Carpal tunnel syndrome

Update of a Patient Note originally published in September 1995.

Download this Patient Note in PDF format

Lately, one of your wrists has begun to ache as you drive to work in the morning. The pain goes away when you get to work, but it's there again the next morning. You've begun to suspect that this discomfort could be a symptom of carpal tunnel syndrome.

What is carpal tunnel syndrome?
It is a narrowing of the carpal tunnel, a narrow tunnel of space under the ligament on the underside of the wrist. The tunnel protects the main (median) nerve to the hand and the tendons that bend the fingers.

What causes this syndrome?
It occurs when prolonged pressure is placed on the carpal tunnel over months or years, squeezing the median nerve between bone and ligament. This pressure may also result from bone spurs or growths in the wrist, rheumatoid arthritis, diabetes, obesity, thyroid disease, pregnancy, or menopause.

Carpal tunnel syndrome may occur after repetitive stress, such as that caused by working in certain professions. Supermarket checkers, construction workers who use vibrating power tools, farmers, assembly-line workers, typists, musicians, tennis players, and others who use their hands in repetitive, forceful movements are thought to be at risk of carpal tunnel syndrome. Women are three times as likely as men to have this condition, which occurs most often between ages 45 and 54 years.

What are the symptoms of carpal tunnel syndrome?
Symptoms begin gradually and include numbness, pain, a pins-and-needles sensation, and a weakness in the wrist that extends down to the thumb or to the index, middle, or ring finger and up the underside of the arm to the shoulder. These symptoms usually come and go, occurring at night, first thing in the morning, or while driving or holding a phone or newspaper.

How is the syndrome diagnosed?
It is important to seek medical treatment if symptoms of carpal tunnel syndrome interfere with your normal activities. If left untreated, the syndrome can lead to permanent nerve and muscle damage.

Your doctor may tap the median nerve with a finger to see if this action produces symptoms. Or he or she may do a test called an electromyogram, in which a tiny electrode is inserted into muscles in your wrist to measure the electrical activity in the muscles during movement and at rest. Another test uses two electrodes attached to the skin to measure electrical activity that travels to the median nerve.

How is carpal tunnel syndrome treated?
In some cases, taking a nonsteroidal anti-inflammatory drug such as ibuprofen and applying ice to the wrist may help relieve the swelling and discomfort. If the condition is mild, resting your hand often, keeping the hand and wrist warm, and using a special wrist splint while you sleep may be all that is needed. Your doctor may also give an injection of a corticosteroid or a prescription for an oral corticosteroid. Some people have found relief with such therapies as acupuncture and massage.

If these methods don't work, surgery to widen the carpal tunnel may be needed. The surgeon may be able to operate through an endoscope, a thin tube with a tiny television camera on it, inserted through several small cuts in the wrist or hand. Another common approach to surgery is to make a cut in the palm of the hand over the carpal tunnel. These operations generally don't require an overnight stay in the hospital, but their success does require at-home exercises to help regain strength in the wrist and hand. Although surgery usually helps relieve the discomfort, some symptoms may be lasting.

How can I prevent carpal tunnel syndrome?
The following steps may be helpful:

• At your job, make sure you have a work station that is ergonomic (that is, designed to reduce repetitive stress on your hands and wrists). A keyboard should be at elbow height or just slightly lower to avoid repeated flexing of the wrists.
• Every 20 minutes, take a short break in which you give your hands and wrists a rest and do something else.
• When writing, grasp the pen or pencil lightly.
• When typing, strike the keys softly.
• Keep your back straight while sitting at your desk.

For more information on carpal tunnel syndrome American Chronic Pain Association PO Box 850 Rocklin, CA 95677 800-533-3231 http://www.theacpa.org National Chronic Pain Outreach Association PO Box 274 Millboro, VA 24460 540-862-9437 http://www.chronicpain.org National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse National Institutes of Health 1 AMS Circle Bethesda, MD 20892 877-226-4267 http://www.niams.nih.gov

This information is not a substitute for medical treatment.

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