Carpal tunnel syndrome

The carpal tunnel is the narrow space formed by the bones of the wrist (carpal bones) and the strong ligament that lies over them. In carpal tunnel syndrome, the median nerve, which controls some hand muscles and conveys sensation from nerve endings in part of the hand, is compressed where it passes through the tunnel. This compression causes painful tingling in the hand, wrist, and forearm. Carpal tunnel syndrome is a common disorder, especially in women aged 40-60, and often affects both hands.

What are the causes?

In some cases, the underlying cause of nerve compression is not known. In others, it occurs because the soft tissue within the carpal tunnel swell, compressing the median nerve at the wrist. Such swelling may be due to diabetes mellitus, or it may occur during pregnancy. The carpal tunnel may also be narrowed by a joint disorder, such as rheumatoid arthritis, or by a wrist fracture. The syndrome is associated with work that involves repetitive hand movements, such as typing, which can result in inflammation of the tendons in the wrist.



What are the symptoms?

Symptoms mainly affect specific areas of the hand, such as thumb, the first and middle fingers, and the palm of the hand. Initially, symptoms may include:

- Burning and tingling in the hand.
- Pain in the wrist and up the forearm.

As the condition worsens, other symptoms may gradually appear including:

- Numbness of the hand.
- Weakened grip.
- Wasting of some hand muscles, particularly at the base of the thumb.

Symptoms may be more severe at night, and pain may interrupt sleep. Shaking the affected arm may temporarily relieve symptoms, but the numbness may become persistent if left untreated.

What might be done?

Your doctor may suspect carpal tunnel syndrome from your symptoms. He or she will examine your wrists and hands may tap the inside of your wrists to check if a tingling sensation occurs. Nerve conduction studies may be carried out to confirm the diagnosis. If pregnancy is the cause of carpal tunnel syndrome, the symptoms usually disappear after childbirth. In other cases, treating the cause, if it can be identified, usually relieves symptoms.

The symptoms of carpal tunnel syndrome may be relieved temporarily by nonsteroidal anti-inflammaroty drugs or by wearing a wrist splint, particularly at night. In some cases, a corticosteroid injection under or around the ligament may reduce swelling. If symptoms persist or recur, you may have surgery under local anaesthesia to cut the ligament and release pressure on the nerve. After surgery, there are usually no further symptoms.