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Some people might think that carpal tunnel syndrome is a new condition of the information technology age, born from long hours of computer keyboarding. But carpal tunnel syndrome is nothing new. Evidence of people experiencing symptoms of carpal tunnel syndrome occurs in medical records dating back to the beginning of the 20th century.

Bounded by bones and ligaments, the carpal tunnel is a narrow passageway — about as big around as your thumb — located on the palm side of your wrist. This tunnel protects a main nerve to your hand and nine tendons that bend your fingers. Pressure placed on the nerve produces the numbness, pain and, eventually, hand weakness that characterize carpal tunnel syndrome.

Fortunately, for most people who develop carpal tunnel syndrome, proper treatment usually can relieve the pain and numbness and restore normal use of the wrists and hands.

Carpal tunnel syndrome typically starts gradually, with a vague aching in your wrist that can extend to your hand or forearm. Other common signs and symptoms include:

• Tingling or numbness in your fingers or hand, especially your thumb, index, middle or ring fingers, but not your little finger. This sensation often occurs while driving a vehicle or holding a phone or a newspaper, or upon awakening. Many people "shake out" their hands to relieve their symptoms.
• Pain radiating or extending from your wrist up your arm to your shoulder or down into your palm or fingers, especially after forceful or repetitive use. This usually occurs on the front (palm) side of your forearm.
• A sense of weakness in your hands, and a tendency to drop objects.
• A constant loss of feeling in some fingers. This can occur if the condition is advanced.

The cause of carpal tunnel syndrome is pressure on the median nerve. The median nerve is a mixed nerve, meaning it has a sensory function and also provides nerve signals to move your muscles (motor function). The median nerve provides sensation to your thumb, index finger, middle finger and the middle-finger side of the ring finger. Pressure on the nerve can stem from anything that reduces the space for it in the carpal tunnel. Causes might include anything from bone spurs to the most common cause, which is swelling or thickening of the lining and lubricating layer (synovium) of the tendons in your carpal tunnel.

The exact cause of the swelling usually isn't known, but a variety of conditions and factors can play a role:

• Other health conditions. Some examples include rheumatoid arthritis, certain hormonal disorders — such as diabetes, thyroid disorders and menopause — fluid retention due to pregnancy, or deposits of amyloid, an abnormal protein produced by cells in your bone marrow.
• Repetitive use or injury. Repetitive flexing and extending of the tendons in the hands and wrists, particularly when done forcefully and for prolonged periods without rest, also can increase pressure within the carpal tunnel. Injury to your wrist can cause swelling that exerts pressure on the median nerve.
• Physical characteristics. It may be that your carpal tunnel is more narrow than average. Other less common causes include a generalized nerve problem or pressure on the median nerve at more than one location.

Some studies suggest that carpal tunnel syndrome can result from overuse or strain in certain job tasks that require a combination of repetitive, forceful and awkward or stressed motions of your hands and wrists. Examples of these include using power tools — such as chippers, grinders, chain saws or jackhammers — and heavy assembly line work, such as occurs in a meatpacking plant. Although repetitive computer use is commonly assumed to cause carpal tunnel syndrome, the scientific evidence for this association is weak.

Although it's not clear which activities can cause carpal tunnel syndrome, if your work or hobbies are hand-intensive — involving a combination of awkward, repetitive wrist or finger motions, forceful pinching or gripping and working with vibrating tools — you may be at higher risk of developing the condition.

Other risk factors include:

• Sex. Women are three times as likely as men are to develop carpal tunnel syndrome. The incidence in women peaks after menopause, and the risk of carpal tunnel syndrome also increases in men during middle-age.
• Certain health conditions. Conditions including some thyroid problems, diabetes, obesity and rheumatoid arthritis can increase your risk. Women who are pregnant, taking oral contraceptives or going through menopause also are at increased risk, most likely due to hormonal changes. Fluid retention may be a cause of carpal tunnel syndrome during pregnancy. Fortunately, carpal tunnel syndrome related to pregnancy almost always improves after childbirth. People who smoke cigarettes may experience worse symptoms and slower recovery from carpal tunnel syndrome than nonsmokers do.

If signs and symptoms that you think might be due to carpal tunnel syndrome interfere with your normal activities — including sleep — and they persist, see your doctor. If you leave the condition untreated, nerve and muscle damage can occur.

Your doctor will most likely want to review your signs and symptoms to find out where they're located. One diagnostic key is that the median nerve doesn't provide sensation to your little fingers, so symptoms in those fingers may indicate a different problem. Another clue is the timing of the symptoms. Typical times when you might experience symptoms due to carpal tunnel syndrome include while holding a phone or a newspaper, gripping a steering wheel, or sleeping.

Your doctor will also want to test the feeling in your fingers and the strength of the muscles in your hand, because these can be affected by carpal tunnel syndrome. Pressure on the median nerve at the wrist, produced either by bending the wrist, tapping on the nerve or simply pressing on the nerve, can bring on the symptoms in many people.

If you have signs and symptoms of carpal tunnel syndrome, your doctor may recommend the following diagnostic tests:

• Electromyogram. Electromyography measures the tiny electrical discharges produced in muscles. A thin-needle electrode is inserted into the muscles your doctor wants to study. An instrument records the electrical activity in your muscle at rest and as you contract the muscle. This test can help determine if muscle damage has occurred.
• Nerve conduction study. In a variation of electromyography, two electrodes are taped to your skin. A small shock is passed through the median nerve to see if electrical impulses are slowed in the carpal tunnel.

These tests are also useful in checking for other conditions that might mimic carpal tunnel syndrome, such as a pinched nerve in your neck. Your doctor may recommend that you see a rheumatologist, neurologist, hand surgeon or neurosurgeon if your symptoms indicate other medical disorders or a need for specialized treatment.

Some people with mild symptoms of carpal tunnel syndrome can ease their discomfort by taking more frequent hand-rest breaks and applying cold packs to reduce occasional swelling. If these techniques don't offer relief, treatment options include wrist splinting, medications and surgery.

Nonsurgical therapy
Most people with carpal tunnel syndrome can be effectively treated with nonsurgical methods, including:

• Wrist splinting. A splint that holds your wrist still while you sleep can help relieve nighttime symptoms of tingling and numbness. Splinting is more likely to help you if you've had only mild to moderate symptoms for less than a year.
• Nonsteroidal anti-inflammatory drugs. NSAIDs may help relieve pain from carpal tunnel syndrome if you have an associated inflammatory condition. If no inflammatory condition is involved, NSAIDs are unlikely to help relieve your symptoms.
• Corticosteroids. Your doctor may inject your carpal tunnel with a corticosteroid, such as cortisone, to relieve your pain. Corticosteroids decrease inflammation, thus relieving pressure on the median nerve. Oral corticosteroids aren't as effective as corticosteroid injections for the symptoms of carpal tunnel syndrome.

Surgery
Generally, nonsurgical treatments are more effective if you have only mild nerve impairment. When the pain or numbness of carpal tunnel syndrome persists, surgery may be the best option.

Your surgeon may use one of a few accepted techniques. But in all accepted surgical procedures, your doctor cuts the ligament pressing on your nerve. At times, surgery can be done using an endoscope, a telescope-like device with a tiny television camera attached to it that allows your doctor to see inside your carpal tunnel and perform the surgery through small incisions in your hand or wrist. In other cases, surgery involves making an incision in the palm of your hand over the carpal tunnel and releasing the nerve.

Surgery usually results in marked improvement, but you may experience some residual numbness, pain, stiffness or weakness. Surveys of people who have undergone carpal tunnel release indicate that about 70 percent are completely or very satisfied with the outcome of their surgery. Some variables that are associated with lower levels of satisfaction include consuming more than two alcoholic drinks a day, smoking, lower mental and physical health status before surgery, and exposure to repetitive, forceful activity — but not including keyboard use.

After surgery, your doctor may tell you that limited use of your hand and wrist is OK within a few days. However, it may take from several weeks to as long as a few months before you have unrestricted use of your hand and wrist. If surgery appears to be the best alternative for relieving your symptoms or preventing further muscle atrophy, be sure to talk with your surgeon about the procedure that will work best for you and with your plans to return to your previous activity levels, both at work and at home.

If carpal tunnel syndrome results from an inflammatory arthritis, such as rheumatoid arthritis, then treating the underlying condition generally also reduces the carpal tunnel syndrome symptoms. This may not be the case with all underlying conditions, such as thyroid conditions or diabetes.

There are no proven strategies to prevent carpal tunnel syndrome, but to protect your hands from a variety of ailments, take the following precautions:

• Reduce your force and relax your grip. Most people use more force than needed to perform many tasks involving the hands. If your work involves a cash register, for instance, hit the keys softly. For prolonged handwriting, use a big pen with an oversized, soft grip adapter and free-flowing ink. This way you won't have to grip the pen tightly or press as hard on the paper.
• Take frequent breaks. Every 15 to 20 minutes give your hands and wrists a break by gently stretching and bending them. Alternate tasks when possible. If you use equipment that vibrates or that requires you to exert a great amount of force, taking breaks is even more important.
• Watch your form. Avoid bending your wrist all the way up or down. A relaxed middle position is best. If you use a keyboard, keep it at elbow height or slightly lower.
• Improve your posture. Incorrect posture can cause your shoulders to roll forward. When your shoulders are in this position, your neck and shoulder muscles are shortened, compressing nerves in your neck. This can affect your wrists, fingers and hands.
• Keep your hands warm. You're more likely to develop hand pain and stiffness if you work in a cold environment. If you can't control the temperature at work, put on fingerless gloves that keep your hands and wrists warm.

Quick breaks, stretching, aspirin or other over-the-counter NSAIDs may relieve your symptoms temporarily.

You might also want to try wearing a wrist splint at night and avoid sleeping on your hands to help ease the pain or numbness in your wrists and hands. The splint should be snug but not tight. If pain, numbness or weakness recurs and persists, see your doctor.

If you experience chronic pain or can't use your hands as before, you may become depressed or suffer from low self-esteem. In addition, if your hand symptoms are caused or worsened by your current profession or leisure activities, you may face the tough decision of switching careers or giving up hobbies. You may also feel that you aren't actively contributing to your family if you can't drive a car or perform ordinary household tasks.

Support groups for people with carpal tunnel syndrome can help you find out more information about your condition plus offer advice and solace. Stress management and relaxation techniques also may help you deal with the psychological and emotional issues that may accompany carpal tunnel syndrome.

Yoga and other relaxation techniques may help with chronic pain that occurs with some muscle and joint conditions. Yoga postures designed for strengthening, stretching and balancing each joint in the upper body, as well as the upper body itself, may help reduce the pain and improve the grip strength of people with carpal tunnel syndrome.

Other options for treatment involve special types of physical therapy. Many of the methods used for carpal tunnel syndrome include:

• Heat
• Massage
• Chiropractic manipulation
• Osteopathic manipulation
• Water therapy (hydrotherapy)

Ultrasound treatments may be used, but have had variable results in studies. The National Institutes of Health has released a consensus statement acknowledging that acupuncture also may be useful for treating the symptoms of carpal tunnel syndrome. However, magnet therapy, laser acupuncture and chiropractic care haven't provided the same benefits in controlled trials.

You may have to experiment to find a treatment that works for you. Still, always check with your doctor before trying any complementary or alternative treatment.