The median nerve is a large nerve that travels down the centre of the forearm to the skin of the thumb, the index finger, the long middle finger and half of the third, or ring, finger. It also supplies sensation to the muscles of the base of the thumb.

To enter the hand the median nerve must pass through the narrow opening at the wrist joint. On one side of the wrist joint are bones, and on the other is a strong ligament that runs across the wrist. The ligament and the bones form a firm channel that has little ability to expand. Therefore, if this ‘tunnel’ becomes swollen or narrowed any resulting pressure is applied within. Several tendons also pass through this tunnel but it is the median nerve, being the most sensitive nerve in the area, that is most prone to damage from this type of pressure.

If any nerve in the body is bumped or has sustained pressure applied to it, this can cause sensory changes such as tingling or numbness. For example, bumping the 'funny bone' at the elbow can cause tingling or numbness in the fingers. When pressure is applied to a nerve for a long period this can cause loss of 'motor power' that the nerve supplies to the muscle. For example, if a person sits in an uncomfortable position for a long period of time this can put pressure on the nerves in the legs, causing them to ‘go to sleep’ and feel temporarily paralysed. This same phenomenon occurs with carpal tunnel syndrome, except that with carpal tunnel syndrome the pressure is more constant and ongoing and the resulting symptoms more sustained.

Carpal tunnel syndrome can come on suddenly, but more often begins gradually. It may affect one or both hands. If you have carpal tunnel syndrome your earliest symptoms will probably be pain, tingling or numbness in the thumb or the fingers, with the exception of the little finger. Usually only the inner side of the third finger is affected.

Your fingers may feel 'full' or swollen, and you could have pain that extends from your hand up your arm, possibly all the way to the elbow. These symptoms will probably feel worse at night, particularly when your hand is warm. Many people with carpal tunnel syndrome feel relief of their symptoms when they remove the affected hand from underneath sheets and blankets in order to cool it.

You might also notice weakness in your hand, particularly when doing activities that require involvement of the thumb, such as pinching or grasping. This can result in you dropping things more than usual.

The muscles at the base of your thumb, on the side closest to the palm, will probably become smaller than those on the other hand or than they used to be. This 'wasting' of muscles usually only occurs after the earlier symptoms of numbness and tingling have been present for some time.

In many cases the cause of carpal tunnel syndrome is not known and it can seem to appear for no reason. However, there are certain conditions that increase the risk of carpal tunnel syndrome. For example, an injury to the wrist that results in damage to the bone can cause carpal tunnel syndrome. Various forms of arthritis that result in inflammation of the lining of the wrist joint also cause pressure on the median nerve.

Hobbies and occupations that require heavy use of the hand and wrist can also play a role in carpal tunnel syndrome, particularly if the use involves repetitive movements. People who work as construction workers or carpenters; fish, meat and poultry processors; hairdressers;
needle workers or knitters; typists or computer operators can be more at risk of getting carpal tunnel syndrome.

Diabetes may also play a role in the development of carpal tunnel syndrome, as may hormonal changes. Some women develop swelling in the hands and feet when pregnant, after giving birth or during menopause.

If your doctor thinks you have carpal tunnel syndrome he or she will perform a physical examination of the area and may do specific tests.

One test that might be done is called Tinel's test. This involves tapping gently on the front of the wrist, which may cause tingling or pain in the hand. Another test is called Phalen's test. In this test, your wrist will be bent fully forward and then held in that position for a period of time. This may produce tingling or numbness in the fingers.

When the diagnosis is unclear and the problem has persisted despite other attempts to diagnose it, an electrical nerve conduction test can be useful. This test usually requires going to a special clinic. An electrical stimulation is sent down the nerve from various points in the upper arm and forearm. The time it takes for that electrical message to reach a point in the hand is carefully measured. It may show that while the nerve in the upper arm and forearm are carrying the message normally, when the message gets to the wrist it is slowed down or reduced in intensity.

X-Rays may also be taken, but if you have carpal tunnel syndrome the x-rays will probably be normal unless there is an obvious change in the bones due to earlier fractures or damage from arthritis. Blood tests also usually come back normal unless they indicate another condition such as rheumatoid arthritis that could be contributing to the problem.

Once the diagnosis is confirmed various treatments can help decrease your pain and stiffness and increase sensation in your hand. Your active involvement in developing your prescribed treatment plan is essential.

Medicine

NSAIDs reduce pain when taken at a low dose, and relieve inflammation when taken at a higher dose. NSAIDs such as ASA (Aspirin, Anacin, etc.) and ibuprofen (Motrin IB, Advil, etc.) can be purchased without a prescription. Examples of NSAIDs that require a prescription include Naprosyn, Relafen, Indocid, Voltaren, Feldene, and Clinoril. The various NSAIDs and Aspirin®, if taken in full doses, usually have the same levels of anti-inflammatory effect. However, different individuals may experience greater relief from one medication than another. Taking more than one NSAID at a time increases the possibility of side effects, particularly stomach problems such as heartburn, ulcers and bleeding. People taking these medications should consider taking something to protect the stomach, such as misoprostol (Cytotec).

For severe pain and inflammation, doctors can inject a powerful anti-inflammatory drug, called a corticosteroid, directly into the affected joint. Corticosteroids are man-made drugs that closely resemble cortisone. Cortisone is a steroid that reduces inflammation and swelling. It is a hormone naturally produced by the body. An injection of corticosteroids can provide almost immediate relief for a tender, swollen and inflamed joint. However, this treatment can only be used rarely, since corticosteroids can weaken cartilage and remove the minerals from (and therefore weaken) the bone, resulting in further joint weakness.

Heat/Cold

Heat or cold application can provide temporary relief of pain. Heat helps to reduce pain and stiffness by relaxing aching muscles and increasing circulation to the area. There is some concern that heat may worsen the symptoms in an already inflamed joint. Cold helps numb the area by constricting the blood vessels and blocking nerve impulses in the joint. Applying ice or cold packs appears to decrease inflammation and therefore is the method of choice when joints are inflamed.

Protect Your Joints

Protecting your joints means using them in ways that avoid excess stress. Benefits include less pain and greater ease in doing tasks. Three main techniques to protect your joints are pacing, positioning your joints wisely and using helpful devices.

Pacing, by alternating heavy or repeated tasks with easier tasks or breaks, reduces the stress on painful joints and allows weakened muscles to rest.

If you are doing an activity that could have a role in causing carpal tunnel syndrome, it is important to stop this activity or change how you do it. For example, a wood carver might use a hammer to hit a chisel rather than hitting it with a bare hand. A person who spends long hours knitting may have to take short breaks at regular intervals.

Positioning joints wisely helps you use them in ways that avoid extra stress. Use larger, stronger joints to carry loads. For example, use a shoulder bag instead of a hand-held one.  Also, avoid keeping the same position for a long period of time. 

Using helpful devices, such as luggage carts, grocery carts and reaching aids, can help make daily tasks easier. Small appliances such as microwaves, food processors and bread makers can be useful in the kitchen.

A splint may be useful if you have joint inflammation, or problems with joint alignment or stability. They can help rest your joints at night, or hold the joints in a comfortable position while working. This, in turn, helps decrease joint pain, swelling and stiffness. Your doctor will be able refer you to a therapist who can help find the best splint for you.

Relaxation

Developing good relaxation and coping skills can give you a greater feeling of control over your arthritis and a more positive outlook.

Surgery

When other treatment has not been successful and your symptoms persist, you and your doctor may decide to have surgery done on your wrist. This procedure, called carpal tunnel release, relieves the pressure on the median nerve.

Carpal tunnel release surgery is usually done as outpatient day surgery. If hospitalization is required it is usually only for a minimal period of time. It may take several weeks for full recovery, and it will probably be necessary for you to restrict hand and wrist activity for a week or two to assist in full healing. Those people who have jobs that require heavy manual labour may require several weeks away from work. Results of the surgery will depend in part on how long the loss of sensation and muscle wasting has been present.

Along with the physical symptoms of arthritis, many people experience feelings of helplessness and depression. Learning daily living strategies to manage your arthritis gives you a greater feeling of control and a more positive outlook. To get the best results, people affected by arthritis need to form close ties with their doctors and therapists, and become full partners in their treatment. From our perspective, it's all part of 'living well with arthritis.' There are several resources you can use in finding out how best to manage your own arthritis. Here are a few:

• The Arthritis Self-Management Program (ASMP) is a unique self-help program offered by The Arthritis Society to help you better control and manage your arthritis.
• The Open Forum within this Web site is an opportunity to discuss and share information with other visitors - people who, through their own experiences, may be able to offer some useful insights.

Of course, there are many other valuable resources for people with arthritis. If you're unclear about where to look for help, be sure to call The Arthritis Society at 1-800-321-1433.