Overview
Definition
An entrapment neuropathy caused by compression of the median nerve as it travels through the carpal tunnel in the wrist.
Epidemiology
The most common compressive neuropathy. More common in women, typists, and pregnant patients.
Etiology & Risk Factors
- Any condition that reduces the size of the carpal tunnel or increases the volume of its contents: Repetitive strain, obesity, pregnancy (fluid retention), Rheumatoid arthritis, Hypothyroidism, Diabetes.
Clinical Symptoms
- Pain, numbness, and tingling in the median nerve distribution (thumb, index, middle, and radial half of the ring finger)
- Symptoms are often worse at night (waking the patient up)
- Aching pain radiating up the forearm
- Weakness in grip and dropping objects
Clinical Approach
Diagnosis
- Tinel's Sign: Tapping the median nerve at the wrist elicits a tingling sensation
- Phalen's Test: Flexing the wrists together for 60 seconds reproduces symptoms
- Nerve Conduction Studies (NCS) / EMG: Gold standard for confirming and grading severity
Management
- Conservative: Nighttime wrist splinting (neutral position), ergonomic adjustments, NSAIDs
- Injections: Corticosteroid injection into the carpal tunnel
- Surgical: Carpal Tunnel Release (severing the transverse carpal ligament) for severe or refractory cases
Complications
- Permanent median nerve damage
- Thenar eminence atrophy (wasting of the muscle at the base of the thumb - a sign of advanced/chronic disease)