Carpal Tunnel Syndrome

Essentials of Diagnosis

• Pain, burning, and tingling in the distribution of the median nerve

• Initially, most bothersome during sleep

• Late weakness or atrophy, especially of the thenar eminence

• Can be caused by repetitive activities using the wrist

• Commonly seen during pregnancy and in patients with diabetes mellitus or rheumatoid arthritis

General Considerations

• May occur due to fluid retention of pregnancy, in individuals with a history of repetitive use of the hands, or following injuries of the wrists

• Caused by compression of the median nerve between the carpal ligament and other structures within the carpal tunnel

• The contents of the tunnel can be compressed by

  • Synovitis of the tendon sheaths or carpal joints

  • Recent or malhealed fractures

  • Tumors

  • Tissue infiltration

  • Congenital syndromes (eg, mucopolysaccharidoses)

• There is a familial type in which no etiologic factor can be identified

• Can also be a feature of many systemic diseases, such as

  • Rheumatoid arthritis and other rheumatic disorders (inflammatory tenosynovitis)

  • Myxedema

  • Amyloidosis

  • Sarcoidosis

  • Leukemia

  • Acromegaly

  • Hyperparathyroidism

Symptoms and Signs

• Pain, burning, and tingling in the distribution of the median nerve; it is most bothersome at night

• A Tinel or Phalen sign may be positive (eTable 41–2)

  • A Tinel sign is tingling or shock-like pain on volar wrist percussion

  • The Phalen sign is pain or paresthesia in the distribution of the median nerve when the patient flexes both wrists to 90 degrees for 60 seconds

• The carpal compression test, in which numbness and tingling are induced by the direct application of pressure over the carpal tunnel, may be more sensitive and specific than the Tinel and Phalen tests (eTable 41–2)

• Muscle weakness or atrophy, especially of the thenar eminence, can appear later than sensory disturbances as compression of the nerve worsens

Differential Diagnosis

• Cervicobrachial pain syndromes

• Compression syndromes of the median nerve in the forearm or arm

• Mononeuritis multiplex

• Angina pectoris (when pain is left sided)

Imaging

• Ultrasound

  • Can demonstrate flattening of the median nerve beneath the flexor retinaculum

  • Sensitivity is estimated to be between 54% and 98%

Diagnostic Procedures

• Electromyography and nerve conduction studies show evidence of sensory conduction delay before motor delay, which can occur in severe cases

• Electrodiagnosis can provide information on focal median mononeuropathy at the wrist and can classify carpal tunnel syndrome from mild to severe

Conservative measures

• Hand activities should be modified and the affected wrist splinted in the neutral position for up to 3 months

• When a causative lesion is discovered, it should be treated appropriately

Medications

• Oral corticosteroids or nonsteroidal anti-inflammatory drugs can be tried

Surgery

• Carpal tunnel release

• Indications

  • Positive electrodiagnostic test

  • At least moderate symptoms

  • High clinical probability

  • Unsuccessful nonoperative treatment

  • Symptoms lasting longer than 12 months

Prognosis

• Both corticosteroid injection and surgery resolved symptoms but only decompressive surgery allows resolution of neurophysiologic changes

• Decompression with the use of vascularized flap coverage appears to have a higher success rate over simple repeated decompression

When to Refer

• If symptoms persist > 3 months despite conservative treatment, including the use of a wrist splint

• If thenar muscle (eg, abductor pollicis brevis) weakness or atrophy develops