Carpal Tunnel Syndrome - Causes, Symptoms And Treatment

Carpal tunnel syndrome, a form of repetitive stress injury, is the most common nerve entrapment syndrome. Carpal tunnel syndrome usually occurs in women between ages 30 and 60 (posing a serious occupational health problem). However, men who are employed as assembly-line workers and packers or who repeatedly use poorly designed tools, may also develop this disorder. Any strenuous use of the hands - sustained grasping, twisting, or flexing - aggravates this condition.

Causes of carpal tunnel syndrome

Carpal tunnel syndrome is mostly idiopathic, or it may result from:

• repetitive stress injury
• rheumatoid arthritis
• flexor tenosynovitis (commonly associated with rheumatic disease)
• nerve compression
• pregnancy
• multiple myeloma
• diabetes mellitus
• acromegaly
• hypothyroidism
• amyloidosis
• obesity
• benign tumor
• other conditions that increase fluid pressure in the wrist, including alterations in the endocrine or immune systems
• wrist dislocation or sprain, including Colles' fracture followed by edema.

The carpal bones and the transverse carpal ligament form the carpal tunnel. Inflammation or fibrosis of the tendon sheaths that pass through the carpal tunnel usually causes edema and compression of the median nerve. This compression neuropathy causes sensory and motor changes in the median distribution of the hands, initially impairing sensory transmission to the thumb, index finger, second finger, and inner aspect of the third finger.

Signs and symptoms of carpal tunnel syndrome

The patient with carpal tunnel syndrome usually complains of weakness, pain, burning, numbness, or tingling in one or both hands. This paresthesia affects the thumb, forefinger,middle finger, and half of the fourth finger. The patient is unable to clench her hand into a fist; the nails may be atrophic, and the skin may be dry and shiny.

Because of vasodilation and venous stasis, symptoms typically are worse at night and in the morning. The pain may spread to the forearm and, in severe cases, as far as the shoulder. The patient usually can relieve such pain by shaking or rubbing her hands vigorously or dangling her arms at her side.

• Continued use of the affected wrist may increase tendon inflammation, compression, and neural ischemia, causing a decrease in wrist function.
• Untreated, carpal tunnel syndrome can produce permanent nerve damage with loss of movement and sensation.

Diagnosis information

Physical examination reveals decreased sensation to light touch or pinpricks in the affected fingers. Thenar muscle atrophy occurs in about half of all cases of carpal tunnel syndrome, but is usually a late sign.

The following tests provide rapid diagnosis of carpal tunnel syndrome:

• Tinel's sign - tingling over the median nerve on light percussion.
• Phalen's maneuver - holding the forearms vertically and allowing both hands to drop into complete flexion at the wrists for 1 minute, which reproduces symptoms of carpal tunnel syndrome.
• compression test - blood pressure cuff inflated above systolic pressure on the forearm for 1 to 2 minutes,which provokes pain and paresthesia along the distribution of the median nerve.

Other tests include electromyography to detect a median nerve motor conduction delay of more than 5 msec and laboratory tests to identify underlying disease.

Carpal tunnel syndrome treatment

Conservative treatment should be tried first, including resting the hands by splinting the wrist in neutral extension for 1 to 2 weeks. Nonsteroidal anti-inflammatory drugs usually provide symptomatic relief. Injection of the carpal tunnel with hydrocortisone and lidocaine may provide significant but temporary relief. If a definite link has been established between the patient's occupation and the development of repetitive stress injury, she may have to seek other work. Effective treatment may also require correction of an underlying disorder. When conservative treatment fails, the only alternative is surgical decompression of the nerve by resecting the entire transverse carpal tunnelligament or by using endoscopic surgical techniques. Neurolysis (freeing of the nerve fibers) may also be necessary.

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Tips on relieving carpal tunnel syndrome

• Prop up your arm with pillows when you lie down.
• Avoid using your hand too much.
• Find a new way to use your hand by using a different tool.
• Try to use the other hand more often.
• Avoid bending your wrists down for long periods.

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Special considerations or Prevention

Consider the following patient care for carpal tunnel syndrome:

• Administer mild analgesics as needed. Encourage the patient to use her hands as much as possible. If her dominant hand has been impaired, you may have to help her with eating and bathing.
• Lose weight if you're overweight.
• Teach the patient how to apply a splint. Tell her not to make it too tight. Show her how to remove the splint to perform gentle range-of motion exercises, which should be done daily. Make sure the patient knows how to do these exercises before she's discharged.
• After surgery. monitor vital signs and regularly check the color, sensation, and motion of the affected hand.
• If you use a keyboard a lot, adjust the height of your chair so that your forearms are level with your keyboard and you don't have to flex your wrists to type.
• Advise the patient who is about to be discharged to exercise her hands occasionally in warm water. If the arm is in a sling, tell her to remove the sling several times per day to do exercises for her elbow and shoulder.
• Suggest occupational counseling for the patient who has to change jobs because of repetitive stress injury.
• Don't work with your arms too close or too far from your body.