Carpal tunnel syndrome

Background

• Also known as "Median Mononeuropathy"
• Most common focal mononeuropathy
• Results from compression of median nerve at wrist where it traverses the carpal tunnel
• Median nerve provides sensation to the palmar aspect digits 1-3 and radial side of 4th
• Etiology: repetitive wrist flexion/extension, trauma, edema

Risk factors

• Diabetes mellitus
• Amyloidosis
• Obesity
• Pregnancy
• Hypothyroidism

Clinical Features

History

• Pain, paresthesia, and numbness in distribution of median nerve
  • Palmar aspect of thumb, index, middle, and radial aspect of ring finger
• Awakening at night with burning pain and tingling in hand

Physical

• Sensation testing
  • Most specific - splitting of 4th digit in which medial aspect of 4th digit normal and lateral aspect abnormal
  • Most sensitive - abnormal sensation of distal palmar tip of 2nd digit
• LOAF muscle weakness as compared to other hand - Lumbricals, with thumb Opposition, Abduction, Flexion
• Tinel sign - poorly sensitive and specific
  • Tapping on palmar aspect of wrist reuslts in electric shock sensation shooting into hand
  • SN 0.50 and SP 0.77
• Phalen maneuver
  • Holding wrists in flexion for 60 seconds evokes or worsens symptoms
  • SN 0.68 and SP 0.73
• Durkan sign
  • Manual compression of carpal tunnel reproduces symptoms after 30 seconds
  • SN 0.64 and SP 0.83
  • More sensitive and specific than Tinel and Phalen in earlier studies

Differential Diagnosis

By Type of Lestion

Proximal Lesion

• Spinal cord lesion
• Cervical radicular pain
• Thoracic outlet syndrome
• Multiple Sclerosis (MS)

Distal Lesion

• Ulna neuropathy

Systemic condition

• Raynaud syndrome
• Pregnancy (Main)
• B12 deficiency
• Diabetic neuropathy
• Hypothyroidism
• Hypocalcemia

Upper extremity peripheral nerve syndromes

Median Nerve Syndromes

• Carpal tunnel syndrome
• Pronator teres syndrome
• Anterior interosseous neuropathy

Ulnar Nerve Syndromes

• Ulnar neuropathy

Radial Nerve Syndromes

• Radial neuropathy at the spiral groove (ie. "Saturday night palsy")
• Posterior interosseous neuropathy

Proximal Neuropathies

• Suprascapular neuropathy
• Long thoracic neuropathy
• Axillary neuropathy
• Spinal accessory neuropathy
• Musculocutaneous neuropathy

Other

• Brachial plexopathy
  • Parsonage-Turner syndrome
• Cervical radiculopathy

Management

• See this American Academy of Orthopedic Surgeons clinical decision tool for treatment options and disposition - CTS guidelines
• Behavioral modification
• Wrist splint with wrist in neutral position
• NSAIDs (although not clearly effective)
• Diuretics (if edema is significant contributor to patient's symptoms)

Disposition

• Discharge

See Also

• Radial neuropathy at the spiral groove