Carpal Tunnel Syndrome

Question 1

Define Carpal Tunnel Syndrome

Answer 1

Carpal tunnel syndrome is a peripheral neuropathy caused by chronic or acute compression of the median nerve by the transverse carpal ligament/carpal tunnel. It is characterized by both sensory disturbances (pain, tingling, and numbness) and motor symptoms (weakness and clumsiness of the thumb) in the area innervated by the median nerve distal to the carpal tunnel

Question 2

Aetiology/Risk factors for CTS

Answer 2

Ultimately it is rare to find any single definite cause in a patient, and causation is very likely to be multi-factorial

• DISTAL RADIUS FRACTURE (most important risk factor)
• Manual work: prolonged, forceful, and repetitive flexion/extension of the wrist
• Rheumatoid arthritis (leading to chronic inflammation of the tendon sheath/tenosynovitis)
• Systemic Amyloidosis
• Long-term Dialysis (causes amyloidosis)
• Pregnancy
• Obesity (hypothyroidism may be a cause)
• Diabetes with peripheral polyneuropathy
• Acromegaly

Question 3

Epidemiology

Answer 3

• Females aged 40-60

Question 4

Presenting symptoms (8)

Answer 4

Characterised by GRADUAL ONSET, INTERMITTENT symptoms

• Tingling/Numbness in hand (may or may not be in median nerve distribution)
  
  • Numbness spares skin over thenar eminence as (supplied by palmar branch)
  • Radial and ulnar areas should be intact
• Night-time worsening (waking up with tingling/hand and shaking hand for relief)

Motor symptoms are present in Moderate/Severe CTS:

• Dropping items/clumsy
• Decreased strength for rotational movements (opening jam)

Question 5

Signs on physical examination

Answer 5

• Loss of fine touch sensation
• Normal reflexes
• Weakened opposition, Weakened power grip
• Thenar atrophy (only if severe)
• Clinical test:
  
  • Hand elevation test (Sensitive & Specific): The hand is held above the head of the patient for approx. two minutes. The test is considered positive if the symptoms of CTS are reproduced.
  • Phalen test: The examiner actively or passively holds the patient’s wrist in full flexion (90°). The test is positive if paresthesia occurs or worsens in the areas innervated by the median nerve within one minute. This finding is considered highly specific (approx. 85%) for the diagnosis of CTS.
  • Tinel sign: Percussion or tapping over the carpal tunnel leads to shooting pain and/or tingling in the areas innervated by the median nerve.

Question 6

Investigations for Carpal Tunnel Syndrome

Answer 6

• EMG
  
  • focal slowing of conduction velocity in the median sensory nerves across the carpal tunnel
  • decreased amplitude
• Nerve conduction studies
• Ultrasound for Space-occupying lesions