Carpal tunnel syndrome is a condition in which a nerve in your wrist comes under pressure. This causes pain, tingling or weakness, mainly in your forearm and hand.
Your carpal tunnel is a channel in your wrist. The bones of your wrist are arranged in a semi-circle that forms the sides and base of this channel; a tough band of tissue, known as the transverse carpal ligament, forms the roof. The tendons that you use to flex your fingers and wrist pass through your carpal tunnel. Your carpal tunnel also surrounds your median nerve, which supplies feeling and controls muscles in much of your hand and thumb. If this nerve comes under pressure, it can lead to carpal tunnel syndrome.
Carpal tunnel syndrome is more common in women than men. It affects about three in 100 men and four to five in 100 women at some point in their life. Children are unlikely to get carpal tunnel syndrome, unless their genetic make-up puts them more at risk.
If you have carpal tunnel syndrome, you may have symptoms including:
These symptoms mainly affect your wrist and hand. You're most likely to get these symptoms in your thumb, index and middle fingers and the side of your ring finger nearest to your thumb. You may also get aching or pain in your forearm, shoulder and neck.
Any weakness usually occurs in movements involving your thumb, so you may find it difficult to grip things, or have trouble carrying out actions such as fastening buttons. Over time, your hand muscles may continue to get weaker. If you have severe, long-lasting carpal tunnel syndrome, your thumb muscles may start to waste away or your median nerve may become permanently damaged.
It’s possible that your hand will change colour and the skin on your hand may become dry. You may also feel as though your fingers or hands are swollen, even though they don’t look it. If you have numbness, you may not be able to tell the different between hot and cold when you touch objects.
At first your symptoms may be mild or last for only short periods of time. They can occur at any time but often carpal tunnel syndrome is worse at night and may cause you to wake up. Your symptoms may get better after you have used your hand for a while, but then come back later in the day.
If you have any of these or similar symptoms, see your GP for advice.
There isn't much space in your carpal tunnel so any swelling there can press on your median nerve, causing the symptoms of carpal tunnel syndrome. There are many reasons why this may happen, but often it’s not possible to find a specific cause for the condition.
Some people simply have smaller carpal tunnels, which makes them more at risk of developing carpal tunnel syndrome. It’s thought that this tendency may run in families. Therefore, you may have a smaller carpal tunnel because other members of your family do, and so be more likely to develop problems if there is increased pressure on the nerve.
You're more likely to develop the condition if you're overweight, smoke or drink alcohol excessively. The condition is also more common as you get older. More women than men develop the condition, possibly because women naturally have smaller carpal tunnels.
You may be more likely to develop carpal tunnel syndrome if you have had an injury to your wrist such as a break or sprain, or have certain diseases, including:
It’s possible that hormones have something to do with carpal tunnel syndrome as some women develop the condition during pregnancy or the menopause. Hormones released during pregnancy can result in fluid retention, which in turn may cause swelling in your carpal tunnel. See our frequently asked questions for more information.
It may be that carrying out certain actions leads to carpal tunnel syndrome. People who do a lot of heavy manual work or repetitive actions such as assembly line packing, or who have a job that involves using their hands in cold temperatures may be more likely to get it, but there isn’t a great deal of evidence to support this as a single cause (see our frequently asked questions for more information). You’re more at risk if you do one of these jobs and also have a medical condition that makes you more likely to get carpal tunnel syndrome.
Your GP will ask you about your symptoms and examine you. He or she may also ask you about your medical history.
There is no single test that can confirm carpal tunnel syndrome. However, your GP may carry out the Tinel test in which he or she taps or presses on your median nerve in your wrist to see if you get any tingling in your fingers. Your GP may also ask you to do the Phalen test, which is more accurate. Your GP will ask you to flex your wrists – if you get any pain or numbness within one minute, it's possible that you have carpal tunnel syndrome.
If your GP suspects you may have carpal tunnel syndrome, he or she may refer you to a neurologist (a doctor who specialises in conditions that affect the nervous system) for a nerve conduction test. This test can show if there is any damage to your median nerve. During this test, your doctor attaches wires to your fingers and wrist, and applies small electric pulses to measure how quickly messages pass through your median nerve. However, it’s likely that your GP will only refer you for this if you’re considering surgery because no other treatment has helped to relieve your symptoms.
Treatment for carpal tunnel syndrome helps to relieve your symptoms by reducing the pressure on your median nerve. It may also stop your condition from getting any worse.
If you only have mild symptoms, they may improve without any treatment after about six months, especially if you're pregnant or under 30.
Resting your hands and wrists regularly may relieve mild symptoms of carpal tunnel syndrome. When your symptoms flare up, try applying a cold compress, such as an ice pack or ice wrapped in a towel. Don’t apply ice directly to your skin as it can damage your skin.
If repetitive hand movements are causing your condition, it's important to try to limit any activities that make your symptoms worse. It may help if you change the way you carry out these actions, reduce how often you do them and increase the amount of rest you take between periods of activity. Some people find that changing their mouse or keyboard shape can help, but there is only limited evidence for how effective this is.
You may be offered steroid injections directly into your carpal tunnel. Your pain may get a little worse for a couple of days after the injection, but your symptoms should improve after that. However, you may find that your symptoms return after a few months, especially if they were serious to begin with. There is no evidence that another injection will relieve your symptoms any further.
Your GP may prescribe corticosteroid tablets (eg prednisolone) in the short term to treat carpal tunnel syndrome. However, these medicines can cause side-effects if you take them for a long time. Always ask your GP for advice and read the patient information leaflet that comes with your medicines.
Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may help to relieve pain in the short term. However, they can cause side-effects and there is little evidence that they have much effect on carpal tunnel syndrome unless it's caused by an underlying inflammatory condition.
Diuretic medicines (water tablets) don't appear to have any effect on the symptoms of carpal tunnel syndrome.
Wrist splints help to keep your wrist straight and reduce pressure on the compressed nerve, and may relieve the symptoms of carpal tunnel syndrome. You’re likely to be advised to wear wrist splints at night for several weeks or months. You can wear splints during the day as well, but you may find that they get in the way when you're doing your daily activities.
There is some evidence to show that ultrasound treatment (using sound waves) can help to reduce the symptoms of carpal tunnel syndrome. However, further studies are required to determine the most effective way of using this treatment.
If your symptoms are severe or other treatments haven’t worked for you, your GP may suggest that you have carpal tunnel release surgery. This operation involves cutting your carpal ligament to make more space for the nerves and tendons in your carpal tunnel. There is good evidence that the procedure is effective for treating carpal tunnel syndrome.
There is no scientific evidence that any general hand or wrist exercises can relieve the symptoms of carpal tunnel syndrome. More research is needed to see whether special hand exercises - called nerve and tendon gliding exercises - can help.
There is some limited evidence to suggest that acupuncture helps to relieve symptoms of carpal tunnel syndrome if your symptoms are mild. However, there is no evidence to suggest that chiropractic, vitamin B6 (pyroxidine) tablets or magnets can help.
There is a small amount of evidence that yoga may help to reduce pain in some people with carpal tunnel syndrome, but more research is needed.
Always seek advice from your GP or pharmacist before trying any complementary therapies or medicines. If you choose to try a complementary therapy, check that your therapist is affiliated to a recognised organisation.
Produced by Polly Kerr, Bupa Health Information Team, June 2012.
For answers to frequently asked questions on this topic, see FAQs.
For sources and links to further information, see Resources.
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