Carpal Tunnel Syndrome Flashcards
What is carpal tunnel syndrome?
Entrapment of the median nerve at the wrist
What causes carpal tunnel syndrome?
Peripheral neuropathy due to acute or chronic compression of the median nerve by the transverse carpal ligament
= also known as median neuropathy
What is the most common cause of carpal tunnel syndrome?
Idiopathic (no clear cause), pregnancy
Which conditions can secondary cause carpal tunnel syndrome?
(1) Rheumatoid arthritis - before 50
(2) Acromegaly - after 50
(3) Conditions causing fluid retention
What is the difference in carpal tunnel syndrome during pregnancy?
Symptoms often subside after birth
Which group is more affected by carpal tunnel syndrome?
Women affected 8x more than men
What causes bilateral carpal tunnel syndrome?
Repetitive stress with symptoms worse at night
What is the cause of compression in the carpal tunnel?
(1) Inflammation of nearby tendons
(2) causes oedema (swelling)
(3) which compresses the median nerve
What structures pass through the carpal tunnel?
Median nerve
9 flexor tendons:
4 x FDS (flexor digitorum superficialis)
4 x FDP (flexor digitorum profundus)
1 x FPL (flexor pollicis longus)
What are the main symptoms of carpal tunnel syndrome?
(1) Paraesthesia in median-nerve innervated digits
(thumb and radial 3½ fingers).
(2) Tingling in the first three digits
(3) Loss of sensation/weakness in the thumb
(4) Relieved by shaking the hand.
(5) Palmar sensation usually spared
(6) Pain and pins and needles in the thumb, index, and middle fingers
What tests reproduce carpal tunnel syndrome symptoms?
Tinel’s test
(tapping over the median nerve)
Phalen’s test
(wrist hyper-flexion for 60 seconds)
What are common signs of carpal tunnel syndrome?
(1) Muscle wasting (especially of the thenar eminence) in chronic cases.
(2) Loss of sensation in the area innervated by the median nerve
(3) Decreased grip strength
What is a common questionnaire used to assess for carpal tunnel syndrome?
Kamath & Stothard questionnaire
What is the gold standard test for diagnosing carpal tunnel syndrome?
Nerve conduction studies
Slowing of conduction across the wrist, with ↑ latency and ↓ amplitude
What is the first-line conservative treatment for carpal tunnel syndrome?
Wrist splints at night
(to prevent flexion)
What other conservative treatments are available?
Corticosteroid injections
What surgical procedure is used for carpal tunnel syndrome?
Carpal tunnel decompression
= division of the transverse carpal ligament under local anaesthetic
What is the success rate of carpal tunnel decompression?
It is usually highly successful, though there is a small risk of damage to the median nerve or its branches
A 43-year-old office worker has a history of poorly controlled Type 1 diabetes mellitus.
Over the past 3 months, he has been having tingling in his first three digits, worse at night and in the office when he is typing. He can make the feeling go away after shaking his hand.
What is the most appropriate initial management for the likely diagnosis?
Wrist splint
A 35-year-old pregnant woman presents to the clinic with numbness, tingling, and pain in her right hand, particularly at night. She reports difficulty with fine motor tasks and the occasional dropping of objects.
What is the most likely diagnosis?
Carpal tunnel syndrome
A 60-year-old woman presents with tingling in her right hand which can occasionally wake her up at night. She generally shakes her hand to get rid of the symptoms which resolve completely. She has a background of poorly controlled type 2 diabetes and breast cancer.
On examination, she has good power throughout her hand and there doesn’t appear to be any deformity or wasting. Performing forced wrist flexion reproduces the symptoms.
What is the most appropriate initial management?
Wrist splinting
What action do patients with carpal tunnel syndrome commonly perform for relief?
Shaking their hand, especially at night
What muscle is weakened in carpal tunnel syndrome?
Abductor pollicis brevis (thumb abduction)
What sign is positive when tapping over the carpal tunnel produces paraesthesia?
Tinel’s sign
