Carpal Tunnel Syndrome

Question 1

Define

Answer 1

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

Median nerve and 9 tendons compete for space in the wrist Compression is common

→Carpel tunnel is formed by the flexor retinaculum superiorly and the carpal bones inferiorly

Question 2

Causes

Answer 2

43% idiopathic

May be 2ndary to

• Tenosynovitis → Overuse, RhA, other inflammatory rheumatic disease
• Infiltrative diseases of the canal/↑ soft tissue → Amyloidosis, myeloma myxoedema, acromegaly
• Bone involvement in the wrist → Osteoarthritis, fracture, tumour Fluid retention states →Pregnancy, nephrotic syndrome
• Other → Obesity, menopause, diabetes, end-stage renal disease

Famous median traps:

Myxoedema; Enforced flexion (e.g. in a Colles’ splint); Diabetic neuropathy; Idiopathic; Acromegaly; Neoplasms (e.g. myeloma); benign Tumours (lipomas, ganglia); Rheumatoid arthritis; Amyloidosis; Pregnancy/premenstrual oedema; Sarcoidosis

Question 3

Epidemiology

Answer 3

most common in women who have narrower wrists but similar sized tendons to men

• Overall prevalence 2.7%
• Incidence in adults 0.1% per year
• Lifetime risk 10%

Question 4

Risk factors

Answer 4

Conditions that cause arm pain/swelling in joints and soft tissues or reduce blood flow to hand (e.g. obesity, RhA, DM, hypothyroidism, MS)

• FEMALE
• Hand and wrist movements and activates requiring

awkward repeated motions

• Smoking
• Broken wrist bones, dislocated bones
• Tumours or ganglions
• Wear and tear of tissues in wrist due to aging

Question 5

Symptoms

Answer 5

• Aching pain in hand or arm (especially at night)
• Tingling/paraesthesia in the thumb, index and middle fingers

Relived by ‘wake and shake’ Weakness and clumsiness of hand

• ±Sensory loss of abductor pollicis brevis

Question 6

Signs

Answer 6

Sensory impairment in the median nerve distribution (first 31⁄2 fingers)

• Weakness and wasting of the thenar eminence
• ±Impairment of light touch, 2-point discrimination and
• sweating
• Signs of the underlying cause, e.g. hypothyroidism or acromegaly

Tinel’s sign → Tapping carpal tunnel triggers symptoms

Phalen’s test → Maximal flexion of the wrist for 1min may cause symptoms.

Question 7

Investigations

Answer 7

Bloods

• TFTs
• ESR

Nerve Conduction Study (not usually necessary)

• Shows impaired median nerve conduction across the carpal tunnel