sign in sign up
<<
Home , Formication, Paresthesia

Easy Approach to Numbness and Tingling

Juan J. Figueroa, MD Medical College of Wisconsin

• Nothing to disclose

1 Numbness and Tingling

• Symptoms beneath or on the skin described in a variety of colorful ways: • Document patient’s own words • Numbness: – Falling asleep sensation – Underfoot foreign body when walking (roughness, sand, wool, eggshells, rolls of skin, crumpled socks, pebbles, wrapped/tight, walking on pillows) • Tingling: – Prickling – Pins and needles – Buzzing – Creeping – Crawling ()

Mechanisms

• Spontaneous ectopic discharges in sensory units – Hyperexcitable sensory pathways – Anomalous discharge patterns – Unfamiliar combination of basic sensations ‐> unnatural sensations of numbness and tingling • Focal compression – Physical maneuvers impinging on hyperexcitable sensory : (Tinel, Lasegue, and Spurling) • – Increases axonal excitability – Impaired Na/K pump ‐> Increased extracellular K ‐> spontaneous ectopic discharges > • – High pH‐induced activation axonal sodium channels

2 Terminology

• Negative sensory symptoms – Loss of feeling ( damage) • Positive sensory symptoms – Paresthesias: numbness and tingling (Disturbance of skin sensation; ICD‐9 = 782.0, ICD‐10 = R20.9) – : burning, lancinating or shooting (often worse at night) • Rapidly progressive – inflammatory process • Asymmetric ‐ vasculitis – Allodynia: pain to non‐painful stimuli – : increased sensitivity to painful stimuli

Paresthesia: Unpleasant Sensation

• Patients’ fears: – “Do I have ?” – “Is this a mini‐stroke?” – “Do I have neuropathy” • We need to establish: neurologic vs. non‐neurologic • Non‐neurologic – Poor circulation – – Conversion • Work‐up – If neurologic: central versus peripheral • When to refer to a neuromuscular neurologist?

3 Step‐by‐Step Approach (Example: ) • What? – Numbness/tingling () • Where? – Paresthesia of he hand • When? – Paresthesia of the hand that is chronic and intermittent • Setting? – Paresthesia of the hand that is chronic and intermittent triggered by repetitive hand motion • Axon or myelin? – Paresthesia of the hand that is chronic and intermittent triggered by repetitive hand motion associated with atrophy of thenar eminence

Distribution (Where?)

• Peripheral Nervous System – Generalized bilateral – Localized to one side the face – Chin (numb chin syndrome) – Localized to one limb (signs: Phalen, Tinel, Lasegue, Spurling) • (Brain or spinal cord) – Generalized unilateral involvement of face or extremity – Trunk involvement (Lhermitte’s sign) • Non‐neurologic – Whole body (from top to bottom) – Perioral (hyperventilation) – Lower limbs when standing (better with leg elevation or compression stocking) – Lower limbs with changing distributions that is intermittent and unexplained (no deficits) in patient with widespread musculoskeletal tenderness

4 Temporal Profile (Etiology?)

• Acute – Sudden onset (vasculitic neuropathy or stroke/trauma) – Evolution over several seconds (seizure) – Evolution over minutes (, ) – Evolution over hours to days (GBS) • Chronic – Insidious onset (distal ) – Static (old ) – Progressive (CIDP) – Relapsing‐remitting (CIDP)

Setting (Etiology?)

Medications that cause neuropathy • Anti‐infectious – – – Nitrofurantoin • Chemotherapy – Platinum‐based drugs (e.g. cisplatinum) – Taxanes (e.g. ) – Thalidomide – Vincristine • Antirheumatic – Colchicine • Cardiovascular – Amiodarone • Other – Pyridoxine

5 Approach for Generalized Symptoms (Chronic Axonal )

(Asymmetric/painful)

Maeurmann ML & Burns TM. Seminars in Neurology. 2008

Approach for Localized Symptoms (More Restricted Nerve Problem) • Mononeuropathy – One limb in a nerve distribution: • Carpal tunnel syndrome • at the elbow • Peroneal neuropathy • Lateral femoral cutaneous neuropathy – Face only • Trigeminal neuropathy • – On limb restricted to a dermatome and myotome • Plexopathy – One limb but more extensive

6 Electrodiagnostic Testing (Large nerve fibers) • Confirms: – The what (sensory, motor, both?) – The where (distal vs. proximal, symmetric vs. asymmetric, cell body vs. axon) – The when (acute vs. chronic, active vs. inactive) – And quantifies severity • Characterizes neuropathy further as: – Axonal (e.g. metabolic, toxic, idiopathic, CMT2) – Demyelinating (e.g. GBS, CIDP, CMT1)

Epidermal Nerve Fiber Density (Small nerve fibers) • If NCS/EMG is unrevealing (no large fiber involvement) • Is this a predominantly small fiber neuropathy? • Skin punch biopsy for cutaneous nerve evaluation through nerve fiber analysis

7 Referral for Tests to Confirm Neuropathy

• FMLH Neurophysiology Lab – NCS/EMG for large fiber neuropathy

• FMLH Neuroscience Clinic – Punch skin biopsy for small fiber neuropathy

Labs

Standard • Alcohol abuse • • Systemic disease – Nutritional (B12/MMA, thiamine) – Endocrinologic (TSH) – Rheumatologic (ANA, RF, SSa/SSb) – Plasma cell dyscrasia (SPEP/IF) If additional risk factors • Infectious – – HIV • Malignancy – Paraneoplastic panel

8 Idiopathic/Cryptogenic Neuropathy

• Criteria – Predominantly sensory – EMG/NCS: • Mild to moderate • Axonal – Extensive labs negative (diabetes, malignancy and systemic disease) • Very common • Lingering uncertainty about cause and uncontrolled pain – Can be frustrating for both patient and physician • Persistent and fluctuating pain over years – Early referral to a Advance Pain Clinic for longitudinal pain care

Neuromuscular Consult Referral for Confirmed Neuropathy

• Unexplained • Relatively severe • Demyelinating • Sudden onset • Progressive • Associated motor deficits • Concerned for inherited, rheumatologic, paraproteinemic or paraneoplastic neuropathy • Question of nerve biopsy

9 Simultaneous Referral to Other Specialists • Rheumatology – If positive rheumatologic markers • Hematology – If positive paraproteinemia • Advanced Pain Clinic – If painful

10