Carpal tunnel syndrome is compression of the median nerve as it passes through a tight tunnel at the wrist. It is the most common nerve entrapment and is linked to repetitive hand use, pregnancy, diabetes, hypothyroidism and obesity.
Key symptoms
- Numbness and tingling in the thumb, index, middle and half of the ring finger
- Symptoms that wake the patient at night, eased by shaking the hand
- Clumsiness and dropping objects
- Aching that may spread to the forearm
What you find on exam
- Sensory loss in the median nerve area, sparing the base of the palm
- Tinel sign at the wrist and Phalen test
- Carpal compression test
- Weak thumb abduction and thenar muscle wasting in advanced cases
Tests
- Diagnosis is often clinical
- Nerve conduction studies and electromyography to confirm and grade severity
- Ultrasound of the median nerve
- Glucose, HbA1c and thyroid tests when a cause is suspected
Treatment basics
- Neutral wrist splint at night
- Activity changes and ergonomic adjustments
- Corticosteroid injection into the carpal tunnel
- Surgical carpal tunnel release for severe or persistent cases or thenar wasting
Red flags
- Thenar muscle wasting or constant numbness
- Sudden symptoms after a wrist fracture or injury (acute carpal tunnel)
- Weakness or numbness beyond the median nerve area
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.