Carpal Tunnel

Question 1

Define:

Answer 1

• Carpal tunnel syndrome refers to the symptom complex brought on by compression of the median nerve in the carpal tunnel

Question 2

Aetiology/risk factors:

Answer 2

• Symptoms are caused by compression of the median nerve as it runs through the carpal tunnel
• Usually IDIOPATHIC
• May be SECONDARY to:
o Tenosynovitis (e.g. in rheumatoid arthritis)
o Infiltrative diseases of the canal/increased soft tissue (e.g. amyloidosis, acromegaly)
o Bone involvement in the wrist (e.g. osteoarthritis, fracture)
o Fluid retention states (e.g. pregnancy, nephrotic syndrome)
o Other (e.g. obesity, menopause, diabetes)

Question 3

Epidemiology:

Answer 3

• Prevalence: 2.7%

* Lifetime risk of 10%

Question 4

Symptoms:

Answer 4

• Tingling and pain in the hand and fingers

* Weakness and clumsiness of the hand

Question 5

Signs:

Answer 5

• Sensory impairment in the median nerve distribution
• Weakness and wasting of thenar eminence (image)
• Tinel’s Sign - tapping the carpal tunnel causes symptoms
• Phalen’s Test - flexion of the wrist for 1 min may cause symptoms
• Look out for signs of the underlying cause (e.g. acromegaly, hypothyroidism)

Question 6

Investigations:

Answer 6

• Bloods
o TFTs
o ESR
• Neurophysiology helps confirm lesion’s site and severity
• Nerve Conduction Study (not usually necessary)
o Shows impaired median nerve conduction across the carpal tunnel