Carpal tunnel syndrome is characterised by numbness, tingling and pain in the thumb and fingers of one or both hands.The carpal tunnel is a narrow space at the front of the wrist, through which pass the tendons that bend the fingers and wrist. This space is roofed over by a tough ligament that prevents the tendons from pulling away from the wrist when it is bent.

One of the two nerves that allow feeling in the hand, the median nerve, also passes through the carpal tunnel, and there is little or no room for expansion. Any swelling in the region, from any cause, tends to compress the median nerve and interfere with nerve impulses.

Carpal tunnel syndrome may be associated with occupational heavy use of the wrist and injury brought on by prolonged use and strain of the wrist eg typing.

However, sometimes the problem is caused by other conditions such as:

• a thickening of the overlying ligament, as in rheumatoid arthritis;
• to body overgrowth because of an excess of growth hormone from the pituitary gland (acromegaly);
• swelling due to diabetes mellitus;
• joint fracture;
• inflammation of wrist tendons;
• an underactive thyroid gland (myxoedema);
• pregnancy (usually disappears after childbirth).

Treatment

The use of a splint and rest for several weeks may alleviate the symptoms.

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen may help to reduce swelling and inflammation.

Failing this, relief of symptoms may be obtained by an injection of a corticosteroid drug into the carpal tunnel. This is highly effective against inflammation and reduces swelling.

When all else fails, the syndrome may be relieved by a surgical operation to cut the ligament overlying the tunnel.