-IBIS-1.5.0-
tx
musculoskeletal system
carpal tunnel syndrome
diagnoses
definition and etiology
definition:
An entrapment neuropathy of the median nerve and, less commonly, compression of the finger flexor tendons, producing paresthesias, atrophy, and weakness in the affected hand.
etiology:
The syndrome is caused by continuous pressure on the median nerve as it passes through the anterior carpal tunnel, which is defined by the carpal bones (proximally: pisiform and the tubercle of the navicular; distally: hook of the hamate and the tubercle of trapezium) and the transverse carpal ligament.
Many factors are associated with the narrowing of the carpal tunnel: acromegaly; myxedema; RA; tenosynovitis from repeated flexion/pronation/supination movements of the wrist (sewing, typing, driving); anterior dislocation or subluxation of the lunate bone; Paget's disease; swelling secondary to Colles' fracture of the distal end of the radius; strains or sprains of the wrist; premenstrual edema or edema of pregnancy; gout; tuberculosis; and amyloidosis.
Irritation of the nerve at the brachial plexus or along its route to the wrist such as at the elbow may make the median nerve more susceptible to irritation at the carpal tunnel: ("double crush phenomenon").
signs and symptoms
signs and symptoms:
The syndrome predominates in middle-aged women. It may be unilateral or bilateral.
Numbness or paresthesias of the palmar aspect of the thumb, middle, and radial half of the ring finger (median nerve distribution).
Occasional numbness or paresthesia of the entire hand may be present.
The pain and/or tingling is usually worse at night and may be relieved by shaking the hand.
In advanced cases thenar eminence atrophy can occur, even if no previous severe sensory problems had existed. Thenar muscle weakness may be apparent on physical exam, however, before atrophy begins to manifest.
lab or exam findings:
(+) Tinel's (tapping over the volar aspect of the wrist).
(+) Phalen's (reproduction of the symptoms by engaging the wrists in full flexion for 30-60 seconds).
Delayed latency of the median nerve during electrical nerve conduction tests.
X-rays and orthopedic examinations of the elbow, shoulder, brachial plexus, and cervical vertebrae should be carefully performed.
course and prognosis
The untreated course usually entails a gradually worsening situation. Conventional medicine attempts to surgically release the compression by resecting the flexor retinaculum, a procedure that is not 100% effective, and is often followed by the development of the syndrome in the other previously normal hand. This procedure is often attempted before conservative measures are used. If atrophy occurs and still no treatment is afforded, the hand may lose all or part of its ability to function.
differential diagnosis
Elbow, shoulder or cervical disease causing referred pain/paresthesias to the wrist
C6 root compression due to cervical osteopathy or space occupying lesion
Rule out: amyloidosis, pregnancy, acromegaly, rheumatoid inflammation, trauma, fibrosis.
Other musculoskeletal diseases or injuries.
footnotes