamic tracts and dysfunction of the dorsal column may not produce a detectable disturbance in touch sensation => testing crude light touch sensation is a poor technique for localising spinal cord dysfunction and should not be used in the sensory examination as a discriminatory test

- vibration sense is also carried in several pathways and its absence cannot be regarded as specific evidence of dorsal column pathology http://www.homestead.com/emguidemaps/files/spinalcord.html (2 of 14)8/20/2004 5:15:00 PM spinalcord

- vibration sense testing is also potentially inaccurate with regards to unilateral or bilateral localisation when testing is performed along the central trunk (eg. pelvis, ribs and sternum), and some elderly patients normally have poor vibration sense perception

- testing joint position sense is the best test of dorsal column function - testing is usually performed by moving the DIP joints of the fingers and toes through a ~ 10 - 20° angle ROM (holding the finger along the sides of the middle and distal phalanges) => flexing/extending the ankles and wrists is only useful for detecting more gross deficits

- disease affecting the dorsal columns often produces unpleasant deep sensations and buzzing paresthesias or negative sensations of "deadness" and these symptoms often precede detectable abnormal sensory signs; the "deep" sensations are not necessarily of localising value and patients may often complain that parts of the neuro exam (eg, stroking the foot to elicit the plantar response or bending the digits to test position sense) are unusually painful or uncomfortable

- abnormal "deep" sensations include unpleasant vibrating paresthesias - like touching an electric typewriter, standing on the vibrating deck of a ship', tight band-sensations around the torso, bizarre perceptions of body image

Lateral spinothalamic tract

- pain and temperature fibres enter the spinal cord and then ascend a few spinal segments before crossing to travel up the contralateral lateral spinothalamic tract

- local pathology of the spinal cord affecting the spinothalamic tract will therefore produce a contralateral pain and temperature sensory deficit and there will be a difference of a few spinal dermatome levels between the level of detectable sensory deficit and the true level of spinal pathology

- temperature testing is rarely necessary (and is of poorer localising value because some temperature fibres are carried in the contralateral spinothalamic tract) and testing for pain sensation is the best method of assessing the function of the lateral spinothalamic sensory tract

- pain testing should be performed with a broken Q tip handle (or broken tongue blade) using the sharp pointed end of the splintered Q tip/blade to test for pain sensation (remember to specifically ask the patient whether he feels "pain" and not merely "touch"; the blunt end of the stick can be used for crude touch comparison testing)

- disease of the central cord can affect the pain-temperature sensory fibres crossing the midline anterior to the central canal and produce a unilateral or bilateral band of pain-temperature sensory deficit affecting a few dermatomes just below the level of the spinal cord lesion => this band of abnormal sensation can sometimes be unilateral and it may be opposite the side of the major pain-temperature sensory deficit if the spinal cord lesion eventually extends to affect the ipsilateral spinothalamic tract

- as sensory fibres cross the spinal cord and enter the spinothalamic tract they push the already-entered sensory fibres laterally => the sacral sensory fibres are therefore situated most laterally in the spinothalamic tract => central cord disease impinging on the spinothalamic tract in the cervical area may mainly affect pain-temperature sensation arising from the upper limbs and trunk and spare the sacrum => this pattern of sensory deficit can help localise a spinal cord lesion to the cervical central cord; also, never conclude that a spinal cord lesion is complete if sacral pain-temperature sensation is still present (sacral-sparing always suggests incomplete spinal cord pathology) http://www.homestead.com/emguidemaps/files/spinalcord.html (3 of 14)8/20/2004 5:15:00 PM spinalcord

(* see the appendix for a diagram of the somatotopic anatomy of the spinal cord)

- pathology affecting the spinothalamic tract often produces vague sensory symptoms (very deep, poorly localised pain of a nagging or boring quality) well before a detectable sensory deficit is present - the symptoms are "deep" unpleasant sensations and not sensations of numbness (when a patient complains of numbness - he is usually referring to the 'heavy' feeling associated with weakness and he is not usually referring to a true loss of sensation)

- these unpleasant symptoms may become more dramatic as time progresses and may suggest a psychological disorder to the unwary clinician

- the patient may also have a "loss of feeling" detectable on examination without the patient being previously aware of any sensory deficit

- sensory testing is fraught with potential misinterpretations because mild sensory deficits are difficult to distinguish from genuine physiological differences

- testing for a sensory level is more accurate when moving from an area with a sensory deficit to a normal area, than vica versa

Lateral corticospinal tract

- pathology affecting the upper motor neuron fibres travelling in the corticospinal tract produces an ipsilateral motor deficit

- chronic pathology affecting the corticospinal tract produces signs of an UMN lesion (spasticity + clonus + hyperreflexia + positive Babinski response) long before it produces detectable muscle weakness => the patient will complain of clumsy hand movements and tripping when walking over uneven ground or when trying to walk fast or break into a run - long before he has detectable muscle weakness on motor strength testing (loss of dexterity and "fatigueability" of movement precedes motor weakness); and physical examination may reveal spasticity chiefly affecting the flexors of the upper limbs and extensors of the lower limbs long before any overt weakness is apparent

- test for spasticity by asking the patient to play a piano in mid-air with the arms extended and observe the fluidity of his finger movements; and ask the patient to wiggle his toes fast and smoothly => clumsiness of movements suggests UMN pathology

- increased muscle tone in the upper limb can be tested by holding the patient's hand as if shaking hands, and then gently flexing and extending the elbows and wrists and then rotating the elbows by supinating-pronating the forearm => a slight "catch" may be the earliest sign of increased muscle tone

- increased muscle tone in the lower limb can be tested by gently rolling the leg from side-to-side with your hand under the knee, and when the leg is rolling freely, quickly flick the knee up in the air => the normal leg will passively flex at the knee, while the spastic leg will remain stiff and jerk up in the air

- acute pathology affecting the corticospinal tract may produce weakness, flaccidity, hyporeflexia and an absent Babinski response mimicing a LMN lesion => it may not be easy to differentiate between a cauda equina lesion and a lower spinal cord lesion if the pathology is acute eg. spinal infarction, extradural hematoma or spinal hemorrhage (hematomyelia), acute lumbar disc herniation, acute spinal trauma http://www.homestead.com/emguidemaps/files/spinalcord.html (4 of 14)8/20/2004 5:15:00 PM spinalcord

- the acute hyporeflexia associated with spinal shock may take weeks to recover, and overt clinical evidence of UMN pathology (hyperreflexia and spasticity) may be delayed

- a clue that any muscle weakness is due to an UMN lesion is that UMN weakness mainly affects generalised movements rather than particular muscles, and UMN weakness mainly affects the extensor groups of the arms (shoulder abductors, elbow extensors, wrist extensors) and flexor groups of the legs (hip flexors, knee flexors and foot dorsiflexors)

(* the anti-gravity muscles are relatively preserved - biceps of the upper limbs and quadriceps of the lower limbs)

- myelopathies affecting the cervical anterior horn cells (amyotrophic lateral sclerosis, syringomyelia, intramedullary tumors) => weakness + muscle atrophy + fasiculations of the upper limbs (especially intrinsic hand muscles) + hyperreflexia of the lower limbs (due to corticospinal tract involvement)

Clinical clues suggesting motor deficits secondary to chronic spinal cord disease

● spasticity precedes weakness ● spasticity is associated with increased muscle tone and hyperreflexia and clonus and a positive Babinski (extensor plantar response) ● weakness mainly involves generalized movements rather than a particular muscle group ● weakness mainly affects the extensor groups of the arms and flexor groups of the legs => the patient appears "stiff" with flexed arms and extended legs ● loss of independent fine finger motor movements => clumsiness of finger movements

Radicular symptoms

- produced at the level of the lesion if the lesion affects the nerve roots

- they are of precise localising value if present

- may produce unilateral or bilateral symptoms

- sensory symptoms may vary widely - from severe knife-like pains, icy-cold bandage-wrap sensations to vague warm glowing sensations - and they usually extend from the back along a dermatomal pattern

- bilateral T3/T4 dermatomal pain may mimic a heart attack or heartburn

Anterior cord syndrome

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● characterised by a loss of motor function and pain-temperature sensation below the level of the lesion + preserved posterior column function (position sense and vibration sense) ● typically seen following hyperflexion injuries with impingement of bone or herniated disc tissue directly on the anterior spinal cord, or due to mechanical compression of the anterior spinal artery and secondary infarction of the anterior spinal cord, or rarely due to aortic dissection interrupting the blood supply to the anterior spinal arteries

Central cord syndrome

● most commonly associated with hyperextension injuries in elderly patients with cervical spondylosis and a narrow cervical canal => buckling of the ligamentum flavum => pincer-mechanism cord compression against vertebral body osteophytes in a narrow cervical canal => greatest compressive effects on the central mass of the cord substance => bilateral arm weakness >> lower limb weakness with paresis more dense distally than proximally +/- variable sensory impairment (pain and temperature sensory loss >> propioceptive sensory loss) and bladder dysfunction (* mnemonic MUD = motor > sensory, upper > lower, and distal > proximal) ● the degree and location of the neurological deficits depends on the exact location and size of the lesion ● bilateral "burning hands" paresthesias may be an early symptom and may precede any neurological signs, or may occur in isolation without any neurological deficits ● this syndrome may also be chronic and slowly progressive in its time-course - seen in chronic cervical spondylosis compressing the spinal cord, and in syringomyelia, and in tumors of the central spinal cord (see the appendix for a graphic presentation of evolution of chronic central http://www.homestead.com/emguidemaps/files/spinalcord.html (6 of 14)8/20/2004 5:15:00 PM spinalcord cord syndrome)

Posterior cord syndrome

● characterized by proprioceptive sensory loss + preservation of pain and temperature sensory function + preservation of motor function ● usually due to posterior spinal artery occlusion, chronic atherosclerosis and impaired collateral circulation, tumors or discs compressing the posterior spinal cord, or vitamin B12 deficiency

Brown-Sequard syndrome

● lateral cord syndrome due to a lesion involving half of the spinal cord ● ipsilateral loss of motor function and proprioceptive sensory function + contralateral loss of pain-temperature sensation ● most commonly due to traumatic hemisection of the spinal cord (eg. stabbing knife thrust); rarely due to radiation injury or air embolism associated with scuba diving; can also occur secondary to spinal tumors or other local pathology compressing the lateral spinal cord ● partial Brown-Sequard syndromes are more common => varying degrees of paresis and analgesia

Inferior cord syndrome (conus medullaris) syndrome

● involvement of the terminal spinal cord ● usually of rapid onset ● more severe back pain, less severe radicular symptoms ● symmetrical defects ● weakness sacral ● saddle distribution sensory loss +/- sensory dissociation ● tendon reflex loss - ankle > knee ● early consistent impotence +/- bladder involvement ● subacute lesions may produce UMN signs - hyperreflexia of ankle jerks, increased anal tone and spastic bladder ● see emedicine.com's cauda equina syndrome chapter for further details

Cauda equina syndrome

● slow progressive loss; often asymmetric or unilateral ● often due to chronic disc herniation +/- spinal stenosis ● may be due to spinal tumors ● less severe back pain, may produce severe radicular symptoms ● sensory loss affects all sensory modalities - lumbar > sacral ● sensory loss may affect penis/clitoris and pubic area, and be asymmetrical ● sensory loss may follow a specific dermatomal pattern ● muscle weakness - lumbar > sacral ● muscle weakness mainly affects glutei, hamstrings, gastrocnemius and soleus muscles ● muscle atrophy and fasiculations common http://www.homestead.com/emguidemaps/files/spinalcord.html (7 of 14)8/20/2004 5:15:00 PM spinalcord

● tendon reflex loss - knee > ankle ● bladder involvement late (flaccid bladder) ● see emedicine.com's cauda equina syndrome chapter for further details

Syringomyelia

● the result of central cord cavitation affecting a few segments, and usually involving the cervical spinal cord ● frequently found in Arnold-Chiari malformations affecting the upper cervical cord and medulla ● mainly affects the crossing fibres of the spinothalamic tract as they decussate in the ventral white commissure => bilateral pain-temperature sensory loss over a few segments eg. only affecting the neck and upper shoulders in a cape-like distribution (or only affecting the upper limbs) with normal sensation above and below the affected dermatomes ● does not affect the spinothalamic tracts in the early stages => no initial lower trunk or lower limb pain-temperature sensory loss ● does not usually affect the dorsal columns => normal position sense ("dissociative" sensory loss) ● may rarely affect the lower motor neurons to the upper limbs early in the disease course, and may eventually affect the corticospinal tracts ● may affect the spinal extension of the trigeminal nucleus => face hypoesthesia in a characteristic balaclava helmut distribution

Clinical clues and clinical spinal cord syndromes

- it is important to keep some general principles in mind when attempting to diagnose a spinal cord syndrome

Patients often have sensory symptoms in the absence of detectable sensory deficits, whereas detectable motor signs may be found in the absence of motor symptoms

Acute motor signs may consist of weakness and hyporeflexia (due to spinal shock), while chronic motor signs are more likely to consist of spasticity and hyperreflexia

Because motor weakness due to corticospinal tract involvement affects generalised movements, it may not be possible to definitively determine a spinal cord level based on the motor examination => a sensory examination showing a discrete sensory dermatomal deficit level may better determine that a sensorimotor deficit is due to spinal cord disease (rather than due to a radiculopathy or a peripheral neuropathy)

The presence of back pain + spinal percussion tenderness in the presence of a new neurological deficit strongly suggests spinal cord disease

- local pain over the spine developing over minutes-hours +/- neuro deficits => spinal hemorrhage, spinal infarction, vertebral fracture, acute disc herniation

- local pain over the spine developing over hours-days +/- neuro deficits => epidural abscess or epidural hematoma or transverse myelitis

- local pain over the spine developing over months +/- neuro deficits => spondylosis or infection or tumors

- radicular pain due to spinal disease is rarely seen without local spinal pain and radicular pain does not radiate to the terminal sensory distribution of http://www.homestead.com/emguidemaps/files/spinalcord.html (8 of 14)8/20/2004 5:15:00 PM spinalcord the involved nerve (although associated paresthesias may extend to the terminal nerve ends)

- Lhermitte's sign = Electric-shock sensations lasting seconds and extending from the neck down the back +/- radiation to the limbs, and which usually occur when the neck is flexed - is most commonly seen in multiple sclerosis, but is also seen in other lesions affecting the posterior cervical spinal cord eg. cervical spondylosis compressing the posterior spinal cord

- hyporeflexia could be due to nerve root pathology (eg cauda equina syndrome), but is also seen temporarily in acute spinal cord pathology (spinal shock - trauma, infarction, hemorrhage, disc herniation or transverse myelitis)

- hyperreflexia is eventually seen in all spinal cord syndromes and finding a reflex level is of localising importance

● hyperreflexia of the lower limbs + normoreflexia of the upper limbs => lesion of the thoracic or lumbar cord ● hyperreflexia of the lower limbs and finger flexors + normal biceps reflex => lower cervical cord lesion ● hyperreflexia of the lower limbs + hyporeflexia of the upper limbs => cervical spondylitic myelopathy + radiculopathy, or cervical central cord pathology involving the LMNs to the upper limbs ● hyperreflexia of the upper and lower limbs + normal jaw jerk => upper cervical cord lesion

- an extensor plantar response (Babinski sign present) is often seen in early spinal cord disease, but it is occasionally absent even in advanced disease

- bladder dysfunction is not an early symptom of spinal cord disease; lesions of the cauda equina or acute/subacute myelopathies (spinal shock) => flaccid bladder with urinary retention and overflow incontinence; while more slowly progressive myelopathies => spastic bladder with urgency, frequency and incontinence

The combination of spasticity + poor coordination + incontinence => spinal cord disease until proved otherwise (also consider frontal lobe disease and normal pressure hydrocephalus)

- early cervical central cord syndrome will be missed if a careful pain-temperature sensory examination of the neck, shoulder area, upper trunk and upper extremities is not performed - because an isolated band of pain-temperature hypoesthesia may be the sole abnormal finding in early disease

An acute myelopathy can be due to a transverse myelitis, but this is a diagnosis of exclusion - first exclude acute compressive myelopathies by immediate neuroimaging

Differential diagnosis of spinal cord syndromes

Local pain + quadriplegia/paraplegia + non-selective sensory loss + loss of bladder function

● acute (minutes) => spinal cord infarction (often spares the dorsal columns), spinal cord trauma, spinal hemorrhage, acute disc herniation ● subacute (hours, days, weeks) => transverse myelitis, spinal epidural abscess, spinal epidural tumor

Chronic spastic quadriplegia/paraplegia + spastic gait ataxia (evolving over months-years) http://www.homestead.com/emguidemaps/files/spinalcord.html (9 of 14)8/20/2004 5:15:00 PM spinalcord

● disorders with no sensory abnormalities => amyotrophic lateral sclerosis, myelopathy of cervical spondylosis, familial spastic paraplegia ● disorders with loss of proprioception => arachnoiditis, spinal multiple sclerosis, myelopathy of cervical spondylosis, arteriovenous malformation, subacute combined degeneration of the spinal cord, AIDS myelopathy, spinocerebellar degeneration, spinal tumors, tabes dorsalis ● disorders with loss of pain-temperature sensation => spinal tumors, myelopathy of cervical spondylosis, radiation myelopathy

Chronic atrophic paralysis of the hands (evolving over months-years)

● disorders with segmental sensory loss involving pain-temperature only or all sensory modalities => syringomyelia, spinal tumors, spinal cord injury ● disorders without sensory loss => amyotrophic lateral sclerosis, cervical spondylosis, extrinsic tumors of the upper cervical cord

Chronic paraplegia + low back pain + areflexia + loss of bladder function (Cauda equina syndrome)

● herniated disc, spinal stenosis, tumors of the cauda equina, arachnoiditis

Rapidly evolving areflexic quadriparesis/paraparesis in the absence of trauma or spinal compression

● acute transverse myelitis (back pain + sensory deficit/level + normal reflexes above the lesion + bladder dysfunction)

Differential diagnosis

● Guillane-Barre syndrome => rapidly evolving areflexic quadriparesis/paraparesis (no back pain + no sensory deficits + diffuse areflexia + normal bladder dysfunction +/- cranial nerve dysfunction) ● bilateral anterior cerebral artery occlusion => acute paraplegia + urinary incontinence + hyperreflexia +/- gait apraxia +/- dementia +/- sensory loss (sensory loss in cortical infarction only involves position sense and spares pain-temperature = exact opposite of spinal infarction) ● normal pressure hydrocephalus => gait ataxia +/- bilateral limb weakness + urinary incontinence + no spasticity or sensory deficits

For further information on many diseases causing spinal cord syndromes, consult this excellent online website

http://www.neuro.wustl.edu/neuromuscular/spinal.html

Appendix

Motor testing

- there is no "pure" single nerve testing of the upper and lower limbs http://www.homestead.com/emguidemaps/files/spinalcord.html (10 of 14)8/20/2004 5:15:00 PM spinalcord - some easy-to-remember combinations include:-

● shoulder abduction - C5 ● elbow flexion - C 5,6 ● elbow extension - C7 ● wrist and finger extension - C7 ● finger flexion - C8 ● finger abduction - C8, T1 ● thumb adduction and opponens - T1 ● hip flexion - L 2, 3, 4 ● knee extension - L 3, 4 ● foot dorsiflexion - L 4, 5 ● 2nd - 5th toe dorsiflexion - L 5 ● 1st toe dorsiflexion - L 5 or S1 ● foot plantar flexion - S1 ● squeezing buttocks together (gluteus maximus) - S1 ● anal sphincter "tightening" - S2, 3, 4

- the biceps reflex is C5/6, triceps reflex is C7/8, knee reflex is L3/4 and the ankle reflex is S1

(* although many textbooks/journal articles suggest that first toe dorsiflexion innervation is primarily from L5, other textbooks/journal articles suggest S1 as the major innervation=> because of this discrepancy in opinions, it is recommended that you use foot and small toe(s) dorsiflexion for L5 testing and plantar flexion of the foot for S1 testing)

Grading of motor strength

● 5+ = Normal ● 4+ = Slightly less than full power against resistance ● 4 = Able to overcome moderate resistance ● 4 - = Able to overcome mild resistance ● 3 = Able to accomplish full ROM against gravity ● 2 = Able to accomplish full ROM with gravity eliminated ● 1 = Only trace muscle contraction, may only be palpable ● 0 = Flaccid

Sensory dermatomes

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Somatotopic anatomy of the spinal cord

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Summary of the clinical features of some spinal cord syndromes

Pain Percussion Acute Chronic Fever Flaccidity Spasticity Reflexes Sensory tenderness progression progression deficit Epidural +++ ++ +++ + - +++ - + ++ hematoma Epidural ++++ +++ ++ ++ +++ +++ (acute) ++ + ++ abscess (chronic) Primary + + - +++ - + +++ +++ + neoplasm Secondary +++ +++ + ++ - ++ ++ + + metastasis Trauma +++ +++ +++ - - +++ - - ++ Cervical +/- +/- - +++ - - +++ +++ + spondylosis Transverse +/- - +++ - +/- ++ late +/- +++ myelitis

(* see the low back pain guidemap for more information on the diagnostic workup of some spinal cord syndromes)

Evolution of chronic central cord syndrome http://www.homestead.com/emguidemaps/files/spinalcord.html (13 of 14)8/20/2004 5:15:00 PM spinalcord

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemap - Nystagmus

Click on any of the headings or subheadings to rapidly navigate to the relevant section of the guidemap

Introduction

Definitions and general principles

Diagnostic approach to pathologic nystagmus

● binocular conjugate nystagmus

● peripheral vestibular nystagmus

● central vestibular nystagmus

● periodic alternating nystagmus

● upbeat nystagmus

● downbeat nystagmus

● gaze-evoked nystagmus

● pendular nystagmus

● binocular dysconjugate nystagmus

● monocular or asymmetric binocular nystagmus

Eye movement disorders that mimic nystagmus

Introduction

- this guidemap is a companion guidemap to the ataxia, incoordination and dysequilibrium guidemap and the vertigo guidemap, and this guidemap offers a reader much more detailed information on nystagmus

- this guidemap serves two purposes:-

● gives a reader a clearer understanding of what causes nystagmus, and how nystagmus is classified ● serves as a "mini-reference bible" of many different types of acquired nystagmus, so that readers can use the hyperlink mechanism to selectively read through

http://www.homestead.com/emguidemaps/files/nystagmus.html (1 of 23)8/20/2004 5:15:04 PM nystagmus individual sections, as needed

(* note that this guidemap is very selective in its presentation of information on nystagmus, and that it does not deal with latent nystagmus or congenital nystagmus => this guidemap is primarily focused on providing basic problem-solving information on acquired nystagmus in adult patients and older children)

Definitions and general principles

What is nystagmus?

Nystagmus is a rhythmic oscillation of the eyes, which may be physiologic or pathologic

The ryhthmic oscillation may be symmetrical (speed of oscillation to one side is the same as the speed of oscillation to the other side) - labelled pendular nystagmus

Alternatively, the rhythmic oscillation of the eyes may be asymmetrical (speed of oscillation to one side is slower than the speed of oscillation to the other side) - labelled jerk nystagmus

The direction of a jerk nystagmus is defined by the direction of the rapid oscillatory phase

In jerk nystagmus, the slow phase is the first (pathologic) phase, and the rapid phase is the second (corrective) phase. Therefore, if the rhythmically oscillating eyes drift slowly to the left and then jerk back rapidly to the right => the jerk nystagmus is classified as a right horizontal jerk nystagmus

Nystagmus may occur with the eyes in primary forward gaze, and/or only in eccentric gaze (to the sides, up-or-down, or obliquely)

If the jerk nystagmus occurs spontaneously in primary forward gaze, then it is classified according to the direction of the nystagmus - and it may be classified as horizontal, vertical, torsional, oblique or mixed

Vertical nystagmus can be sub-classified, according to whether the rapid phase is upward (upbeat nystagmus) or downward (downbeat nystagmus)

Upbeat jerk nystagmus refers to vertical nystagmus where the primary slow drift is downwards, and the rapid corrective phase is upwards

http://www.homestead.com/emguidemaps/files/nystagmus.html (2 of 23)8/20/2004 5:15:04 PM nystagmus Downbeat jerk nystagmus refers to vertical nystagmus where the primary slow drift is upwards, and the rapid corrective phase is downwards

Although vertical nystagmus is defined according to the direction of the fast phase, the amplitude of the slow phase and rapid corrective phases can vary according to the direction of gaze. For example, downbeat nystagmus, which is present in primary gaze, can be worse on downward or lateral gaze (eccentric eye position). Sometimes, downbeat nystagmus may not be present in forward gaze and only be present on downward gaze. In that situation, it is still defined as downbeat nystagmus - because of the downward direction of the rapid (corrective) phase of the nystagmus. However, if a jerk nystagmus only occurs in an eccentric eye position, and not the primary eye position, it is called a gaze-evoked nystagmus. Therefore, a downbeat nystagmus that only occurs on downward gaze, is classified as a gaze-evoked downbeat nystagmus

If jerk nystagmus only occurs with certain positions of the head (rather than varying positions of gaze) it is classified as a positional nystagmus.

(* see the vertigo guidemap for further information on how to differentiate peripheral positional nystagmus from central positional nystagmus)

What causes physiologic nystagmus?

Normally the eyes remain in the position of primary gaze, even when a person is not deliberatedly focusing on any visual target directly ahead, because of balanced input from the left-and-right vestibular systems, which are finely tuned to respond to any movement of the head relative to the body.

If a person turns his head to the side without making any deliberate attempt to fixate on any visual target, the eyes will remain centered in the neutral position of primary gaze as a result of the vestibulo-ocular reflex (a reflex mediated via the vestibular system), which ensures that the eyes respond promptly to any movement of the head relative to the body in order to keep the eyes centered in the socket. If that person spins around in a circle (like a ballerina), theoretically the eyes should follow the head at the same speed, so that an observer will notice that eyes remain centered in the head as the person swivels around. However, if that person spins too fast, vertigo will ensue if the movement of the eyes cannnot keep up with the speed of rotational movement of the head (due to the slow latency of response of the vestibulo-ocular reflex) => the vertigo is due to the disparity in eye movements relative to head movements. Physiologic nystagmus will occur if the conscious brain of the spinning person deliberatedly interferes with the smooth movement of the eyes during rotation of the body, by deliberately fixating on different visual targets during the spin. If the eyes fixate on a vusual target during a rotational spin, the eyes will obviously be lagging behind the movement of the body as it continues to rotate, and it

http://www.homestead.com/emguidemaps/files/nystagmus.html (3 of 23)8/20/2004 5:15:04 PM nystagmus would appear to an observer that the eyes are moving smoothly in the opposite direction of the body. Ballerinas use this technique to prevent getting dizzy during rapid pirouettes. When the ballerina reaches a certain point in her rotational spin (when the eyes are displaced to the near-extreme limits of its excursion in the socket), she re-fixates her eyes on another visual target, and the voluntary saccade causes a rapid eye movement to the intended re-fixation position. In other words, the pirouetting ballerina has self-induced physiologic nystagmus - a rhythmic oscillation of the eyes, with alternating fast phases and slow phases, and the fast phase occurs a result of the conscious brain's attempt to re- fixate a visual target.

What causes pathologic nystagmus?

- pathologic nystagmus occurs when the eyes drift slowly from their intended position (primary forward gaze or eccentric gaze) as a result of an abnormality of one of the slow eye movement controlling systems or the neuro-regulatory "gaze-holding" system controlling eccentric gaze. In most cases, the drift is corrected by a rapid eye movement - an automatic phenomenon of a conscious brain - that brings the eye back to its intended position

Diagnostic approach to pathologic nystagmus

What are the symptoms and signs of nystagmus?

- nystagmus is rarely the main clinical sign, and many patients with pathologic nystagmus present with a symptom complex that varies with the underlying disease (eg. acute peripheral vestibular syndrome, or acute cerebellar syndrome) and the other symptoms dominate the clinical picture

- when nystagmus is the main clinical sign, the patient may complain of blurred vision or oscillopsia

- oscillopsia is an illusory sensation of enviromental movement, and the sensation can vary from a to-and-fro oscillation of the enviroment to various degrees of tilting of the enviroment

- nystagmus can be subtle, and use of a slit lamp or ophthalmoscope may help a physician detect a subtle torsional nystagmoid movement (remember that the direction of nystagmus is reversed when using an ophthalmoscope)

- when observing a patient with nystagmus, it is worthwhile making the following series

http://www.homestead.com/emguidemaps/files/nystagmus.html (4 of 23)8/20/2004 5:15:04 PM nystagmus of observations, because the correct classification of the nystagmus significantly narrows the number of differential diagnoses causing the nystagmus

● does the nystagmus involve both eyes? (binocular rather than monocular) ● does the nystagmus involve both eyes symmetrically? (binocular symmetric rather than dissociated) ● does the nystagmus cause the eyes to move in the same direction, or opposite directions? (conjugate or dysconjugate) ● does the nystagmus occur spontaneously with the eyes in the primary position? (spontaneous) ● does the nystagmus only occur when gaze is directed to an eccentric gaze position (gaze-evoked nystagmus) ● does the nystagmus occur in all cardinal positions of eccentric gaze, or is there a null point where nystagmus does not occur, and is there varying amplitude of the nystagmus in different positions of gaze? ● is the first eye movement phase slower than the second eye movement phase? (jerk nystagmus) ● are the first and second movement phases equal in amplitude? (pendular nystagmus)

- this guidemap delineates a particular system of classifying nystagmus, based on the above observations

Binocular symmetric oscillations of the conjugate type

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- binocular symmetric nystagmus may include patients with symmetric eye movements in the same direction (conjugate nystagmus), or opposite directions (dysconjugate nystagmus)

- binocular conjugate nystagmus is divided into two types => jerk nystagmus and pendular nystagmus

- spontaneous jerk nystagmus is divided into two types => primary position jerk nystagmus and eccentric position jerk nystagmus (gaze-evoked jerk nystagmus)

- spontaneous primary position jerk nystagmus is divided into two groups => vertigo present, vertigo absent

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Peripheral vestibular nystagmus

What causes peripheral vestibular nystagmus?

Normally the left and right vestibular organs are constantly responding to movements of the head in space, and there is continuous input into the reflex vestibulo-ocular system. Pathologic nystagmus occurs when there is an imbalance in the input from the different sides of the vestibular system. An example would be unilateral disease of one vestibular organ causing a loss of input signal from the one side. Then the only remaining signal inputting the reflex vestibulo-ocular system would be from the other vestibular organ, which drives the eyes slowly and tonically in the direction of the opposite side (towards the affected ear). The conscious brain cannot tolerate drift of the eyes from the primary forward gaze position and it instructs the eyes to make a rapid corrective saccade back to the central position. The direction of the fast corrective movement is arbitrarily defined as the direction of nystagmus, although the pathological eye movement is really the initial slow movement. Therefore, in unilateral vestibular disease involving the left ear, the eyes will drift slowly towards the left ear (because of the unopposed tonic input from the normal right vestibular organ) and then rapidly jerk back towards the opposite side (the side of the normal ear). Because the pathological imbalance in vestibular function is continuously present in the acute phase, there is a continuous tonic tendency for the eyes to slowly drift conjugatedly towards the affected side, and then jerk back to the normal side - and this produces a constantly recurring jerk nystagmus

(* note that a conscious brain is needed to produce the rapid corrective eye movement, and that peripheral nystagmus disappears during sleep).

Can peripheral vestibular nystagmus occur in the presence of bilateral vestibular disease?

If the vestibular disease affected both vestibular organs to the same degree, then the lack http://www.homestead.com/emguidemaps/files/nystagmus.html (7 of 23)8/20/2004 5:15:04 PM nystagmus of tonic input signal from the two sides would cancel-out, and there would no tendency for the eyes to drift to one side, and there would no physiological need for a corrective rapid phase => nystagmus would not occur. Peripheral nystagmus only occurs if there is an imbalance in tonic signal from the opposite sides, because one side is affected more than the other side. Therefore, nystagmus only occurs if a particular vestibular disease affects both vestibular organs (eg. vestibular neuronitis), but there is a significant difference in the degree of disease-involvement between the left and right vestibular organs.

Why is peripheral vestibular nystagmus always horizontal or horizonto-torsional, and never vertical?

Each vestibular organ consists of three semicircular canals - anterior, posterior and horizontal. The right anterior canal works in tandem with the left posterior canal to detect any movement of the head in one plane, while the right posterior canal works together with the left anterior canal to detect movement in another plane at right angles to the first plane. The vestibular system uses these pairs of canals in a "push-pull" reciprocal manner, so that any angular movement of the head will maximally activate one semicircular canal and maximally inhibit its counterpart. Therefore, the tonic signals from the left anterior canal balances the tonic signals from the posterior canal of the opposite side (and vica versa), while the horizontal canal tonic signals cancel each other out.

If a disease caused loss of right anterior canal function, there would be a nystagmus that is a mix of upbeat and counterclockwise torsional fast phases; and if there was a loss of right posterior canal function, there would be a nystagmus that is a mix of downbeat and counterclockwise torsional fast phases. If all three right sided canals were affected by an unilateral vestibular disease, the upbeat and down beat componenets would cancel-out, but the counter-clockwise torsional effects would add together with the left beating nystagmus (due to disease of the right horizontal canal) to create a mixed torsional-horizontal nystagmus.

Vertical nystagmus doesn't occur in peripheral vestibular disease because the pathology would have to differentially affect the posterior canals of both sides, summating the resulting loss of upward slow drifts and cancelling the opposing slow torsional drifts - which is very unlikely.

Pure torsional nystagmus could theoretically occur if unilateral vestibular disease affected both the anterior and posterior canal on one side, sparing the horizontal canal. However, this is very unlikely to occur because the nerve and blood supply of the horizontal + anterior canals are separate from that of the posterior canal. So, even if the unilateral vestibular disease was partial, it would not affect only the anterior canal without affecting the horizontal canal. In fact, partial vestibular neuronitis either causes a dysfunction of the

http://www.homestead.com/emguidemaps/files/nystagmus.html (8 of 23)8/20/2004 5:15:04 PM nystagmus one horizontal canal, or both the horizontal and anterior canal of one side.

What are the typical characteristics of peripheral vestibular nystagmus?

● mixed horizontal-torsional trajectory, or purely horizontal trajectory ● vertical or purely torsional nystagmus never occurs ● linear, constant velocity, slow phases ● nystagmus is always in the same direction even when present in different directions of gaze ● nystagmus increased when the eyes are turned in the direction of the fast phase (Alexander's law) ● nystagmus suppressed by visual fixation; amplitude of nystagmus increased when fixation is removed ● horizontal component decreased when the patient lies down with the intact ear down; and increased when the affected ear is down ● nystagmus may be increased by changes in head position, vigorous head-shaking, hyperventilation or Valsalva maneuver ● bedside caloric stimulation shows unilateral impaired ability to modulate spontaneous nystagmus ● saccades and smoooth eye pursuits are relatively preserved ● nystagmus remits with time, and is usually only present during the acute phase ● vertigo and nausea/vomiting may be prominent in acute vestibular syndrome ● any tendency to fall, or past-point, is always in the direction of the slow phase of the nystagmus ● hearing loss and tinnitus may be present ● neurological symptoms are absent

- some physicians grade peripheral vestibular nystagmus

● grade 1 = nystagmus only present on gaze in the direction of the fast phase (away from the lesion) ● grade 2 = nystagmus also present in primary gaze ● grade 3 = nystagmus also present in the direction of the slow phase

Central vestibular nystagmus

- although vertigo is also present in central vestibular syndrome, it is not as prominent a complaint (compared to acute peripheral vestibular syndrome)

- posterior fossa neurological symptoms/signs are common

What are the typical characteristics of central vestibular nystagmus?

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● nystagmus may be horizontal, vertical, purely torsional, or mixed ● nystagmus may be bi-directional, and change direction in different directions of gaze ● nystagmus is unaffected by visual fixation ● nystagmus is constant and does not wane with time ● impaired saccades and impaired smooth eye pursuit movements are commonly present ● brainstem and cerebellar signs are commonly present ● any associated vertigo and nausea/vomiting is mild ● any tendency to fall is often multi-directional, and not unidirectional ● hearing loss is rarely present

- a common cause of central nystagmus is lateral medullary syndrome (Wallenberg's syndrome) due to a vertebral artery occlusion or posterior inferior cerebral artery stroke

- signs of Wallenberg's syndrome may include:-

● ipsilateral loss of pain and temperature sensation of the face ● contralateral loss of pain and temperature sensation of the trunk and limbs ● ipsilateral Horner's syndrome ● dysarthria and dysphagia ● ataxia of the ipsilateral limbs ● distinctive type of central nystagmus - with the eyes open, a horizontal jerk nystagmus beats away from the side of the lesion => with the eyes closed or fixation disrupted, the nystagmus either stops or reverses direction ● illusory sensation of the enviroment tilting 90 - 180 degrees ● ocular lateropulsion (eyes tend to deviate obliquely towards the side of the lesion during vertical saccades) ● saccades are hypometric and smooth eye pursuit is impaired away from the side of the lesion ● saccades are hypermetric and smooth eye pursuit is normal toward the side of the lesion

Periodic alternating nystagmus

- PAN is the only binocular conjugate nystagmus that occurs spontaneously in primary gaze (without any accompanying vertigo) that is horizontal in direction

- PAN is a jerk nystagmus with a cyclically moving or wandering null point, and the nystagmus may disappear for 10 seconds to be followed by ascending and decending intensity unilateral jerk nystagmus lasting about 90 seconds, followed by a 10 second null

http://www.homestead.com/emguidemaps/files/nystagmus.html (10 of 23)8/20/2004 5:15:04 PM nystagmus period of no/minimal nystagmus in a downbeating direction, and then a repeat pattern of crescendo horizontal nystagmus in the opposite direction for 90 seconds

- the patient may complain of episodic visual blurring or oscillopsia

- usually due to a lesion in the cervicomedullary area affecting the vestibular nucleus (eg, Arnold-Chiari malformation) => the patient requires diagnostic MRI neuro-imaging of the posterior fossa

- other causes of PAN include degenerative spincocerebellar disease, multiple sclerosis, Creutzfeldt-Jacob disease, ataxia-telangiectasia, brainstem infarcts, cerebellar mass lesions, neurosyphilis, hepatic encephalopathy, trauma, anticonvulsant drugs, or following visual loss

Upbeat nystagmus

- the nystagmus has an upbeating rapid phase in the primary position, and is often worse with upgaze

- convergence may enhance, suppress or reverse the direction of the nystagmus

- impaired smooth pursuit always occurs

- associated gaze-evoked or rebound nystagmus may also occur

- internuclear ophthalmoplegia and skew deviations are less common

- does not have much localizing value and is mainly seen in lesions of the medulla, cerebellar vermis, and midline brainstem

- when downgaze increases the nystagmus, the lesion is usually in the medulla

- causes of upbeat nystagmus include:-

● cerebellar degeneration ● brainstem or cerebellar stroke ● brainstem or cerebellar tumor ● demyelination ● viral encephalitis or meningitis ● tuberculoma ● Behcet's disease

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● sarcoidosis ● anticonvulsants (phenytoin, carbamazepine) ● organophosphate poisoning (anticholinesterase insecticides)

Downbeat nystagmus

- the nystagmus has a downbeating rapid phase in the primary position

- the vertical nystagmus is often worse with downgaze or lateral gaze just below the horizontal, and less severe in upgaze

- there may be a mild horizontal component, so that the nystagmus can be oblique on lateral gaze

- the patient may present with blurred vision, oscillopsia or gait imbalance

- oscillopsia is often present during reading, because the nystagmus is often worse on downward gaze

- the nystagmus may be intermittent or constant

- a compressive problem (Arnold-Chiari malformation, hydrocephalus or osteophytes compressing the vertebral artery) should be suspected if oscillopsia is provoked by neck extension or rotation

- there may be diplopia due to associated skew deviations of the eyes

- other eye movement abnormalities are commonly associated with downbeat nystagmus, especially poor downward smooth pursuit

- the "floccular syndrome" consists of downbeat nystagmus, gaze-evoked nystagmus and rebound nystagmus, and abnormal horizontal smooth pursuit; and is due to a cerebellar flocculus lesion

- the most common pathology causing downbeat nystagmus are cervico-medullary junctional area lesions

- causes of downbeat nystagmus include:-

● cervico-medullary junction anomalies (eg. Arnold-Chiari malformation) ● lesions of the cerebellar flocculus or its projection

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● hereditary cerebellar degeneration ● paraneoplastic cerebellar degeneration ● multiple sclerosis affecting the brainstem or cerebellum ● vertebrobasilar area infarctions ● lithium and anticonvulsants (phenytoin, carbamazepine, felbamate) ● hypomagnesemia ● alcohol (acute and chronic effect) ● toluene abuse ● vitamin B12 deficiency ● Wernicke's encephalopathy ● viral encephalitis (herpes simplex. HIV) ● posterior fossa tumors ● hydrocephalus ● idiopathic

Gaze-evoked (eccentric position) nystagmus

- this form of binocular conjugate nystagmus is provoked by moving the eyes into an eccentric gaze position, and is not present at rest in the primary forward gaze position

- gaze-evoked nystagmus is usually due to a defect in the central neural integrators controlling gaze-holding, and infrequently due to weakness of the extraocular muscles or their innervation (gaze-paretic nystagmus)

(* the central neural intergrators consist of neural connections between the vestibulocerebellum, the medulla and the interstitial nuclei of Cajal in the midbrain)

- diseases that cause central gaze-evoked nysgamus often also produce defects in visual fixation and smooth pursuit eye movements

- common types of gaze-evoked nystagmus include:-

● physiologic nystagmus ● gaze-paretic nystagmus ● drug-induced nystagmus ● horizontal rotatory nystagmus ● rebound nystagmus ● downbeat nystagmus

Physiologic nystagmus

- also called end-point nystagmus, and occurs when a person looks laterally beyond 40 http://www.homestead.com/emguidemaps/files/nystagmus.html (13 of 23)8/20/2004 5:15:04 PM nystagmus degrees for an extended period

- the nystagmus is a low-amplitude horizontal nystagmus with the rapid phase directed laterally

- the initial slow phase is due to the intrinsic elastic pull of the stretched eye muscles/ tendons which are constantly pulling the eyes centripetally back towards the neutral position, and the rapid phase is a corrective movement back towards the eccentric position of desired gaze (secondary to input from the brain's central "gaze-holding" neural integrator)

- usually does not occur until the eyes have been held in an eccentric position for longer than a few seconds (often only after > 30 seconds)

- fatigue nystagmus may become increasingly torsional with prolonged deviation effort, and it may be greater in the adducting eye

- gaze-evoked nystagmus is not physiological if:- i) there is asymmetry of nystagmus in two directions of gaze, ii) the amplitude of the nystagmus exceeds 4 degrees, iii) the slow phase is not linear within a gaze angle of 40 degrees (slow phase has an exponentially decreasing velocity), or iv) if there are any associated eye movement defects eg. impaired smooth eye pursuit movements

Gaze-paretic nystagmus

- represents a failure to maintain an eccentric eye position due to relative weakness of certain eye muscles

- occurs during the recovery phase of central gaze palsy or other gaze pareses (eg. myasthenia gravis, or Miller-Fisher variant of Guillane Barre syndrome) when recovery is sufficient to make a conjugate movement, but recovery is not sufficient to maintain an eccentric gaze position

- following an initially adequate saccadic gaze movement, the eyes drift back towards the primary eye position, and a rapid corrective saccade is initiated taking the eyes back to the intended eccentric position of gaze

- the jerk nystagmus is often bi-directional in central causes of gaze-evoked nystagmus, because the rapid phase is always in the direction of gaze (and the slow phase is always the initial centripetal drift of the eyes, which is usually due to an insufficient step-signal from the central neural integrator responsible for maintaining gaze-holding of the eyes in an eccentric gaze position) http://www.homestead.com/emguidemaps/files/nystagmus.html (14 of 23)8/20/2004 5:15:04 PM nystagmus

- if the amplitude of the nystagmus is equally great when looking eccentrically to the left and right, it suggests a central gaze palsy and is of no localizing value; if the gaze-evoked nystagmus is asymmetric, then it suggests a peripheral gaze palsy, or a central gaze palsy due to unilateral brainstem or cerebellar disease and the amplitude of the nystagmus is greatest when looking towards the side of the lesion

- gaze-evoked upbeat vertical nystagmus on upgaze almost always co-exists with symmetrical horizontal gaze-evoked nystagmus, and it has no CNS localizing value; gaze- evoked nystagmus on downgaze is very uncommon

Drug-induced nystagmus

- the jerk nystagmus is usually horizontal or horizontal-torsional, but can be upbeat vertical on upgaze

- due to anticonvulsant drugs, which are the most common cause of gaze-evoked nystagmus

Horizontal rotatory nystagmus

- a common non-specific finding in brainstem disease

- Brun's nystagmus is a combination of a gaze-evoked central nystagmus (from compression of the pons) and horizontal-rotatory peripheral nystagmus (from damage to the vestibular verve), secondary to lesions in the cerebellopontine angle eg. acoustic neuroma => a right sided lesion will produce a slow, large-amplitude right beating nystagmus on gaze to the right (gaze-evoked nystagmus) + a left beating nystagmus of medium amplitude in the primary position (peripheral vestibular nystagmus) + a left beating fine horizontal rotatory nystagmus on gaze to the left (peripheral vestibular nystagmus)

Rebound nystagmus

- type I rebound nystagmus occurs when alcoholic patients, who have developed vestibulo-cerebellum degeneration, move their eyes into an eccentric gaze direction => this provokes gaze-evoked jerk nystagmus, which then slowly wanes, to be subsequently followed by a rebound jerk nystagmus in the opposite direction (fast phase towards the primary position of gaze - called centripetal nystagmus) while the eyes are still in the same position of eccentric gaze

- type II rebound nystagmus develops in patients with cerebellar parenchymal disease, http://www.homestead.com/emguidemaps/files/nystagmus.html (15 of 23)8/20/2004 5:15:04 PM nystagmus and occurs when the eyes return to the primary gaze position following prolonged eccentric gaze => the rapid phase of the rebound nystagmus is opposite the direction of sustained gaze

Downbeat nystagmus

- downbeat nystagmus may only occur on downgaze, and not spontaneously in the primary position of gaze

Pendular nystagmus

- there are two types of binocular conjugate nystagmus - jerk nystagmus (already described) and pendular nystagmus

- in pendular nystagmus, the to-and-fro oscillations are of equal amplitude, and there are no fast and slow phases; the slow pendular movements may be vertical, horizontal, torsional or any combination thereof

- a common form of pendular nystagmus is seen when blindness is acquired at any age, and it is called visual deprivation pendular nystagmus

- if the afferent visual system is normal, there are three common causes of pendular nystagmus

● motor nystagmus ● spasmus nutans ● ocular mycoclonus

Motor nystagmus

- due to ischemia or multiple sclerosis of the brainstem

- the symmetric pendular nystagmus may be diagonal (oblique nystagmus) and the directional vectors can continuously change (windmill nystagmus)

Spasmus nutans

- a rare triad of pendular nystagmus, torticollis and head nodding

- usually presents between the ages of 3 months and 14 months

http://www.homestead.com/emguidemaps/files/nystagmus.html (16 of 23)8/20/2004 5:15:04 PM nystagmus - usually benign, and often resolving within a few months or years

- the oscillations may be vertical, horizontal, torsional or mixed

- the pendular nystagmus may appear monocular, but a fine nystagmoid movement can often be seen in the other eye using a slit lamp or ophthalmoscope

- rarely due to optic nerve or optic chiasmal gliomas or third ventricular tumors => a MRI is always indicted to r/o rare afferent visual system tumors

Ocular mycoclonus

- continuous vertical pendular nystagmus, often occurring in association with tremulous movements of the face and palate (oculopalatal myoclonus)

- the ocular oscillations may sometimes be dysconjugate

- caused by damage to the red nucleus area in the brainstem

- the abnormal palatal tremors and pendular movements are often present during sleep

Binocular dysconjugate nystagmus

- this is a form of binocular nystagmus, where the eye movements are symmetric, but in opposite directions

- there are three common types of dysconjugate nystgamus, one involves vertical eye movements (seesaw nystagmus), and the other two involve convergence of the eyes (convergence-retraction nystagmus and convergence nystagmus)

Seesaw nystagmus

- seesaw nystagmus is the only vertical dysconjugate nystagmus

- characterized by the alternate elevation and depression of one eye accompanied by a similar movement in the other eye, but in the opposite direction (seesaw motion)

- in one half of the cycle, the rising eye also intorts and the falling eye extorts

- can occur as a congenital or acquired form

http://www.homestead.com/emguidemaps/files/nystagmus.html (17 of 23)8/20/2004 5:15:04 PM nystagmus - acquired seesaw nystagmus is most commonly due to parasellar tumors compressing the optic chiasm and/or optic nerve

- rarely due to brainstem infarcts, septo-optic dysplasia, multiple sclerosis, Arnold-Chiari malformation, syringobulbia, or head trauma

Convergence-retraction nystagmus

- convergence-retraction nystagmus with retraction of the eyeball into the socket occurs on attempted upgaze

- voluntary convergence can induce downbeat nystagmus, or convert an upbeat nystagmus into a downbeat nystagmus

- occurs as part of Parinaud's syndrome (dorsal midbrain syndrome), which is most often due to extrinsic lesions (eg. pinealoma) compressing the third ventricle area of the brainstem

- associated with near-light dissociation, failure of vertical upgaze and eyeball retraction on attempted upgaze

Convergence nystagmus

- a pendular nystagmus induced by convergence, and the nystagmus is usually convergent

- may be accompanied by eyelid nystagmus

- often accompanied by synchronous contraction of the muscles of mastication, or synchronous palate and mandibular muscle contractions (oculomasticatory myorhythmia); this oculomasticatory phenomenon is pathognomonic of Whipple's disease if it is associated with a supranuclear vertical gaze palsy

Monocular or asymmetric binocular nystagmus

- this particular sub-type of nystagmus either only involves one eye (monocular nystagmus), or involves both eyes with asymmetric involvement of the eyes (dissociated nystagmus)

- dissociated nystagmus is the term used to describe nystagmus which is different in both eyes

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- the sub-classification of dissociated nystagmus is based on whether the nystagmus occurs spontaneously in the position of primary gaze, or whether it is gaze-evoked and only occurs in an eccentric position of gaze

There are 4 types of monocular nystamus/asymmetric binocular nystagmus that occur in the primary position of gaze

Spasmus nutans

- see previous discussion of spasmus nutans

Monocular visual deprivation

- adults or children who develop monocular blindness may rarely develop monocular vertical pendular nystagmus, that can range in amplitude from fine to coarse

- the nystagmus may develop years after the visual loss, and disappear if the visual loss is corrected

- adults who acquire severe monocular visual loss (eg. due to dense cataracts) can develop monocular vertical drifts and jerk nystagmus (Heimann-Bielschowsky phenomenon) that can also disappear with recovery of vision

Superior oblique myokymia

- a monocular, small-amplitude, high frequency torsional/oblique eye movement due to tremor of the superior oblique muscle fibres

- the patient complains of episodic tilting of the image of one eye, oscillopsia or

http://www.homestead.com/emguidemaps/files/nystagmus.html (19 of 23)8/20/2004 5:15:04 PM nystagmus shimmering, or an awareness of a strange ocular movement

- the episodes only last a few seconds, but are repetitive

- the episodes may be induced by looking in the direction of action of the superior oblique muscle (downwards and inwards) or by moving the eye from that position back to the primary gaze position

- not usually associated with any other neurological findings, and the source remains unknown; very rarely due to pontine tumors or multiple sclerosis of the brainstem

Motor nystagmus of multiple sclerosis

- a low frequency pendular nystagmus involving one eye, or both eyes asymmetrically

- the vector can be multivectorial, circular, elliptical or oblique ("windmill" oscillations)

- the patient may complain bitterly of oscillopsia

- the lesion is thought to be in the brainstem or cerebellum

There is one major type of monocular nystagmus that occurs in an eccentric gaze position

Internuclear ophthalmoplegia

- INO is the most common cause of a dissociated nystagmus

- INO is seen as a lack, or lag, of movement of the adducting eye + nystagmus of the abducting eye

- other eye abnormalities may be present eg. slow adducting saccades, hypermetric abducting saccades, skew deviation and upbeat nystagmus

- INO is indicative of intrinsic brainstem pathology

- the most common cause of INO in patients < 40 years is multiple sclerosis, and the most common cause in patients > 40 years is atherosclerotic vertebro-basilar artery disease

- restrictive diseases (eg. thyroid orbitopathy) or innervation diseases (eg. myasthenia gravis) that impair eye adduction may mimic INO

http://www.homestead.com/emguidemaps/files/nystagmus.html (20 of 23)8/20/2004 5:15:04 PM nystagmus

Divergence nystagmus

- a rare divergent nystagmus where both eyes move asymmetrically away from the nose

- thought to be due to cerebellar disease

Eye movement disorders that mimic nystagmus

Saccadic oscillations

- saccadic oscillations are back-to-back involuntary saccadic eye movements without any slow phases, and they occur due to an abnormality of saccadic eye movements (in contrast to nystagmus, which occurs due to an abnormality of slow eye movements) => abnormal saccades move the eyes away from the intended position of gaze, and corrective saccades carry the eyes back

- in saccadic intrusions, such as square wave jerks and macro-square wave jerks, brief pauses occur (intersaccadic intervals) between the opposing saccades; while no intersaccadic intervals occur in ocular flutter and opsoclonus

Ocular flutter

- consist of bursts of back-to-back horizontal saccades without any intersaccadic intervals

- the bursts last a few seconds, occur in primary forward gaze, and may be precipitated by re-fixation of gaze after an eye movement

- thought to be due to a disturbance of the pause cells in the pontine paramedian reticular formation subserving horizontal eye movements

- it is almost never present without ocular dysmetria, it may appear with opsoclonus, and it probably represents a further deterioration of brainstem-cerebellar function

Opsoclonus

- opsoclonus is also called saccodomania

- opsoclonus consists of chaotic back-to-back saccades in multiple directions including horizontal, vertical and torsional; and those unpredictable high amplitude eye movements http://www.homestead.com/emguidemaps/files/nystagmus.html (21 of 23)8/20/2004 5:15:04 PM nystagmus produce the dramatic clinical picture of "dancing eyes"

- thought to be due to disruption of the cerebellar input to the paramedian pontine reticular formation

- in a young child with opsoclonus, myoclonus and cerebellar ataxia, consider an occult neuroblastoma => perform appropriate diagnostic testing; the opsoclonus may remit following successful surgery

- other causes of opsoclonus in adults include CNS tumors, parainfectious encephalitis, meningitis, CNS sarcoidosis, hydrocephalus, thalamic hemorrhage, nonketotic hyperosmolar coma, drug toxicity (lithium, haloperidol, tricyclics, phenytoin, toluene and diazepam) or multiple sclerosis

Ocular dysmetria

- manifests as a binocular conjugate saccadic undershooting or overshooting of the target during re-fixation, with a short series of oscillatory step-saccades as re-fixation occurs

- seen in cerebellar diseases, and is often associated with other cerebellar signs

Square wave jerks

- this is an ocular movement disorder manifested by an observable break in fixation because of an intrusion of a sudden unwanted saccadic movement in reflex response to an object which suddenly enters the patient's visual field, followed by a rapid return to refoveation after a nearly normal intersaccadic interval (the eye movement mimics a small amplitude horizontal nystagmus)

- secondary to neurodegenerative diseases, especially progressive supranuclear palsy and Parkinson's disease, and focal cerebral lesions

- square wave pulses (macro square waves) are large-amplitude square wave jerks seen in demyelinating diseases of the cerbellum

Macro-saccadic oscillation

- a saccadic intrusion that is really a type of saccadic dysmetria; a hypermetric saccade overshoots the target and is followed by a series of hypermetric, corrective saccades that straddle the target and gradually decrease in size until the target is fixated

http://www.homestead.com/emguidemaps/files/nystagmus.html (22 of 23)8/20/2004 5:15:04 PM nystagmus - in contrast to square wave jerks, they do not occur in darkness

- secondary to cerebellar dysfunction

Ocular bobbing

- in ocular bobbing, the eyes repeatedly move briskly downward from the primary position, remain eccentric for a few seconds, and then slowly move back to the primary position

(* the opposite of vertical downbeat nystagmus - in which the slow upward movement precedes the rapid downward movement)

- horizontal eye movements are usually absent

- indicates severe brainstem dysfunction, and is seen infrequently in comatose patients

(see the coma guidemap for more details about the different patterns of ocular bobbing)

Voluntary nystagmus

- appears as a low amplitude, high frequency pendular nystagmus that occurs in short bursts

- the pendular nystagmus is voluntarily produced, but cannot be sustained, and it will disappear if the patient is instructed to continuously keep his eyes open

- the capacity for self-induced nystagmus apparently runs in families, and it's used as a parlor-trick

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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EM guidemap - Tremor

Click on the heading or subheading to rapidly navigate to the relevant section of the guidemap

Introduction

● postural tremor

● rest tremor

● kinetic tremor

Clinical evaluation and decision-making

Appendix

● postural tremor due to metabolic disturbances or drugs

● classification and differential diagnosis of tremors

● orthostatic tremor

● rubral tremor

● brief synopsis of Parkinsonism

Introduction and general principles

- this guidemap is designed to help an emergency physician differentiate the common types of tremor

Definition: A tremor is a rhythmical, involuntary oscillatory movement of a body part that involves alternating or synchronous contractions of reciprocally innervated agonistic and antagonistic muscles

- a tremor occurs at different frequencies, and can be seen at rest and/or during action

- all true tremors usually disappear, or are markedly reduced, during sleep

- a tremor is classified according to the position that creates its maximal frequency, but it can often be seen in more than one position eg. at rest, during postural changes, or during voluntary goal-directed actions http://www.homestead.com/emguidemaps/files/tremor.html (1 of 12)8/20/2004 5:15:08 PM tremor

- action tremors occur when the muscle is actively contracting, and they include postural tremors, kinetic (intention) tremors, and isometric tremors

- the 3 major types of tremor are:- postural, rest and kinetic

Postural tremor

The tremor is maximised when the patient assumes and maintains a posture against gravity

- occurs at a frequency of 8 - 12 Hz

- may occur during movement and when holding an assumed posture against gravity

- relatively stable throughout a movement without exacerbation at the beginning or end of a task

- physiologic tremor is the most common non-pathological tremor, and it is usually asymptomatic and rarely visible, and usually most apparent in the upper extremities

- the tremor can be seen using "amplification" (such as holding a piece of paper on the outstretched hand or when pointing a hand-held laser pointer at a distant screen)

- the tremor may result from peripheral beta-sympathetic stimulation, and beta-blockers diminish the tremor

- an "enhanced" physiologic tremor is a visible postural tremor unaccompanied by neurological disease, and it occurs when a physiologic tremor is enhanced by emotional states, exercise, fatigue, withdrawal from alcohol or sedative agents, metabolic states (hyperthyroidism, hypoglycemia, pheochromocytoma, uremia, hypocalcemia, hypomagnesemia) or drugs

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Drugs that can exacerbate a physiologic tremor

alcohol, anticonvulsants, amphetamines, arsenic, beta- sympathomimetic agents, bismuth, butyrophenones, caffeine, carbon monoxide, dopamine agonists, epinephrine. fluoxetine, haloperidol, heavy metals, hypoglycemic agents, lead, levodopa, lithium, mercury, methylbromide, methylphenidate, metoclopromide, monosodium glutamate, neuroleptics, phenothiazines, phenylpropanolamine, pseudoephedrine steroids, terbutaline sulfate, theophylline, thyroid hormones, tricylic antidepressants, valproic acid

Because an "enhanced" physiologic tremor is the most common cause of a postural action tremor, one should search for medical diseases causing tremor-enhancement, rather than a primary neurological disease

- the "enhanced" physiologic tremor disappears on elimination of the enhancing factor

- as there are no biomarkers to differentiate physiologic tremor from essential tremor, a visible postural tremor of the upper extremities in the absence of identifiable enhancing factors is currently classified as an essential tremor

- an essential tremor is the most common pathological cause of a postural tremor

Characteristics of essential tremor

● familial in 50% of cases, sporadic in the rest of the cases ● usually starts when patients are in their adolesence or 30 - 40's, progresses with age, remains a life-long illness ● tremor may be asymmetric and transient initially ● established tremors are often bilateral and symmetric and mainly postural ● tremor frequency of 4 - 12Hz; tremor frequency increases with time ● a kinetic component is common and the tremor is accentuated with movement and the assumption of a posture; a rest component is less frequent; tremor disappears during sleep ● usually involves the upper limbs (90%), and rarely the head (50%), neck, chin (15%) or voice (30%) - causing a shaky, wavering voice ● tremor amplitude may transiently worsen with stress, fatigue,

http://www.homestead.com/emguidemaps/files/tremor.html (3 of 12)8/20/2004 5:15:09 PM tremor sexual arousal, CNS stimulation, or exposure to extreme temperatures ● tremor amplitude can also worsen with goal-directed activities requiring precise movements eg. drinking from a cup, writing ● monosymptomatic, with no other abnormal neurological signs other than occasional tandem gait difficulties ● aggravated by certain nor-adrenergic medications ● may be temporarily relieved by relaxation, mental concentration, or alcohol => possible rebound when alcohol wears-off ● one first needs to exclude other causes of postural tremor due to metabolic disturbances or medications before diagnosing essential tremor

- the core criteria for an essential tremor are:- bilateral action tremor of the hands and forearms in the absence of other neurological signs other than "cog-wheeling" (an oscillation of resistance during passive movement thought due to be due to the tremor) and tandem gait disturbances

- secondary criteria include:- long duration (> 3 years), positive family history and beneficial response to alcohol

- signs that suggest a disorder other than essential tremor include:- unilateral tremor; isolated chin or voice or leg tremors; combination of rigidity, bradykinesia, rest tremor (suggests Parkinson's disease); sudden onset or step-wise progression (suggests stroke, MS or psychogenic etiology); gait abnormalities (suggests MS, stroke or Parkinson's disease) and the presence of enhancing drugs (suggests an "enhanced" physiologic tremor)

Rest tremor

Occurs when a limb is in maximal repose, and supported against gravity, so that the limb muscles are not actively contracting

- usually involves the upper limbs, and often the distal limb - thumb abducts-adducts and fingers flex-extend and the forearm supinates-pronates producing a "pill-rolling" movement

- frequency of 3 - 7Hz

- the most common cause of rest tremor is Parkinson's disease, which is suggested by an asymmetrical tremor and associated bradykinesia, rigidity and postural instability (the http://www.homestead.com/emguidemaps/files/tremor.html (4 of 12)8/20/2004 5:15:09 PM tremor tremor may precede the other neurological signs; the tremor often disappears, or markedly lessens, with voluntary movement or mental concentration)

- even the most severe rest tremor, due to Parkinsons disease, disappears during finger- nose testing

- the tremor may spread to the legs, face and chin, but Parkinson's disease does not cause a head tremor (head titubation)

- other common causes of rest tremor include Parkinsons plus syndromes, medications having extra-pyramidal side-effects (neuroleptics, reserpine, metoclopromide, perhexiline, tetrabenazine), Wilson's disease, non-Wilsonian hepatocerebellar degeneration, midbrain pathology secondary to stroke or demyelinating disease, carbon monoxide poisoning, and heavy metal poisoning

Kinetic (intention) tremor

The tremor only occurs during action and is accentuated with voluntary movements

- the slow (2 - 5 Hz) tremor may show marked irregularity due to varying tremor amplitude during an action => the tremor may worsen when approaching the endpoint of a visually guided, goal-directed movement (intention tremor)

(* the tremor is side-to-side, and opposite to the main direction of the intended movement; the kinetic tremor paradoxically worsens when done under visual guidance, in comparison to when the same movement is performed with proprioceptive cues alone)

- the most common cause of a kinetic intention tremor is cerebellar disease (eg. MS or cerebellar infarction or cerebellar degenerative diseases), or a chronic relapsing polyneuropathy

- less common causes of tremor include:- isometric tremor, which is evoked by voluntary isometric muscle contractions without movement eg. clenching a fist, holding up a weight, pushing hands against a wall; and a task-specific tremor, which only occurs during performance of a specific task

Clinical evaluation and decision-making

The main purpose of the clinical evaluation is to determine whether the tremor mainly occurs at rest, or mainly occurs during the adoption of a posture, or mainly

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The accurate classification of a tremor as a rest tremor, or postural tremor, or intention tremor will probably suggest the likely etiology

- first observe the patient at rest, with his arms supported against gravity in his lap to determine whether a rest tremor is present

- if a rest tremor is present => check for other signs of Parkinsons disease (bradykinesia, rigidity, gait difficulties)

(* see the appendix for a brief synopsis of Parkinsons disease)

- then ask the patient to lift his arms upwards with palms facing-up, and observe for any postural tremors => ask the patient to turn his palms down and observe for any postural tremor => ask the patient to move his elbows out into a "wing beating" position, so that the opposing fingertips are facing each other, and observe for postural tremors

(* rest tremors may re-appear after the action is completed and the adopted posture is passively supported against gravity, but the tremors should be less prominent during the action)

- then check for intention tremors of the upper limb during finger-nose pointing, and intention tremors of the lower limbs by heel-knee testing

- an action tremor that is much worse at the very end of a goal-directed movement (after a new posture is adopted) suggests an essential tremor (postural tremor), while cerebellar intention tremors produce steadily increasing oscillations before the target is even reached, and the tremor is usually at its worst before the end of a goal-directed movement is reached

- if an intention tremor is present => check for other signs of cerebellar disease eg. dysarthria, dysmetria, dyssynergia, dysdiadochokinesis, nystagmus, ataxia and hypotonia

(* cerebellar tremors are usually bilateral and symmetric, and often involve the proximal limb producing coarse tremors; an unilateral cerebellar tremor suggests unilateral cerebellar infarction or tumor)

- if a patient complains of leg tremors suggestive of orthostatic tremor (variant of essential tremor) => ask the patient to stand and palpate the thighs for quivering (which may be palpable and not visible) => ask the patient to walk, which is usually not a problem (in contrast to patients with cerebellar tremors affecting the lower limbs, which are often http://www.homestead.com/emguidemaps/files/tremor.html (6 of 12)8/20/2004 5:15:09 PM tremor

associated with ataxia)

(* see the appendix for more features of orthostatic tremors)

- check for head tremors (horizontal "no-no", or vertical "yes-yes"), which suggests an essential tremor in the absence of cerebellar signs

- finally, check for task-related tremors eg. lifting a cup, writing, drinking, eating

(* many tremors are worse during writing, but a tremor that is only present during writing suggests a primary writing tremor disorder)

- if the tremor mainly occurs at rest and is asymmetric with no other abnormal neurological signs => suggests early Parkinson's disease

- if the tremor is postural, first consider metabolic conditions or drugs causing an "enhanced"physiologic" tremor, before diagnosing essential tremor

- if the tremor is present both at rest and on adopting a posture, look carefully for evidence of bradykinesia or micrographia, which suggests Parkinson's disease (rather than an essential tremor)

- other clinical clues relate to tremor frequency

● 2 - 4 Hz => cerebellar or rubral tremor ● 4 - 8 Hz => Parkinsonian tremor (rarely an essential tremor) ● 8 - 10 Hz => essential tremor or physiologic tremor

- tremor amplitude may also be a helpful clue

● fine tremor => parkinsonism or essential tremor ● coarse tremor => cerebellar or rubral tremor ● wing-beating tremor => Wilson's disease

- certain features suggest a psychogenic tremor

● sudden onset of tremors, sudden remission, or both ● unusual combinations of resting, postural and kinetic tremors (difficult to classify) ● changing tremor frequency ● decreased tremor amplitude with distraction ● increased tremor amplitude with attention

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● variation of tremor frequency with distraction or during voluntary movements of the opposite limb ● history of somatization ● unresponsiveness to anti-tremor drugs ● responsiveness to placebo agents ● remission with successful psychotherapy

- routine laboratory testing to r/o Wilson's disease or an endocrinopathy (hypoglycemia or hyperthyroidism or pheochromocytoma or hypoparathyroidism) is rarely necessary

Appendix

Postural tremor due to metabolic disturbances or drugs Metabolic disturbances

● hyperthyroidism ● hyperparathyroidism ● withdrawal from alcohol or drugs ● Wilson's disease ● vitamin B12 deficiency ● renal failure ● pheochromocytoma

Medications

● beta agonists ● theophylline ● sodium valproate ● tricyclic antidepressants ● lithium ● selective serotonin reuptake inhibitors (SSRIs) ● steroids ● cyclosporin and other immunosuppressants ● dopamine agonists ● metoclopromide ● amiodarone ● oral contraceptives ● thyroid hormone

Drugs

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● cocaine ● caffeine ● amphetamines ● nicotine ● stimulants

Classification and differential diagnosis of tremors Rest tremors

● Parkinsons disease ● other Parkinsonian syndromes (less common) ● rubral tremor (rest < postural < kinetic) ● Wilsons disease ● essential tremor (only if severe, rest << postural or action)

Postural tremors

● physiologic tremor ● "enhanced" physiologic tremor ● essential tremor ● task-specific tremor ● due to CNS disorders (parkinson's disease, other akinetic rigidity syndromes, idiopathic dystonia, rubral tremor) ● due to peripheral neuropathy (Charcot-Marie Tooth syndrome, diabetes, recovery phase of Guillane-Barre, porphyria, IgM dysgammaglobulinemias) ● Wilson's disease

Kinetic (intention) tremor

● cerebellar disease (MS, infarction, drugs, toxins, degenerative disorders) ● chronic relapsing polyneuropathy ● Wilson's disease ● rubral tremor

Miscellaneous rhythmical disorders

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● psychogenic tremor ● orthostatic tremor ● dystonic tremor ● rhythmical segmental myoclonus ● oscillatory myoclonus ● asterixis ● clonus ● epilepsia partialis continua ● hereditary chin quivering ● spasmus nutans ● head bobbing with 3rd ventricular cysts

Orthostatic tremor

- the tremor involves the trunk and lower limbs and only occurs when standing

- when asked to stand in one place, the patient develops hard cramping calves and thighs and shakes uncontrollably

- lifting the patient off the ground abolishes the tremor

- the patient can usually walk normally with only mild discomfort, and trembling disappears from the non-weight bearing leg during ambulation

- standing on "all fours" can also induce trembling in proximal arm muscles

- the patient can sit without lower limb trembling

Rubral tremor ("Holmes" tremor)

- the tremor may be present at rest, but is usually most prominent on action or posture, with a prominent intention tremor component

- slower, and more irregular than other tremors, and of greater amplitude (coarse, jerky tremor)

- usually due to midbrain disease (Benedikt's syndrome), thalamic pathology or cerebellar outflow pathway disease

- if due to midbrain disease, the tremor is ipsilateral to the side of the lesion

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- accompanied by other abnormal neurological signs, which vary dependent on the site of the pathology

Brief synopsis of Parkinsonism

- some causes of Parkinsonism:-

● Parkinson's disease (idiopathic) ● encephalitis lethargica ● drug-induced Parkinsonism (phenothiazines, butyrophenones, reserpine, metoclopromide) ● toxin-induced Parkinsonism (manganese dust, carbon disulfide or carbon monoxide) ● MPTP (1-methyl-4-phenyl-1,2,5, 6-tetrahydropyridine) - a synthetic mepiridine analogue ● Parkinsonism associated with other neurological diseases (Parkinsons plus syndromes)

- clinical features of Parkinson's disease include rest tremor, rigidity, bradykinesia, masklike facies (hypomimia), low volume unmodulated voice (hypophonia), stooped posture on standing, inertia of gait initiation, small shuffling step gait with absence of normal arm swinging, festinant gait (flexed posture walking with rapidly increasing speed to prevent falling), fluttering of the closed eyelids (blepharoclonus), occasional involuntary closure of the eyelids (blepharospasm)

- the three cardinal features of Parkinson's disease include rest tremor, rigidity and bradykinesia (2-out-of-3 needed for the diagnosis)

- the rigidity is lead-pipe or cog-wheeling in type (due to associated tremor)

- the bradykinesia refers to slowness of movement, and paucity of spontaneous movements, and decreased amplitude of movements

- postural instability refers to imbalance and loss of righting reflexes, and is a later develoment

- dementia occurs later in 15 - 30% of patients

- dyskinesia may occur due to levo-dopa therapy; the dyskinesia may be choreoathetotic, ballistic, dystonic or myoclonic, and may vary from mild to severe

http://www.homestead.com/emguidemaps/files/tremor.html (11 of 12)8/20/2004 5:15:09 PM tremor - sensory complaints include paresthesia, cold sensations, sensations of shortness of breath without actual respiratory abnormalities, aching and frank pain

- akathisia is common in young patients, and severely affected patients may be compelled to remain in constant motion, unable to remain still for even a minute

- restless leg syndrome is characterised by the presence of nocturnal leg dysesthesias and restless irrestible sterotyped leg movements which lead to sleep deprivation

- differential diagnosis of Parkinson's disease includes:-

● diffuse Lewy body disease

● Wilson's disease

● Huntingdon's disease

● Shy-Drager syndrome (Multiple system atropy)

● Striatoniagral degeneration

● progressive supranuclear palsy ● cortical basal ganglionic degeneration

● Creutzfeldt-Jakob disease ● normal pressure hydrocephalus

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing clinical cases in an ED setting and they should not be regarded as the standard of care. They merely represent the personal opinions of the author and they should only be used in clinical practice if the reader-user has substantial reason to believe that the clinical advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be "authoritative" and the reader-user should consult standard medical textbooks and expert opinion articles/guidelines for more authoritative advice. The reader-user should particularly confirm all drug doses, their indications and contra-indications, prior to their use.

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Back to: eMedicine Specialties > Neurology > Introductory Topics Quick Find Author Information Cauda Equina and Conus Medullaris Syndromes Rate this Article Introduction Clinical Email to a Differentials Last Updated: August 2, 2004 Colleague Workup Synonyms and related keywords: lower spinal cord injury, compressive lumbosacral polyradiculopathy Treatment Medication Follow-up AUTHOR INFORMATION Section 1 of 11 Miscellaneous Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Pictures Bibliography

Author: Segun T Dawodu, MD, FAAPMR, FAAEM, CIME, Former Clinical Instructor, Mount Sinai Hospital; Click for related Director, Pain and Injuries Rehabilitation Services, PMRehab Pain & Sports Medicine Associates images.

Coauthor(s): Nicholas Lorenzo, MD, eMedicine Chief Publishing Officer, Chief Editor, eMedicine Neurology; Related Articles Consulting Staff, Neurology Specialists and Consultants

Segun T Dawodu, MD, FAAPMR, FAAEM, CIME, is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Electrodiagnostic Medicine, American College of Sports Medicine, American Medical Association, American Medical Informatics Association, Association of Academic Physiatrists, International Society of Physical and Rehabilitation Medicine, International Spinal Injection Society, and Royal College of Surgeons of Edinburgh

http://www.emedicine.com/neuro/topic667.htm (1 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME Editor(s): Milind J Kothari, DO, Program Director, Associate Professor, Department of Internal Medicine, Division Acute Inflammatory of Neurology, Pennsylvania State University Hershey Medical Center; Francisco Talavera, PharmD, PhD, Senior Demyelinating Pharmacy Editor, Pharmacy, eMedicine; , Professor, Department of Neurology, University of James H Halsey, MD Polyradiculoneuropathy Alabama Medical Center; Selim R Benbadis, MD, Director of Comprehensive Epilepsy Program, Associate Professor, Departments of Neurology and Neurosurgery, University of South Florida, Tampa General Hospital; and Alcohol (Ethanol) Helmi L Lutsep, MD, Associate Director, Oregon Stroke Center, Associate Professor, Department of Neurology, Oregon Health Sciences University Related Neuropathy

INTRODUCTION Section 2 of 11 Amyotrophic Lateral Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Sclerosis

Chronic Inflammatory The spinal cord tapers and ends at the level between the first and second lumbar vertebrae in an Background: Demyelinating average adult. The most distal bulbous part of the spinal cord is called the conus medullaris, and its tapering end continues as the filum terminale. The upper border of the conus medullaris is often not well defined. Distal to this end Polyradiculoneuropathy of the spinal cord is a collection of nerve roots, which are horsetail-like in appearance and hence called the cauda equina (Latin for horse's tail). These nerve roots constitute the anatomic connection between the central nervous Dermatomyositis/ system (CNS) and the peripheral nervous system (PNS). They are arranged anatomically according to the spinal Polymyositis segments from which they originated and are within the cerebrospinal fluid (CSF) in the subarachnoid space with the dural sac ending at the level of second sacral vertebra. Diabetic Neuropathy

Pathophysiology: The conus medullaris part of the spinal cord obtains its blood supply primarily from 3 spinal Femoral arterial vessels - the anterior median longitudinal arterial trunk and 2 posterolateral trunks. Less prominent sources of Mononeuropathy blood supply include radicular arterial branches from the aorta, lateral sacral arteries, and the fifth lumbar, iliolumbar, and middle sacral arteries. The latter contribute more to the vascular supply of the cauda equina, although not in a HIV-1 Associated segmental fashion, unlike the blood supply to the peripheral nerves. The nerve roots may also be supplied by Distal Painful diffusion from the surrounding CSF. Moreover, a proximal area of the nerve roots may have a zone of relative hypovascularity. Sensorimotor Polyneuropathy In understanding the pathological basis of any disease involving the conus medullaris, keep in mind that this structure constitutes part of the spinal cord (the distal part of the cord) and is in proximity to the nerve roots. Thus, HIV-1 Associated injuries to this area often yield a combination of upper motor neuron (UMN) and lower motor neuron (LMN) Multiple symptoms and signs in the dermatomes and myotomes of the affected segments. On the other hand, a cauda equina Mononeuropathies lesion is a LMN lesion because the nerve roots are part of the PNS. Cauda equina and conus medullaris syndromes are classified as clinical syndromes of the spinal cord; epidemiological data on the 2 syndromes are often not HIV-1 Associated available separately from the general data on spinal cord injury. Myopathies

Frequency: HIV-1 Associated Neuromuscular ● In the US: Frequency is determined by the underlying etiology. Multiple conditions can result in a cauda equina or conus medullaris syndrome as outlined later in this article. Complications (Overview) http://www.emedicine.com/neuro/topic667.htm (2 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

Mortality/Morbidity: Morbidity and especially mortality rates are determined by the underlying etiology. Multiple conditions can result in cauda equina or conus medullaris syndrome, as outlined later in this article. Multiple Sclerosis

Neurosarcoidosis CLINICAL Section 3 of 11

Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Pathophysiology of Chronic Back Pain

History: The history of onset, the duration of symptoms, and the presence of other features or symptoms could point Spinal Cord to the possible causes. Patients can present with symptoms of isolated cauda equina syndrome, isolated conus Hemorrhage medullaris syndrome, or a combination. The symptoms and signs of cauda equina syndrome tend to be mostly LMN in nature, while those of conus medullaris syndrome are a combination of LMN and UMN effects (Table 1). Spinal Cord Infarction Table 1. Symptoms and Signs of Conus Medullaris and Cauda Equina Syndromes Spinal Cord Trauma and Related Diseases Conus Medullaris Syndrome Cauda Equina Syndrome Presentation Sudden and bilateral Gradual and unilateral Spinal Epidural Knee jerks preserved but ankle Abscess Reflexes Both ankle and knee jerks affected jerks affected Syringomyelia Radicular pain Less severe More severe Low back pain More Less Traumatic Peripheral Numbness tends to be more Nerve Lesions localized to saddle area; asymmetrical, may be unilateral; no Tropical Numbness tends to be more sensory dissociation; loss of Sensory symptoms and localized to perianal area; Myeloneuropathies sensation in specific dermatomes in signs symmetrical and bilateral; sensory lower extremities with numbness dissociation occurs and paresthesia; possible numbness in pubic area, including Continuing glans penis or clitoris Education Typically symmetric, hyperreflexic Asymmetric areflexic paraplegia CME available for distal paresis of lower limbs that is Motor strength that is more marked; fasciculations this topic. Click less marked; fasciculations may be rare; atrophy more common here to take this present CME.

Patient Education

http://www.emedicine.com/neuro/topic667.htm (3 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME Less frequent; erectile dysfunction Erectile that includes inability to have Dysfunction Center erection, inability to maintain Impotence Frequent erection, lack of sensation in pubic Impotence/Erectile area (including glans penis or clitoris), and inability to ejaculate Dysfunction Introduction Urinary retention and atonic anal sphincter cause overflow urinary Urinary retention; tends to present Impotence/Erectile Sphincter dysfunction incontinence and fecal late in course of disease incontinence; tend to present early Dysfunction in course of disease Causes

Impotence/Erectile Physical: The symptoms described in History are associated with corresponding signs pointing to an LMN or UMN lesion. Refer to Images 1-2 for assistance in examining the patient and documenting examination findings. In addition Dysfunction to the signs listed below, signs of other possible causes should be sought (eg, examination of the peripheral pulses Medical Treatment to rule out possible vascular cause or ischemia of the conus medullaris). Impotence/Erectile

● Signs of cauda equina syndrome include the following: Dysfunction Surgical Treatment

❍ Muscle strength in the lower extremities is diminished. This may be specific to the involved nerve roots as listed below, with the lower lumbar and sacral roots more affected, leading to diminished strength in Erectile the glutei muscles, hamstring muscles (ie, semimembranosus, semitendinosus, biceps femoris), and Dysfunction FAQs the gastrocnemius and soleus muscles.

❍ Sensation is decreased to pinprick and light touch in a dermatomal pattern corresponding to the affected nerve roots. This includes saddle anesthesia (sometimes including the glans penis or clitoris) and decreased sensation in the lower extremities in the distribution of lumbar and sacral nerves. Vibration sense may also be affected. Sensation of the glans penis or clitoris should be examined.

❍ Muscle stretch reflexes may be absent or diminished in the corresponding nerve roots. Babinski reflex is diminished or absent.

❍ Bulbocavernosus reflexes may be absent or diminished. This should always be tested.

❍ Anal sphincter tone is patulous and should always be tested since it can define the completeness of the injury (with bulbocavernosus reflex); it is also useful in monitoring recovery from the injury.

❍ Urinary incontinence could also occur secondary to loss of urinary sphincter tone; this may also present initially as urinary retention secondary to a flaccid bladder. http://www.emedicine.com/neuro/topic667.htm (4 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

❍ Muscle tone in the lower extremities is decreased, which is consistent with an LMN lesion.

● Signs of conus medullaris syndrome include the following:

❍ Patients may exhibit hypertonicity, especially if the lesion is isolated and primarily UMN.

❍ Signs are almost identical to those of the cauda equina syndrome, except that in conus medullaris syndrome signs are more likely to be bilateral; sacral segments occasionally show preserved bulbocavernosus reflexes and normal or increased anal sphincter tone; the muscle stretch reflex may be hyperreflexic, especially if the conus medullaris syndrome (ie, UMN lesion) is isolated; Babinski reflex may affect the extensors; and muscle tone might be increased (ie, spasticity).

❍ Other signs include papilledema (rare, occurs in lower spinal cord tumors), cutaneous abnormalities (eg, cutaneous angioma, pilonidal sinus that may be present in dermoid or epidermoid tumors), distended bladder due to areflexia, and other spinal abnormalities (noted on lower back examination) predisposing the patient to the syndrome.

● Muscle strength of the following muscles should be tested to determine the level of lesion:

❍ L2 - Hip flexors (iliopsoas)

❍ L3 - Knee extensors (quadriceps)

❍ L4 - Ankle dorsiflexors (tibialis anterior)

❍ L5 - Big toe extensors (extensor hallucis longus)

❍ S1 - Ankle plantar flexors (gastrocnemius/soleus)

● In defining impairments associated with a spinal cord lesion, the American Spinal Cord Injury Association (ASIA) impairment scale is used in determining the level and extent of injury.

❍ This scale should also be used in defining the extent of conus medullaris syndrome/cauda equina syndrome; the scale is as follows:

■ A - Complete; no sensory or motor function preserved in sacral segments S4-S5

■ B - Incomplete; sensory, but not motor, function preserved below the neurologic level and extends through sacral segments S4-S5 http://www.emedicine.com/neuro/topic667.htm (5 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

■ C - Incomplete; motor function preserved below the neurologic level, and the majority of key muscles below the neurologic level have a muscle grade less than 3

■ D - Incomplete; motor function preserved below the neurologic level, and the majority of key muscles below the neurologic level have a muscle grade greater than or equal to 3

■ E - Normal; sensory and motor function normal

❍ The injury should be described using this scale, for example, ASIA class A. Most patients with cauda equina/conus medullaris syndrome are in ASIA class A or B initially and gradually improve to class C, D, or E.

Table 2. Root and Peripheral Nerve Innervation of the Lumbosacral Plexus

Muscle Nerve Root

lliopsoas Femoral L2, 3, 4

Adductor longus Obturator L2, 3, 4

Gracilis Obturator L2, 3, 4

Quadriceps femoris Femoral L2, 3, 4

Anterior tibial Deep peroneal L4, 5

Extensor hallucis longus Deep peroneal L4, 5

Extensor digitorum Deep peroneal L4,5 longus

Extensor digitorum Deep peroneal L4, 5, S1 brevis

Superficial Peroneus longus L5, S1 peroneal

Internal hamstrings Sciatic L4, 5, S1 http://www.emedicine.com/neuro/topic667.htm (6 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

External hamstrings Sciatic L5, S1

Gluteus medius Superior gluteal L4, 5, S1

Gluteus maximus Inferior gluteal L5, S1, 2

Posterior tibial Tibial L5, S1

Flexor digitorum longus Tibial L5, S1

Tibial (medial Abductor hallucis brevis L5, S1, 2 plantar)

Abductor digiti quinti Tibial (lateral S1, 2 pedis plantar)

Gastrocnemius lateral Tibial L5, S1, 2

Gastrocnemius medial Tibial S1, 2

Soleus Tibial S1, 2

Causes: The most common causes of cauda equina and conus medullaris syndromes are the following:

● Lumbar stenosis (multilevel)

● Spinal trauma including fractures

● Herniated nucleus pulposus (cause of 2-6% of cases of cauda equina syndrome)

● Neoplasm, including metastases, astrocytoma, neurofibroma, and meningioma: Twenty percent of all spinal tumors affect this area.

● Spinal infection/abscess, including tuberculosis, herpes simplex virus, meningitis, meningovascular syphilis, cytomegalovirus, schistosomiasis

● Idiopathic, eg, spinal anesthesia: These syndromes may occur as complications of the procedure or of the anesthetic agent (eg, hyperbaric lidocaine, tetracaine). http://www.emedicine.com/neuro/topic667.htm (7 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

● Spina bifida and tethered cord syndrome

● Other, rare causes

❍ Spinal hemorrhage, especially subdural and epidural hemorrhage causing compression within the spinal canal

❍ Intravascular lymphomatosis

❍ Congenital anomalies of the spine/filum terminale

❍ Conus medullaris lipomas

❍ Multiple sclerosis

❍ Spinal arteriovenous malformations

❍ Late-stage ankylosing spondylitis

DIFFERENTIALS Section 4 of 11

Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Acute Inflammatory Demyelinating Polyradiculoneuropathy Alcohol (Ethanol) Related Neuropathy Amyotrophic Lateral Sclerosis Chronic Inflammatory Demyelinating Polyradiculoneuropathy Dermatomyositis/Polymyositis Diabetic Neuropathy Femoral Mononeuropathy HIV-1 Associated Distal Painful Sensorimotor Polyneuropathy HIV-1 Associated Multiple Mononeuropathies HIV-1 Associated Myopathies HIV-1 Associated Neuromuscular Complications (Overview) Multiple Sclerosis Neurosarcoidosis Pathophysiology of Chronic Back Pain http://www.emedicine.com/neuro/topic667.htm (8 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME Spinal Cord Hemorrhage Spinal Cord Infarction Spinal Cord Trauma and Related Diseases Spinal Epidural Abscess Syringomyelia Traumatic Peripheral Nerve Lesions Tropical Myeloneuropathies

Other Problems to be Considered:

Abdominal aortic aneurysm Amyloidosis with deposits in the spinal cord Ankylosing spondylitis and other spondyloarthropathy Charcot-Marie-Tooth disease (types 1 and 3) Guillain-Barré syndrome Herniated lumbar or sacral disk Intravascular lymphomatosis Lipomas within the spine Lumbar stenosis (multilevel) Neoplasm in the spine Paget disease of the spine Peripheral neuropathy and its various causes Retroperitoneal mass, including neoplasm and hematoma Sacral plexus injury (eg, after surgery, such as abdominal-perineal resection, sacral excision, or radical hysterectomy) Spinal infection/abscess and meningitis Spina bifida/congenital anomalies of the spine/filum terminale Spinal degenerative diseases Spinal hemorrhage Spondylolisthesis Tethered cord syndrome/short filum terminale Vascular intermittent claudication Back pain

http://www.emedicine.com/neuro/topic667.htm (9 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

WORKUP Section 5 of 11

Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Lab Studies:

● These studies may help to define possible causes and any associated pathology, especially other causes of lesions in the lower spinal cord or cauda equina.

❍ CBC, blood glucose, electrolytes, blood urea nitrogen (BUN), and creatinine - As part of the workup to rule out associated anemia, infection, and renal dysfunction, especially in associated retroperitoneal mass

❍ Elevated erythrocyte sedimentation rate (ESR) - May point to an inflammatory pathology

❍ Syphilitic serology to rule out meningovascular syphilis

Imaging Studies:

● MRI with contrast of the lumbosacral spine is the diagnostic test of choice and provides a more complete radiographic assessment of the spine than other tests. Gadolinium contrast MRI is currently the most sensitive imaging for detecting intradural neoplasms. It also may be able to rule out abdominal aneurysm, which could be the source of emboli causing conus medullaris infarction. See Images 3-5 for representative MR images.

● CT scan myelogram may reveal an intradural or extradural mass or lesions affecting the conus medullaris.

● Plain radiographs of the lumbosacral spine are still useful and may depict early changes in vertebral erosions secondary to tumors and spina bifida. Chest radiography is indicated to rule out a pulmonary source of pathology that could affect the lumbosacral spine (eg, malignant tumor, tuberculosis). Follow-up chest CT may be required.

● Bone scan may detect malignant tumor or metastases and inflammatory conditions affecting the vertebrae.

Other Tests:

● Needle electromyography (EMG) may show evidence of acute denervation, especially in cauda equina lesions and multilevel lumbar spinal stenosis. EMG studies also could help in predicting prognosis and monitoring recovery.

● Nerve conduction studies, especially of the pudendal nerve, may rule out more distal peripheral nerve lesions. http://www.emedicine.com/neuro/topic667.htm (10 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

● Somatosensory evoked potentials (SSEPs) could be done as part of the workup to rule out multiple sclerosis, which could present initially as a lower spinal cord syndrome.

● Duplex ultrasound of peripheral vessels may rule out compromised vasculature as a possible cause of associated claudication.

Procedures:

● Lumbar puncture - Examination of the CSF to rule out inflammatory disease of the meninges or spinal cord

TREATMENT Section 6 of 11

Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography

Medical Care: Specific treatment is directed at the primary cause; these are discussed in other articles. As discussed below, the general treatment goals are to minimize the extent of injury and to treat ensuing general complications.

● Acute care: In an acute setting, treatment options entail minimizing possible inflammation and preventing further trauma that might cause worsening of the injury. This is of even greater importance if the cause is trauma.

❍ Maintenance of adequate airway, cardiopulmonary resuscitation, fluid management, and initial immobilization (using a molded thoracolumbosacral orthosis) are necessary to limit further damage.

❍ Methylprednisolone should be administered as indicated in Medication. This treatment must be started within 8 hours of injury. No evidence exists of any benefit if it is started more than 8 hours after injury; on the contrary, late treatment may have detrimental effects.

❍ Administration of GM1 ganglioside sodium salt beginning within 72 hours of injury may be beneficial; the dose is 100 mg IV qd for 18- 32 days.

❍ Tirilazad mesylate (a nonglucocorticoid 21-aminosteroid) has been proven to be of benefit in animals and is currently under investigation. It inhibits lipid peroxidation and hydrolysis in the same manner as glucocorticoids.

● Any specific causal factor should be treated as soon as it has been identified.

● Treatment/prevention of possible complications should begin immediately, including the following:

❍ Deep venous thrombosis/pulmonary embolism: Patients should use antiembolic compression stockings and subcutaneous heparin for 3 months as prophylaxis. Low-molecular-weight heparin also has been approved for prophylaxis. Ultrasound of the lower extremities may need to be done as an initial screening test with follow-up later. http://www.emedicine.com/neuro/topic667.htm (11 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

❍ Neurogenic bladder: Patients may require bladder catheterization.

❍ Pressure ulcers: These may be prevented by eliminating pressure, optimizing wound-healing environment, and debriding if necessary.

❍ Impotence: Use of sildenafil (Viagra) is becoming popular. Other drugs include yohimbine, papaverine, and alprostadil. Methods to promote coitus and/or ejaculation could also be used; these include implantable penile prostheses or vibrator stimulation.

❍ Fecal incontinence: Patients may require use of stool softener or manual evacuation.

❍ Heterotopic ossification: Heterotropic ossification (HO) can be confirmed by a triple-bone scan with associated elevated alkaline phosphatase and phosphate, especially in the early stage. Treatment includes stretching exercises, disodium etidronate (20 mg/kg qd x 2 wk, then 10 mg/kg for as long as 12 wk), radiation, and surgical excision. Surgery is done only when the HO has matured or stabilized, which is evident by stable plain x-ray, normal alkaline phosphatase level, and decline in triple-phase bone scan activity.

❍ Pain: Pain should be treated appropriately based on its origin; treatment may include narcotics in the acute setting and tricyclic antidepressants later. Patient education, biofeedback, and relaxation techniques may also be used.

❍ Spasticity: Use of orthoses is advised to prevent contractures. Use of antispasticity medications also is encouraged. Other medications include dantrolene, diazepam, clonidine, and tizanidine. Nerve blocks also could be done to relieve spasticity; appropriate agents include phenol, botulinum toxin, or local anesthetics.

Surgical Care: In acute compression of the conus medullaris or cauda equina, surgical decompression as soon as possible (preferably within 6 h of injury) becomes mandatory. In a more chronic presentation with less severe symptoms, decompression could be performed when medically feasible and should be delayed to optimize the patient's medical condition; with this precaution, decompression is less likely to lead to irreversible neurological damage.

● Surgical treatment may be necessary for decompression or tumor removal, especially if the patient presents with acute onset of symptoms. Surgical treatment may include any of the following:

❍ Laminectomy and instrumentation/fusion for stabilization

❍ Discectomy

● Other surgical care may entail wound care, eg, debridement, skin graft, and skin flap/myocutaneous flap.

Consultations: Consultations to different specialties are needed for acute care and follow-up care.

● Urgent consults for follow-up and advice of the following specialists may be required: http://www.emedicine.com/neuro/topic667.htm (12 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

❍ Neurosurgery/spinal orthopedics - To assess the need for urgent surgical spinal decompression

❍ Plastic surgery - May be needed if severe skin breakdowns occur

❍ Rehabilitation - For initial consultation to prevent possible complications, including contractures and advising on bladder/bowel management, wound management, and prescribing the required physical therapy/occupational therapy and assistive devices; this would include follow-up, involvement of social workers, and vocational rehabilitation experts for home adaptation (needed on discharge).

❍ Dietitian - To advise on optimizing the diet to ensure adequate calorie and protein intake. Patients with these syndromes often have an increase in metabolism associated with the healing process.

Diet: See Consultations.

Activity: The rehabilitation team, especially the spinal cord injury rehabilitation physician and occupational and physical therapists, should be involved as soon as possible.

● This entails setting goals in the rehabilitation unit toward maintaining and improving endurance, with the ability to be independent in activities of daily living on discharge from the hospital or long-term care facility.

● The rehabilitation goals are to maximize the medical, physical, psychological, educational, vocational, and social function of the patient. This involves the following rehabilitation modalities:

❍ Medical - Ensure adequate prevention and treatment of possible medical complications already discussed, especially deep venous thrombosis, bladder and bowel problems, and decubitus ulcers

❍ Physical therapy - Range of motion and strengthening exercises, sitting balance, transfer training, and tilt table as tolerated (because of tendency to orthostatic hypotension). Tilt table should start at 15 degrees, progressing by 10 degrees every 15 minutes up to about 80 degrees with the necessary precautions. Other activities include wheelchair propulsion training, standing table exercises, functional electrical stimulation for increased muscle tone, use of lower extremity orthoses to aid balance and walking, along with ambulation exercises, family training and community skills, and a home exercise program.

❍ Occupational therapy - Wheelchair training, especially for advanced wheelchair activities; transfer training; activities of daily living program with assistive devices for dressing, feeding, grooming, bathing, and toileting; motor coordination skills training; shower program; upper extremities training to increase strength for the increased demands of wheelchair propulsion and walking with assistive devices; home evaluation; family training; and a home exercise program.

❍ Orthotic/assistive devices - May be needed for functional household ambulation and, if possible, community ambulation.

http://www.emedicine.com/neuro/topic667.htm (13 of 14)8/20/2004 5:15:44 PM eMedicine - Cauda Equina and Conus Medullaris Syndromes : Article by Segun T Dawodu, MD, FAAPMR, FAAEM, CIME

■ This entails prescribing and training in proper use of knee-ankle-foot orthoses (KAFO) with forearm crutches for support; for lower lesions, KAFOs or AFOs with canes or crutches may be needed.

■ In addition to the above, bathtub bench, transfer boards, pressure-relieving seats, and wheelchairs are devices that may be needed. The patient should be assessed for these needs prior to discharge from the acute rehabilitation setting.

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