Carpal Tunnel Syndrome

Question 1

ESSENCE

Answer 1

Compression of median nerve through carpal tunnel in wrist, causing pain and numbness in its distribution on hand

Question 2

AETIOLOGY

Pathophysiology

Answer 2

• Flexor retinuculum is fibrous band that wraps around palmar side of wrist
• Between this and carpal bones is passage called carpal tunnel where median nerve and flexor tendons from forearm travel to hand
• Compression of the contents of this leads to carpal tunnel syndrome

Question 3

Compression of carpal tunnel is caused by what

Answer 3

• Swelling of contents (eg swelling of tendon sheaths due to repetative injury)
• Narrowing of tunnel

Question 4

Median nerve supplies sensory innervation to

Answer 4

• Palmar digitial cutanoeus branch of median nerve
  
  • Palmar aspects of full fingetips of
    
    • Thumb
    • Index and middle finger
    • Lateral half of ring finger

Question 5

Although from median nerve why is palmar cutaneous branch not affected

Answer 5

Supplies sensation to hand and is from median nerve, but this branch does not travel through carpal tunnel

Question 6

Median nerve supplies motor function to

Answer 6

• Three thenar muscles
  
  • Abductor pollicis brevis
  • Opponens pollicis
  • Flexor pollicis brevis

Question 7

Actions of thenar muscles

Answer 7

• Abductor pollicis brevis - thumb abduction
• Opponens brevis - thumb opposition
• Flexor pollicis brevis - thumb flexion

Question 8

AETIOLOGY

Risk factors

Answer 8

• Usually idiopathic
• Repetitive strain
• Obesity
• Perimenopause
• RA
• Diabetes
• Acromegaly
• Hypothyroidism

Question 9

CLINICAL FEATURES

Presentation

Answer 9

• Gradual onset of symptoms, often worse at night
• Sensory symptoms of median distribution
  
  • Numbness
  • Paraesthesia
  • Burning sensation
  • Pain
• Motor symptoms of median distribution
  
  • Weakness of thumb movements
  • Weakness of grip strength
  • Difficult with fine movements involving thumb
  • Wasting of thenar muscles (muscle atrophy)

Question 10

What special tests are done

Answer 10

• Phalens
  
  • Hold hands fully flexed against each other, positive if triggers sensory symptoms of carpal tunnel
• Tinnels
  
  • Tapping wrist at location of median nerve, positive when triggers sensory symptoms of carpal tunnels

Question 11

INVESTIGATIONS

First choice

Answer 11

• Kamath and Stothard carpal tunnel questionaire
• Nerve conduction studies

Question 12

What is Kamath and Stothard carpal tunnel questionaire

Answer 12

• Predicts liklihood of carpal tunnel by giving score based on symptoms
  
  • Do symptoms wake you at night?
  • Do you have trick movements to improve symptoms (such as shaking of hand)
  • Is your little finger affected (yes scores negatively)

Question 13

MANAGEMENT

Management lines

Answer 13

• 1) Wrist splint
• 2) Corticosteroid injection and wrist splint
• 3) Surgical release

Question 14

MANAGEMENT

Surgery options

Answer 14

• Open or endoscopic surgery - flexor retinaculum is cut to release pressure