Carpal Tunnel Syndrome (CTS) is a condition in which the median nerve becomes compressed as it passes through the carpal tunnel in the wrist causing pain, numbness and tingling in the hand. The median nerve passes down the arm through the carpal tunnel and into the palm where it sends branches to the thumb, index, middle and the side of the ring finger next to the thumb. It is responsible for both the sensory feelings and the motor or movement in the hand. It is thought to affect one in ten people over a lifetime with more women than men suffering and the most common age is between 45 and 65 years. In this article we will look at the signs and symptoms, the possible causes, diagnosis, treatment and the types of jobs which put you at risk of developing this unpleasant condition.
Signs and Symptoms
To start with the symptoms are mild and usually in the dominant hand. There may be a period of numbness or a tingling or burning sensation or pain generally in the thumb and the next two and a half fingers. It is likely to last only a short time and it may be eased through rubbing the hand or wriggling or shaking the wrist. Over time the symptoms worsen and persist for longer periods and it is common for both hands to be affected. They include;
- Discomfort or a dull ache in the hand and / or arm all the way up to the shoulder
- Burning / prickling sensation in hand – paraesthesia
- Numbness which may mean that it is difficult to feel what you are touching or be aware of temperature or pain, for example if you cut yourself
- Weakness usually starts with movements involving thumbs so actions such as gripping or fastening buttons are hard. Many people with CPS feel that they have become clumsy. Over time there may be visible wasting away of the muscles at the base of the thumb
- People complain that their hands look and feel different e.g. the skin colour may change and it may be drier than usual. Sometimes it can feel as if the hand is swollen even when it isn’t.
These feelings are often worse at night and may wake the sufferer.
The median nerve is very sensitive to pressure and the carpal tunnel is narrow so any slight decrease in the space available for the nerve is likely to cause problems. While there is not one specific cause there are a number of risk factors any one of which may be responsible. The causes may include arthritis of the wrist; injury to the wrist such as a fracture; hormonal changes such as during pregnancy or the menopause; medical conditions such as diabetes or an under-active thyroid; obesity; familial tendency – this may be just that small carpal tunnels run in families or simply regularly undertaking certain activities which involve repetitive wrist movements. This is an area we will look at later.
The first port of call is the GP who takes a medical history and examines the hand or hands. They will be looking for changes in the colour and texture of the skin and muscle wasting at the base of the thumb. They may flex a wrist for a minute to see if there is any tingling, burning, pain or numbness. Often this is sufficient to make a diagnosis but if there is doubt a nerve conduction study may be done.
If the symptoms are mild they may disappear with no treatment. If there is a clear cause such as arthritis, treating the underlying condition should help. Otherwise the options are as follows:
- Splinting the wrist may help to keep it straight and reduce pressure on the median nerve. Some people favour one splint at night and another one for the day when they are using the wrist more.
- Applying a cold compress to the wrist when the symptoms flare up
- Reducing any repetitive movements that may be the cause
- Pain killers such as Ibuprofen may help in the short term but do not offer a cure
- Steroid injection into the carpal tunnel often provides a period of relief
- Surgery – carpal tunnel release where the carpal ligament is cut to make more room in the carpal tunnel for the nerve.
Work activities related to Carpal Tunnel Syndrome
For some years there has been a widely held belief that working at a computer is one of the main causes of CTS. This has, however, been disproved through a study carried out at a Mayo Clinic in America. Here 257 people who worked on a computer up to 7 hours a day responded to a survey asking about sensations such as ‘pins and needle’ or numbness in the hands. Those who had symptoms indicative of CTS were investigated further through interviews, more questionnaires and finally they had a nerve conduction study done. Only 10.5% of all the participants had clinical symptoms of CTS and only 3.5% had this confirmed through the nerve conduction study. In other words there was no greater incidence amongst the computer workers than the general population. However, this should not mean that good ergonomic planning has no place in the office as other conditions and just general aches and pains are associated with poor ergonomics.
So what type of work has been linked to an increased incidence of CPS? A French study concluded that just being in work of any type raised the incidence from the non-working population. A recent meta-analysis of 37 studies concluded that using vibrating tools is associated with increasing the risk of developing CTS by five times and that high grip forces is another significant risk factor. Other studies have emphasised the role of repetitiveness in developing the condition.
If during work you are exposed to vibrating machinery, if you use high grip forces and / or if you move your hands repeatedly such as when cleaning or at an assembly line, there are some strategies you can employ to lessen the risk;
- Rest frequently
- Wear a splint to keep wrist still
- Wear fingerless gloves to keep your wrist warm
- Review the ergonomics of the workplace to see if there any improvements which could be made there
- See your GP to see about treatment
- See a physiotherapist to see if there exercises which may relieve it
With a bit of care and early intervention CTS may be managed and may disappear.