Taming carpal tunnel syndrome

Inside your wrist, a slick tunnel passes through the carpal bones. The nerves and tendons of the wrist pass through this space, called the carpal tunnel. One of these nerves, the median nerve, controls sensations in the palm side of the thumb, the index and middle fingers, and half of the ring finger. It also transmits the impulses to certain hand muscles that allow the fingers and thumb to move. Carpal tunnel syndrome occurs when this nerve becomes irritated or squeezed. Symptoms include numbness, tingling, pain, or weakness in the hand of the affected wrist.

Because the carpal tunnel starts out narrow, it doesn't take much to aggravate or compress the median nerve. A number of conditions can make a person more prone to carpal tunnel syndrome. These include:

• arthritis or fracture near the wrist
• pregnancy
• diabetes
• being overweight or obese
• overuse (for example, from the repetitive motions of some jobs or sports)
• thyroid disease, particularly an underactive thyroid

Sometimes there is no clear cause.

Relieving the symptoms of carpal tunnel syndrome

• Things you can do on your own: Try to rest the affected hand for at least two weeks, and avoid the activities that worsen symptoms. It can help to wear a splint that keeps your wrist in a neutral position. Many people find that wearing a splint at night helps a lot. Some hand exercises may be helpful for people with carpal tunnel syndrome, but it's best to consult your doctor or a physical therapist. The wrong exercises, or exercises done improperly, may worsen the condition.

• Medications. Nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen, and naproxen can help relieve pain but won't cure carpal tunnel syndrome. Steroid injections into the carpal tunnel can also help, especially in younger people who have had symptoms only for a short time. Studies on the long-term benefits of steroid injections have had mixed results, with some finding that, for most people, pain returns within two to four months.

• Surgery. For people with persistent numbness, pain, or reduced hand function that doesn't respond to standard treatment, surgery may be an option. The goal of surgery is to create more space in the tunnel by releasing the transverse carpal ligament, which relieves pressure on the median nerve. Most often this procedure is day surgery and doesn't require general anesthesia.

For more information on the causes and treatment of hand pain, read Healthy Hands, a Special Report from Harvard Medical School.