Introduction

Carpal tunnel syndrome is caused by compression of median nerve in the carpal tunnel.

Epidemiology

  • Incidence: 200.00 cases per 100,000 person-years
  • Peak incidence: 50-60 years
  • Sex ratio: more common in females 5:1
Condition Relative
incidence
Cervical spondylosis1.50
Carpal tunnel syndrome1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Aetiology

Causes
  • idiopathic
  • pregnancy
  • oedema e.g. heart failure
  • lunate fracture
  • rheumatoid arthritis

Clinical features

History
  • pain/pins and needles in thumb, index, middle finger
  • unusually the symptoms may 'ascend' proximally
  • patient shakes his hand to obtain relief, classically at night

Examination
  • weakness of thumb abduction (abductor pollicis brevis)
  • wasting of thenar eminence (NOT hypothenar)
  • Tinel's sign: tapping causes paraesthesia
  • Phalen's sign: flexion of wrist causes symptoms

Investigations

Electrophysiology
  • motor + sensory: prolongation of the action potential

Management

Treatment
  • corticosteroid injection
  • wrist splints at night
  • surgical decompression (flexor retinaculum division)