TremorsTTremorsTTremorsemorss By Laura M. Struble, PhD, GNP-BC tremor is a common, abnormal, involuntary move- sleep.4 Tremors can be transient and vanish over time or ment of muscles that may be noted during a rou- chronic and progressive. Patients with a tremor may have A tine physical exam. It is defi ned as an unintentional minor functional consequences or extreme functional dis- rhythmical oscillatory movement of a body part.1 Tremors abilities. Tremors can be embarrassing, and some patients may be a sign of an underlying disease or simply an exag- are afraid to be seen in public. It is important for the NP to gerated physiologic tremor observed in healthy people. assess tremor symptoms quickly and accurately to maximize Identifying the type of tremor is necessary to determine therapy and avoid unnecessary referrals. underlying neurologic disorders. The gold standard for diagnosing tremors is still history and physical exam.1 ■ Classifi cation of tremor Tremors are broadly categorized as hyperkinetic. They have ■ What is a tremor? different activation conditions, frequencies, and amplitudes. Tremors are commonly associated with movement disorders To be defi ned as a tremor, a movement must be rhythmic that have multiple etiologies and an extensive list of differen- and have a pattern. The widely accepted classifi cation divides tial diagnoses. Most tremors are associated with neurologic tremors into two types: rest and action.1 conditions related to certain parts of the brain (such as basal motor nuclei, inferior olivary nucleus, and cerebellum) that Rest tremor control muscles throughout the body or a specifi c body part Rest tremor occurs in a body part that is relaxed and fully such as the hands.2 Pathologic tremors include brain injury supported against gravity (for example, hands resting in essential tremor, multiple sclerosis, Parkinson disease (PD), the lap). The rate of this type of tremor is usually between stroke, and neurodegenerative diseases that damage the 3 and 6 Hz/cycle/second.5 If the rest tremor is mild or inter- brainstem or cerebellum. Metabolic disturbances that affect mittent, it can be brought out or intensifi ed by having the the brain and may produce tremors include drugs, alcohol, patient concentrate on a different task, such as opening and mercury poisoning, hyperthyroidism, hypoglycemia, or closing the contralateral hand or performing arithmetic.4 vitamin deficiencies (magnesium, thiamin). Insect bites Rest tremors are commonly observed in PD and account from a black widow spider or red back spider may produce for about 75% of all cases of rest tremors.5 Rest tremors are tremors. Finally, genetics may play a role in the development seldom seen in other conditions.6 of tremors.3 Action tremor ■ Characteristics of tremor An action tremor is produced by voluntary muscle contrac- Tremors can happen at any age, but their likelihood increases tion and is further classifi ed as: postural, kinetic, isometric, with age. They can occur in the hands, head, jaw, tongue, or task-specifi c. palate, vocal cords, trunk, or legs. Tremor may occur in one 1. Postural tremor is produced when the affected body part part of the body and progress to others, or may be seen in maintains its position against gravity (such as extending multiple extremities all at once. Diagnosis of the underlying arms in front of the body). cause becomes diffi cult when there is more than one type 2. Kinetic tremor is produced during a voluntary move- of tremor present. The majority of involuntary tremors ment and can be subdivided into simple kinetic tremor increase during emotional stress, strong emotions, and/or or intention tremor. physical fatigue. However, if a person is calm and relaxed, a. Simple kinetic tremor occurs with movement of ex- most tremors are dampened and usually disappear during tremities (such as fl exion-extension of the wrist). Karapelou © Illustration by John W. 18 The Nurse Practitioner • Vol. 35, No. 6 www.tnpj.com Copyright © 2010 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 2.5 CONTACT HOURS Learning to stop the shakes www.tnpj.com The Nurse Practitioner • June 2010 19 Copyright © 2010 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Tremors: Learning to stop the shakes b. Intention tremor is produced with visually guided toms of ET are largely symmetrical, occurring primarily in movements directed toward a specifi c target with sig- the upper limbs (95%), and specifi cally in the hands. ET nifi cant amplitude fl uctuation when approaching the symptoms may also be noted in the head (35%), lower limbs target (when performing point-to-point movements, (20%), voice (12%), and trunk (5%).18 The frequency of the such as fi nger-nose-fi nger).7 Intention tremors are tremor ranges from 4 to 12 Hz and is usually symmetrical. commonly seen with cerebellar lesions.4 The amplitude of ET tremors increases with fatigue, anxiety, 3. Isometric tremor occurs when there are voluntary mus- stress, certain medications, and/or cold temperatures. cle contractions without movement (such as pushing Pharmacologic treatment options do not cure the trem- against a wall). or, but may improve function and reduce embarrassment. 4. Task-specifi c tremor is rare and only occurs when per- The fi rst-line therapies are propranolol and primidone. If forming a specifi c task such as writing, playing music, the tremor is not reduced or the adverse reaction profi le is or speaking.4,7,8 too high, second-line therapies include gabapentin, alpra- zolam, nimodipine, and theophylline.12,15 Propranolol is the ■ Common tremor syndromes only drug with labeled-use for symptomatic treatment of Tremors are classifi ed according to clinical features (see essential tremor; other drugs listed are off-label use. Moder- Classifi cation and description of tremor syndromes).6,8,9 ate alcohol consumption can cause a transient decrease or alleviation of an ET; however, there may be a rebound effect Physiologic tremor once the alcohol has worn off. The use of alcohol to manage Physiologic tremor is an action tremor present in everyone. ET is not recommended but if the patient indicates that it This benign tremor is usually postural and does not interfere helps this information supports the diagnosis of ET.9,18,19 with activities of daily living. It is diffi cult to see with the naked eye and described as a high-frequency, low-amplitude Tremor in children tremor. Increased or enhanced physiologic tremor is de- Tremor syndromes appear throughout childhood from neo- scribed as an easily visible, high-frequency tremor with no nate through adolescence. Movement disorders are some- evidence of an underlying neurologic disease.1,11 Emotional times missed in the very young if they are less apparent or stress, fear, or anxiety can exacerbate this tremor. Other pre- slow progressing. It may not be until children show signs of cipitating factors include muscle fatigue, lack of sleep, and impairment in school or recreational activities that parents consuming large amounts of caffeinated drinks. Medical consult the primary care provider. As with adults, ET is the conditions that, if corrected, would reverse exacerbated physi- most common form of tremor in children and usually seen ologic tremor include thyrotoxicosis, hypoglycemia, certain in the teenage years. Infantile tremors resulting from vitamin drugs (such as some anticonvulsants, antidepressants, and B12 defi ciency and Wilson disease between the ages of 6 and 20 neuroleptics),14 and withdrawal from benzodiazepines and years should always be ruled out. Other childhood tremors are alcohol.6,8,12 most likely due to underlying metabolic and endocrine disor- ders, heterodegenerative disorders, or are drug-induced.10,11 Essential tremor ET, formally known as benign ET, is the most common form Drug-induced tremors of action tremor. It is the most common movement disorder Tremor is a frequent adverse reaction of medications related in the world and is diagnosed primarily by clinical presenta- to drug toxicity and withdrawal from certain drugs.8 Rest tion.7,8,12,15 It is almost 20 times more prevalent than PD.16 tremor, action/postural tremor, and intention tremor can be Although ET is not life-threatening, the condition does drug-induced. (see Drugs that can cause rest, action/postural have devastating consequences. Typically, ET is a postural and intention tremors). Most drug-induced tremors are or kinetic action tremor mainly affecting the hands. Patients symmetrical except for parkinsonism tremor. To determine often complain of diffi culty writing, drawing, drinking from whether a tremor is drug-induced, NPs should rule out other a cup, or using a computer. Usually, no other neurologic medical etiologies. A temporal relationship to the start of symptoms are present.1 ET has an insidious onset and pro- a drug should be investigated to determine whether there gresses over time. The condition affects males and females is a dose-response relationship. Finally, the tremor course equally and occurs most often in adolescents and adults should not be progressive in drug-induced tremors.13 in their 50s or 60s. Almost half of ET cases are considered familial from an autosomal dominant gene.17 ET usually Parkinsonism tremor starts in the arms with the fl exion-extension of the wrists or Parkinsonism tremor is the most common form of rest trem- abduction-adduction movement of the fi ngers.4 The symp- or. Parkinsonism is a group of movement disorders that have 20 The Nurse