Carpal Tunnel Syndrome (CTS)
Carpal tunnel syndrome (CTS) is the commonest entrapment neuropathy. It results from compression of the median nerve within the carpal tunnel at the volar wrist and produces sensory disturbance, and in advanced cases motor dysfunction, in the median nerve distribution.
In emergency care the priorities are recognising the typical presentation, excluding acute or reversible causes, providing initial symptomatic treatment, and arranging timely follow‑up or urgent specialist referral where indicated (NICE NG127; MOD synopsis).
Epidemiology
- Incidence approximately 2.5 per 1,000 population per year.
- Marked female predominance (female:male commonly 3:1 to 10:1).
- Peak incidence in middle age; fewer than 10% of cases occur before age 30.
- Often bilateral; a strictly unilateral presentation should prompt consideration of a local structural cause (trauma, mass).
Anatomy and pathophysiology
The carpal tunnel is an osteo‑fibrous canal at the volar wrist bounded dorsally by the carpal bones and volarly by the transverse carpal (flexor retinaculum) ligament. It contains the median nerve, flexor tendons and their synovial sheaths.
Compression arises from either reduced tunnel volume or increased content volume:
- Reduced tunnel volume: fracture malunion, carpal subluxation, synovial hypertrophy from inflammatory arthropathy.
- Increased content volume: tenosynovitis, pregnancy‑related oedema, myxoedema.
- Systemic conditions such as diabetes and pre‑existing peripheral neuropathy increase nerve vulnerability.