What are the possible causes of hand numbness and how should it be evaluated and managed?

Hand Numbness: Diagnostic Approach and Management

Immediate Urgent Evaluation Required

Bilateral hand numbness demands urgent MRI of the entire cervical spine without and with contrast to exclude cervical myelopathy, particularly if accompanied by any lower extremity symptoms, gait disturbance, or burning dysesthesias in the forearms. 1, 2

• Central cord syndrome presents with greater upper extremity weakness than lower extremity involvement, with bilateral hand numbness and burning forearm dysesthesias 1, 2
• Check for wide-based gait with sensory ataxia, which indicates proprioceptive loss from cord involvement 1
• Examine for upper motor neuron signs including hyperreflexia, clonus, and extensor plantar responses 2
• If cord pathology is confirmed, immediate neurosurgical consultation is required 1, 2

Rapidly progressive bilateral weakness with paresthesias requires urgent evaluation for Guillain-Barré Syndrome (GBS), as approximately 20% develop respiratory failure requiring mechanical ventilation. 2

• Red flags include areflexia/hyporeflexia, declining vital capacity, and dysautonomia 2
• Two-thirds report preceding infection within 6 weeks (Campylobacter jejuni, CMV, Hepatitis E, Mycoplasma, EBV, Zika) 2
• Urgent MRI of entire spine, CSF analysis (increased protein with normal cell count supports diagnosis), and respiratory monitoring are mandatory 2
• If confirmed, initiate IVIG 2 g/kg over 5 days or plasmapheresis immediately 2

Most Common Cause: Carpal Tunnel Syndrome

For unilateral or bilateral hand numbness affecting the thumb, index, middle, and radial ring fingers, carpal tunnel syndrome is the most likely diagnosis and should be evaluated first. 3, 4

• Perform the Durkan maneuver (firm digital pressure across carpal tunnel to reproduce symptoms): 64% sensitive and 83% specific 3
• Symptoms typically worsen at night and with repetitive hand use 3, 5
• More common in women, obesity, diabetes, and occupations involving keyboards, computer mouse, heavy machinery, or vibrating tools 3
• Electrodiagnostic testing is >80% sensitive and 95% specific, but only order if diagnosis is uncertain or proximal compression is suspected 3, 4

Initial treatment consists of volar splinting and corticosteroid injection, which temporarily relieve symptoms in most patients. 3, 4

• Patients who fail conservative therapy should undergo open or endoscopic carpal tunnel release for definitive treatment 3

Systematic Metabolic Workup

Order first-tier laboratory studies immediately: TSH and free thyroxine, fasting glucose and HbA1c, vitamin B12, complete blood count, complete metabolic panel, and serum calcium. 1, 6

Hypothyroidism

• Causes peripheral neuropathy through metabolic disruption, presenting with stocking-glove distribution numbness and tingling 1
• Physical examination reveals delayed ankle reflexes, periorbital puffiness, coarse skin, cold skin, and slow movement 1
• Optimize thyroid hormone replacement to achieve normal TSH and free thyroxine levels 1

Diabetic Peripheral Neuropathy

• Presents with symmetric stocking-glove distribution, typically starting distally in feet before hands 7, 6, 2
• Test temperature/pinprick sensation and vibration with 128-Hz tuning fork 2
• Assess annually with 10-g monofilament for protective sensation 7
• Optimize glucose control to prevent progression, though this does not reverse neuronal loss 7, 2

Vitamin B12 Deficiency

• Causes peripheral neuropathy with numbness and tingling in hands and feet 1
• Check serum B12 level immediately 1

Uremic Neuropathy

• Check creatinine, eGFR, and urinalysis 2

Additional Differential Diagnoses

Ulnar Nerve Compression

• Decreased sensation of little finger and ulnar aspect of ring finger, with intrinsic muscle weakness 4
• May occur at cubital tunnel (above elbow) or ulnar tunnel (at wrist) 4
• Differentiate from cervical radiculopathy or thoracic outlet syndrome with electromyography if diagnosis unclear 4

Chemotherapy-Induced Peripheral Neuropathy (CIPN)

• Occurs in 30-40% of patients after taxane-based or platinum-based chemotherapy 7, 2
• Primarily sensory with numbness, tingling, and pain in stocking-glove distribution 7
• Paclitaxel symptoms are more prominent in lower extremities; oxaliplatin symptoms more severe in upper extremities during treatment 7
• Oxaliplatin neuropathy worsens for 2-3 months after cessation (coasting phenomenon) before improving 7

Hepatitis C-Related Neuropathy

• Occurs in up to 50% of HCV-infected patients 2
• Most common symptoms include sensory loss, paresthesias, numbness, cramps, burning feet, and tingling 2
• Check hepatitis C serology if risk factors present 6

Pharmacologic Treatment for Neuropathic Symptoms

Duloxetine 60 mg once daily is the first-line pharmacologic treatment for neuropathic pain associated with peripheral neuropathy. 1, 6, 2

• Start duloxetine 30 mg daily for one week, then increase to 60 mg daily 1
• Alternative medications include pregabalin, gabapentin, and tricyclic antidepressants 2
• Physical activity should be offered for neuropathy symptoms 1, 2
• Acetaminophen, NSAIDs, and acupuncture can be offered for associated pain 1, 2

Critical Pitfalls to Avoid

Do not assume peripheral neuropathy without excluding cervical myelopathy—bilateral hand involvement with any lower extremity symptoms requires urgent spinal imaging. 1, 2

• Cervical cord lesions at C5-C7 level affect both upper extremities and descending motor tracts 2

Do not order routine electrodiagnostic studies for classic distal symmetric neuropathy, as clinical examination is sufficient when symptoms are symmetric and length-dependent. 7, 1

• Reserve EMG for atypical presentations, suspected proximal compression, or when diagnosis remains uncertain after initial workup 7, 3, 4

Review all medications, particularly NSAIDs used for arthritis management, which can contribute to neuropathy. 1

For patients with diabetes, perform complete neurologic evaluation at diagnosis of type 2 diabetes and at least annually thereafter, including temperature sensation, pinprick sensation, vibration perception, pressure sensation, and ankle reflexes. 2