The symptoms of carpal tunnel syndrome are caused by compression or irritation of a nerve. The median nerve crosses the palm side of your wrist and goes through a tunnel to reach your fingers and some of the muscles in your hand. This is one of a group of syndromes called compressive neuropathies. It is common not to know the exact cause of carpal tunnel syndrome.
The most common symptom of carpal tunnel syndrome is numbness. The thumb, index, and middle fingers are commonly affected but some people have symptoms in all the fingers. Waking up at night with the feeling that your hand has "fallen asleep" is very common. The nerve compression can also cause pain. The numbness may be occasional or constant. As the syndrome progresses, muscles in the hand may be affected.
Other common symptoms are:
Carpal tunnel syndrome is suspected when the above symptoms are present and the physical examination supports the diagnosis. Common examination findings are numbness in the fingers in a specific pattern, signs of irritation of the median nerve, and weakness or atrophy (a decrease in size of a muscle) of certain hand muscles.
A test called a nerve conduction study is frequently used to confirm the diagnosis. This test measures how fast the median nerve carries information. In carpal tunnel, the test often shows that the nerve carries information more slowly (an indication that the nerve is compressed).
Numbness and weakness can also be caused by nerve compression in the neck (sometimes described as having a "pinched nerve"). Therefore your doctor may ask about neck symptoms or order tests to evaluate this.
The goal of treatment in carpal tunnel syndrome is to decrease compression and irritation of the nerve such that the symptoms resolve. Using a splint to stabilize the wrist is a common start. This may be most useful at night. Keeping the wrist from bending excessively forwards or backwards during the night decreases pressure on the nerve. An injection of corticosteroid, to decrease inflammation, into the carpal tunnel may also be used. This treatment usually decreases symptoms, though, the relief may be temporary.
If symptoms persist and do not respond to other treatment methods, surgery may be recommended. The purpose of surgery is to decrease pressure on the nerve by increasing the size of the carpal tunnel. This is an outpatient procedure. It does not always require general anesthesia. You and your doctor will discuss the best option for you. An incision is made in the palm and a ligament over the nerve is divided. The incision is covered for about two weeks and then sutures are removed. Activity then progresses as symptoms decrease. Full recovery takes about six weeks.