Carpal Tunnel Syndrome

Question 1

What is Carpal Tunnel Syndrome?

Answer 1

Sx + signs brought on by compression of the median nerve in the carpal tunnel.

Question 2

What structures are within the Carpal Tunnel?

Answer 2

Flexor digitorum profundus (4 tendons)
Flexor digitorum superficialis (4 tendons)
Flexor pollicis longus
Median nerve

Question 3

Describe the aetiology of Carpal Tunnel Syndrome

Answer 3

Sx are caused by compression of the median nerve as it runs through the carpal tunnel
Usually IDIOPATHIC

Question 4

List 5 conditions that may cause secondary Carpal Tunnel Syndrome

Answer 4

Tenosynovitis (e.g. RA)
Infiltrative diseases of the canal/ increased soft tissue (e.g. amyloidosis, acromegaly)
Bone involvement in the wrist (e.g. osteoarthritis, fracture)
Fluid retention states (e.g. pregnancy, nephrotic syndrome)
Other (e.g. obesity, menopause, diabetes)

Question 5

List 9 risk factors for Carpal Tunnel Syndrome

Answer 5

Variations of anatomy of the carpal tunnel 
> 30 yrs 
High BMI 
Pregnancy 
Occupations with repetitive wrist movements 
Fractured wrist/ carpal bones (lunate) 
RA
DM 
Dialysis

Question 6

Describe the epidemiology of Carpal Tunnel Syndrome

Answer 6

Prevalence: 2.7%

Lifetime risk of 10%

Question 7

List 3 symptoms of Carpal Tunnel Syndrome

Answer 7

Tingling + pain in the hand + fingers
Weakness + clumsiness of the hand (difficulty in fine motor tasks)
Waking up at night-time with paraesthesias /pain in hand/ wrist, + shaking the hand to relieve Sx

Question 8

Describe nature of symptoms in Carpal Tunnel Syndrome

Answer 8

Sx are intermittent + gradual onset

Question 9

List 6 signs of Carpal Tunnel Syndrome

Answer 9

Sensory impairment in the median nerve distribution
Weakness + wasting of thenar eminence
Tinel’s Sign: tapping the carpal tunnel causes Sx
Phalen’s Test: flexion of the wrist for 1 min may cause Sx
Signs of underlying cause (e.g. acromegaly, hypothyroidism)
NORMAL REFLEXES

Question 10

What is the diagnostic test used for Carpal Tunnel Syndrome?

Answer 10

EMG

Focal slowing of conduction velocity (prolongation of AP) in the median sensory nerve across the carpal tunnel

Question 11

What other investigations may be used to look for underlying causes in Carpal Tunnel Syndrome?

Answer 11

TFTs

ESR

Question 12

What mnemonic is used to remember causes of CTS?

Answer 12

MEDIAN TRAPS
Myxoedema (hypothyroidism)
Enforced flexion 
Diabetic neuropathy
Idiopathic
Acromegaly
Neoplasms e.g. myeloma
Tumours (benign) e.g. Lipoma
RA
Amyloidosis
Pregnancy/ premenstrual oedema
Sarcoidosis