What is the appropriate workup for a patient presenting with hand numbness?

Workup for Hand Numbness

Start with plain radiographs (three standard views: PA, lateral, and oblique) as the initial imaging study, followed by targeted clinical examination including dermatomal sensory testing, Tinel's sign at the wrist, and Phalen's maneuver to differentiate between carpal tunnel syndrome, cervical radiculopathy, and other nerve compression syndromes. 1, 2

Initial Clinical Assessment

History and Symptom Distribution

• Document the precise anatomic distribution of numbness: Symptoms involving the thumb, index, middle, and radial half of the ring finger (but NOT the little finger or dorsum of hand) strongly suggest carpal tunnel syndrome 3
• Assess timing: Nocturnal symptoms with pain, tingling, and numbness are classic for carpal tunnel syndrome 4, 5
• Screen for red flags:
  • Sudden onset with vascular risk factors requires urgent stroke evaluation 2
  • Bilateral hand numbness with lower extremity symptoms suggests cervical myelopathy requiring urgent neurosurgical consultation 2
  • Unilateral presentations should NOT be assumed to represent symmetric neuropathy patterns (diabetic or chemotherapy-induced) 2

Physical Examination Maneuvers

• Tinel's sign at the wrist: Percussion over the median nerve; positive predictive value of 0.55 for carpal tunnel syndrome 6
• Phalen's maneuver: Wrist hyperflexion reproducing symptoms 4, 7
• Durkan test: Firm digital pressure across the carpal tunnel (64% sensitive, 83% specific) 5
• Dermatomal sensory testing: Pinprick, light touch, and two-point discrimination in C5-T1 distribution to diagnose cervical radiculopathy 2
• The combination of positive Tinel's sign AND classic symptom distribution has a positive predictive value of 0.71 6

Diagnostic Algorithm

Step 1: Initial Imaging

• Obtain plain radiographs first (three standard views) even for suspected soft tissue pathology to exclude underlying bony abnormalities 1, 8
• This establishes baseline assessment and rules out structural causes 1

Step 2: Electrodiagnostic Testing

• Nerve conduction studies are the gold standard (>80% sensitive, 95% specific for carpal tunnel syndrome) 5
• Indications for electrodiagnostic testing:
  • Symptoms persisting beyond 4-6 weeks despite conservative measures 2
  • Suspected proximal compression or other compressive neuropathies 5
  • Need to differentiate between carpal tunnel syndrome, cubital tunnel syndrome, cervical radiculopathy, or thoracic outlet syndrome 7
• Low-risk patients who may NOT need nerve conduction studies: Patients under 40 years of age with "possible" or "unlikely" symptom distribution patterns 6

Step 3: Advanced Imaging (When Indicated)

• Ultrasound: Use when initial radiographs are negative/equivocal and soft tissue pathology is suspected 8
• MRI without IV contrast: Reserved for inconclusive ultrasound findings, persistent symptoms, or suspected cervical radiculopathy requiring detailed evaluation 1, 2
• Arteriography (from aortic arch to palmar arch): Only for patients with dialysis access presenting with hand ischemia/numbness to evaluate for steal syndrome 1

Differential Diagnosis Framework

Median Nerve Distribution (Thumb, Index, Middle, Radial Ring Finger)

• Carpal tunnel syndrome: Most common peripheral neuropathy, affects middle-aged women, associated with obesity, diabetes, keyboard use, vibrating tools 4, 5
• Cervical radiculopathy: Requires dermatomal testing; may need selective nerve root blocks if conservative management fails (75% improvement rate) 2

Ulnar Nerve Distribution (Little Finger, Ulnar Ring Finger)

• Cubital tunnel syndrome (compression above elbow) or ulnar tunnel syndrome (compression at wrist) 7
• Differentiate from cervical radiculopathy or thoracic outlet syndrome using electromyography and radiography 7

Radial Nerve Distribution

• Radial tunnel syndrome: May accompany lateral epicondylitis; radial nerve block helps differentiate 7

Vascular Causes

• Dialysis-associated steal syndrome (DASS): Hand numbness in dialysis patients with AV access; requires arteriography for diagnosis 1

Common Pitfalls to Avoid

• Do NOT skip initial radiographs even for obviously soft tissue presentations 1, 8
• Do NOT order MRI as first-line imaging—not cost-effective or guideline-supported 1, 8
• Do NOT assume bilateral symmetric neuropathy patterns in unilateral presentations 2
• Do NOT rely on physical examination alone—no single test is diagnostic; combination of findings is required 4, 6
• Do NOT attribute to occupation without excluding intrinsic factors like obesity, diabetes, hypothyroidism, rheumatoid arthritis 4, 7

When to Refer

• Neurology: Suspected focal dystonia, progressive weakness, motor neuron disease signs, or abnormal nerve conduction studies 2, 9
• Hand surgery: Moderate-to-severe carpal tunnel syndrome unresponsive to conservative treatment (splinting, steroid injection) 4, 5
• Neurosurgery (urgent): Bilateral hand numbness with lower extremity symptoms suggesting myelopathy 2
• Vascular surgery: Dialysis patients with hand ischemia/numbness 1