Alejandro Badia, MD, FACS
Carpal Tunnel Syndrome is a very common and poorly understood condition; so much so that in recent years it has received a lot of media attention, yet even the scientific community doesn’t fully understand it. The media often classifies it as an “occupational disease” (since they tend to associate it with repetitive activities like typing or assembly line work in a factory, as the pain manifests in the hands). However, public opinion is mistaken, and the reality is different: the cause is not keyboard use. While there is some predisposition to this condition, repetitive activities (like typing) can aggravate it.
“Carpal Tunnel Syndrome” means that there is compression of the median nerve in the hand. This nerve is located within a tunnel whose lower and lateral walls are formed by the carpal bones (the upper wall is formed by a structure called the transverse carpal ligament).
In addition to the nerve, there are nine tendons that flex the fingers and line the carpal tunnel. When the membrane covering these tendons becomes inflamed, the reduced space causes nerve compression, and this “median nerve compression” is what produces the symptoms of Carpal Tunnel Syndrome.
The most common symptoms associated with Carpal Tunnel Syndrome are numbness and tingling in the hand (which usually begins at night). Pain and weakness in the hand, especially the thumb, are also common, and if left untreated for a long time, the muscle at the base of the thumb can atrophy. Besides the physical symptoms of Carpal Tunnel Syndrome, the diagnosis can be easily confirmed with a nerve conduction study, which measures the speed and latency of nerve impulses through the median nerve in the wrist and helps the doctor determine if the patient is suffering from median nerve compression.
The condition is more common in middle-aged women (often perimenopausal) and can be caused by chronic conditions such as diabetes, gout, or thyroid disease. It is also common in women during the third trimester of pregnancy. If the person has no known history of these conditions, the cause is considered idiopathic: caused by an unknown process.
Carpal Tunnel Syndrome is related to conditions such as tendonitis in the fingers, trigger finger, or tendonitis in the wrist (De Quervain’s tenosynovitis, for example, causes pain in the wrist at the base of the thumb).
Treatment for Carpal Tunnel Syndrome often focuses on reducing inflammation of the tendons (steroid injections such as cortisone can help reduce inflammation), thus giving the median nerve more space in the carpal tunnel and thereby reducing pain.
The most common non-drug treatment (without the dreaded injections) is splinting the hand at night, preventing wrist movement during sleep. Symptoms worsen at night because the hand is at the same level as the heart, leading to fluid buildup in the soft tissues within the carpal tunnel. This is compounded by complex hormonal changes that can increase fluid retention overnight. (As a remedy, some researchers believe that a high dose of vitamin B-6 may act as a diuretic, reducing fluid in the carpal tunnel and relieving symptoms.)
