The carpal tunnel is a channel through the wrist which carries the median nerve (which provides sensation from the thumb, forefinger, middle finger and a section of the ring finger). It shares the narrow tunnel space with a number of tendons. If there is any inflammation or swelling of these tendons, this can put pressure on the median nerve, which in turn causes pain (often at night time), numbness and tingling in the thumb and relevant fingers. The palm can also be affected and it is common to feel general weakness in the hand as a whole. The fingers and thumb may also feel swollen, even when they are not. In advanced cases it becomes difficult to grasp anything due to weakness of the thumb.
Causes
A number of things can cause, or contribute to carpal tunnel syndrome, for example…
- Repeated overuse of the wrist (from e.g. typing, working at a computer).
- Injury / trauma to the wrist.
- Arthritis in the wrist.
- Pregnancy (due to a buildup of fluid in the tissue in the wrist).
- Hormone disorder (such as acromegaly or hypothyroidism).
- Genetic factors - in some people the carpal tunnel may be narrower.
- Presence of a cyst or tumour in the carpal tunnel.
There are also a number of factors which increase the risk of developing carpal tunnel syndrome. These include…
- Smoking.
- Obesity.
- Diabetes.
- Age – the condition affects people aged 4-0-60 more than other age groups.
- Sex – women are three times more affected than men.
Carpal tunnel syndrome can also develop without any of the factors listed above being present at all.
Tests / Diagnosis
Diagnosis of the condition involves a thorough physical examination of the hands, arms, neck and shoulders and strength tests. Further tests, for example x-rays or a blood test, may be required to identify any possible cause of the condition. The main test is nerve conduction test and electromyography, although ultrasound or an MRI (magnetic resonance imaging) scan may be also needed to confirm the diagnosis and exclude other conditions.
Treatment
Carpal Tunnel Syndrome can be treated with:
- Addressing the underlying cause for carpal tunnel syndrome, such as avoiding overuse of the wrists, or correcting hormonal causes.
- Wrist splints may be beneficial to avoid bending of wrists, especially during the night.
- Surgery involves an incision to divide the fibrous band that is thickened within the carpal tunnel and causing compression of the median nerve. Surgery frees the median nerve and the symptoms of carpal tunnel syndrome may be reversible.