Understanding Carpal Tunnel Syndrome

By Alejandro Badia, M.D.

Carpal Tunnel Syndrome is an extremely common as well as a very misunderstood condition.In recent years, it has received much coverage in the press but is still not completely understood even by the scientific community. The media has branded this condition as an occupational disease because of workers linking pain in their hands to repetitive activities such as typing or assembly line work.

Despite popular opinion, this condition is not caused by using a keyboard. However, if one has a predisposition to this condition, repetitive activity such as typing can aggravate it.

Carpal Tunnel Syndrome simply means that there is a compression of the median nerve in the hand. This nerve sits inside a tunnel in the hand whose floor and walls consist of bones known as carpal bones. The roof of this tunnel is a structure called the transverse carpal ligament. Besides the nerve, there are nine tendons which flex the fingers and thumb and run in the canal.

When lining around these tendons is inflamed, there is less space for the nerve and it becomes compressed. This compression of the median nerve leads to the symptoms of Carpal Tunnel Syndrome.

The symptoms most often reported with Carpal Tunnel Syndrome are numbness and tingling in the hand which often begins at night. Often there is also pain and weakness in the hand, particularly in the thumb. If allowed to progress for many years untreated, this could lead to atrophy of the muscles in the base of the thumb.

Besides the physical symptoms of Carpal Tunnel, the diagnosis is easily confirmed by a simple nerve conduction study. This measures the velocity and the latency of the nerve impulse across the median nerve at the wrist and can tell the physician if the patient has a compression of the median nerve. The condition most commonly occurs in middle-aged women, often perimenopausal. It can be caused by chronic conditions such as diabetes, gout or thyroid disease. It is also commonly seen in woman in their third trimester of pregnancy. When any of these other conditions are ruled out, the condition is labeled idiopathic meaning caused by an unknown process.

Carpal Tunnel Syndrome often coincides with related conditions such as tendonitis in the fingers, (trigger finger) of tendonitis in the wrist. DeQuervain's tendonitis, for example, leads to pain in the wrist at the base of the thumb.

The treatment for Carpal Tunnel is often directed at decreasing the inflammation of the tendons. Injections of steroids such as cortisone can lead to a decrease in the swelling. This will allow the median nerve more room in the carpal tunnel and relieve the pain. The most common treatment without the use of drugs or injections is a night splint. The splint does not allow the patient to flex their wrist at night which often occurs during dreaming. This relieves some of the pressure within the canal.