Carpal Tunnel Syndrome: Causes, Symptoms and Treatment

Carpal tunnel syndrome is a common set of problems, numbness, tingling, weakness or pain in the wrist or hand, that happens when a nerve in the wrist is squeezed.

The carpal tunnel

The carpal tunnel is a narrow passage between the wrist bones and the ligament that holds them together. Through it run:

• the median nerve, from the forearm into the hand, which gives feeling to the thumb and first three fingers and helps move the thumb;
• tendons connecting the finger bones to forearm muscles, which let the fingers bend.

If the tendons swell or become irritated inside the tunnel, they can press on the nerve, which then may not work well.

Causes

Sometimes the cause is unknown, but usually it is a combination of things affecting the wrist:

• a wrist injury that causes swelling, such as a sprain or fracture;
• conditions affecting the nerves, joints or other parts of the wrist, such as diabetes, rheumatoid arthritis, or a cyst or tumor;
• hormonal changes that cause fluid swelling, such as an underactive thyroid (hypothyroidism), pregnancy or menopause;
• a wrist shaped in a way that causes problems;
• repeating the same hand and wrist movements, as in assembly line work, carpentry or vibrating tools, knitting, gardening, or sports such as golf.

Researchers aren't sure whether long-term typing or computer use causes it.

Who gets it

It usually affects only adults. The risk is higher for:

• women, three times as likely as men;
• people with conditions that affect the wrist;
• people whose activities involve repeated hand motions;
• people with a past wrist injury;
• people with a parent, brother or sister who has had it.

Symptoms

Numbness, tingling or burning in the fingers, especially the thumb, index and middle fingers, often in both hands.

• Early on, symptoms usually start slowly in the dominant hand, and come at night if you sleep with your wrists bent.
• Later, there may be tingling, pain or weakness during activities such as driving or holding a phone, trouble gripping small objects, and fingers that feel swollen when they aren't.

Untreated, it can cause lost feeling in some fingers and permanent thumb weakness, so early diagnosis and treatment matter.

Diagnosis

A provider asks about your medical and family history, does a physical exam, and may order lab tests for nerve-damaging diseases, X-rays for fractures or arthritis, tests of electrical activity in nerves and muscles, or an ultrasound of the nerve.

Treatment

Treatment is easier early. The provider first treats any underlying condition, then may recommend:

• wrist splints, usually worn at night, and rest;
• medicines for swelling and pain: over-the-counter aspirin, ibuprofen or naproxen sodium, or prescription steroids as pills or a wrist injection;
• complementary therapies: research shows yoga may help with pain and weakness; some people find acupuncture or chiropractic care helpful, though research hasn't shown they improve the condition. Talk with a provider first;
• surgery, if symptoms are severe and other treatments fail, cutting the wrist ligament to relieve pressure on the nerve. Recovery can take months; the condition rarely returns, though mild symptoms may linger.

Prevention

Protect your wrists: keep them in a natural position with good posture, keep your hands warm (fingerless gloves may help), take breaks and vary tasks, stretch and exercise your hands and wrists, and arrange your workspace and tools to reduce strain.

Sources

• MedlinePlus, produced by the U.S. National Library of Medicine, "Carpal Tunnel Syndrome": https://medlineplus.gov/carpaltunnelsyndrome.html