Carpal tunnel syndrome is a condition in which the median nerve is squeezed where it passes through the wrist. This nerve controls some of the muscles that move the thumb; it also carries information back to the brain about sensations in your thumb and fingers.
When the nerve is squeezed it can cause pain or aching, tingling or numbness in the affected hand. Women are more likely than men to develop carpal tunnel syndrome, and although the condition affects people of all ages, it’s more common in the middle aged and elderly.
‘Carpal’ is a medical term that refers to the wrist. A ‘syndrome’ is a combination of problems which doctors recognize as a particular disease or disorder.
Carpal tunnel syndrome causes pain, aching, tingling or numbness in the hand. It tends to come on gradually, over a period of weeks. The symptoms are usually worse in the thumb, index and middle fingers, but sometimes it may feel like your whole hand is affected. You may also have an ache extending up the arm to your shoulder or neck. It can affect either one or both hands.
The symptoms tend to be worse at night and may disturb your sleep; you may notice it most when you wake up in the morning. Hanging your hand out of bed or shaking it around will often relieve the pain and tingling.
You may not notice the problem at all during the day, though certain activities – such as writing, typing, DIY or housework – can bring on symptoms. However, if the nerve is badly squeezed you may have symptoms throughout the day. Your hand may feel weak, or the fingers numb, or both. You may have a tendency to drop things and you may find that activities which require fine finger movements, like writing or fastening buttons, become more difficult.
The median nerve is very sensitive to pressure, and it may not be possible to say what the cause is in your particular case. However, some of the possible causes are:
Your risk of developing carpal tunnel syndrome may be greater if your job places heavy demands on your wrist, or if you use vibrating tools.
Your doctor will examine your hand and wrist to try to confirm the diagnosis and to assess how severe it is. If the wrist is swollen due to arthritis or tendon swelling, this could be the cause of your symptoms. If you’ve had the condition for some time there may be signs of muscle wasting at the base of the thumb. If the problem is severe, the thumb, index and middle fingers may be insensitive (numb) to either a gentle touch or a pin prick.
Your doctor may also tap over the median nerve on the palm side of your wrist (Tinel’s test) or ask you to bend your palm towards your forearm for up to a minute (Phalen’s test). These tests can help to confirm carpal tunnel syndrome, though they aren’t fully reliable so you may have one of the tests described below.
Sometimes the condition can be mistaken for something else. For example, pressure on nerves in the neck due to disc problems or arthritis can cause similar symptoms. A nerve conduction test may help if there’s any doubt about the diagnosis or to see how severe the compression of the nerve is. These tests can be done in several ways but one common measurement is made by stimulating a finger with a small electric current while recording the response of the median nerve at the wrist with a pair of electrodes attached to the skin. When the nerve is impaired, the speed of conduction between the finger and the wrist is slower.
Many different treatments have been suggested for carpal tunnel syndrome but only a few have been proven to work. Not all cases are progressive and some may improve without any medical treatment. Importantly, if there’s a particular cause for your problem (for example underactive thyroid gland, arthritis) then your symptoms may improve simply by treating that.
Your doctor will advise you which treatments are available, and they’ll help to decide which is most appropriate for you.
The decision is usually affected by how severe the compression of the nerve is. If it’s severe and there’s weakness of your hand muscles, then it’s important to get treatment quickly, and you’ll normally be advised to have surgery.
Simple treatments can often help, including:
An occupational therapist or physiotherapist will be able to advise you about the different types of splint. Similarly, some therapists recommend certain exercises of the wrist which might help prevent the median nerve becoming stuck to nearby tendons.
A steroid injection can be helpful, although the effect may wear off after weeks or months. A small quantity of steroid is injected into the carpal tunnel, which helps to reduce any swelling. The injection may rarely be uncomfortable, but it can be very effective. A steroid injection into the wrist joint itself may help if you have arthritis in your wrist.
You may need surgery if there’s severe compression of the median nerve or if the numbness and pain doesn’t improve with other treatments.
Carpal tunnel release surgery relieves pain by reducing the pressure on the median nerve. Surgery usually takes place as a day case and you can expect to recover in less than a month. The operation is normally carried out under a local anaesthetic and usually leaves only a small scar.
If you’ve had carpal tunnel syndrome for a long time – especially if you have muscle-wasting or loss of sensation – the operation may not bring a complete recovery, but the pain should be greatly reduced. For most people surgery is very successful, but, as with all surgical treatments, some people will have complications.
No particular diet has been shown to help either to relieve or prevent carpal tunnel syndrome. However, a healthy, balanced diet and regular exercise are important for your general health. One preliminary study suggested that yoga might give short-term improvements in pain and function in those people with mild symptoms.
If you think your work may be causing your symptoms you should discuss this with your supervisor or an occupational health nurse. If necessary, your local JobCentre Plus office can put you in touch with a Disability Employment Advisor who’ll be able to advise on changes to your equipment or working techniques.
There’s ongoing research looking into the causes of carpal tunnel syndrome, particularly whether it can be prevented by altering the way people carry out different tasks with their hands in the workplace. Other treatments, such as acupuncture and therapeutic ultrasound, are also being evaluated, and there’s active research into the best dose and timing of steroid injections.
Diabetes – A medical condition that affects the body’s ability to use glucose (sugar) for energy. The body needs insulin, normally produced in the pancreas, in order to use glucose. In diabetes the body may produce no insulin or not enough insulin, or may become resistant to insulin. When the body is unable to use glucose obtained from foods the level of sugar in the blood increases.
Median nerve – The nerve that controls movement of the thumb and carries information back to the brain about sensations felt in the thumb and fingers.
Occupational therapist – A trained specialist who who uses a range of strategies and specialist equipment to help people to reach their goals and maintain their independence by giving practical advice on equipment, adaptations or by changing the way you do things (such as learning to dress using one handed methods following hand surgery).
Physiotherapist – A trained specialist who helps to keep your joints and muscles moving, helps ease pain and keeps you mobile.
Tendon –A strong, Fibrous band or cord that anchors muscle to bone.
Thyroid gland – A gland at the front of the neck that produces various hormones which help to regulate the body’s internal processes, such as metabolism, reproduction, growth and development.