Carpal Tunnel Syndrome occurs when the median nerve that runs from the forearm through the wrist and into the hand becomes pressed or squeezed within the wrist compartment. Carpal Tunnel Syndrome is responsible for hours of lost work in the United States among specific job categories.
The median nerve, that runs through the wrist compartment controls the sensation to the palm side of the thumb and the first three fingers but not the last pinkie finger. Patients with Carpal Tunnel Syndrome often complain that their fingers feel swollen even though there is no apparent swelling to the joints or fingers. There is however, pain, weakness or numbness in the hand and wrist, which radiates up the arm.
Carpal Tunnel Syndrome is a form of entrapment neuropathy. Neuropathy is a fancy way of saying that there is nerve involvement and often nerve pain that is difficult to control.
The carpal tunnel is a narrow rigid passageway of ligaments and bones at the base of the hand. This is where the tendons, ligaments and nerves pass through the wrist and expand to the hand. Compression happens when the area becomes irritated and there is swelling squeezing both the nerve and the tendons.
Symptoms start gradually. Patients feel burning, tingling, itching and numbness in the palm of the hand and first three fingers. Symptoms appear in one or both hands at night. People may wake up feeling the need to “shake out” their hands. Patients report that their grip strength is decreased and they find it difficult to make a fist, grasp objects or perform fine motor tasks (those tasks that require fine finger control).
If Carpal Tunnel Syndrome is left untreated the muscles as the base of the thumb will atrophy or become smaller. Carpal Tunnel Syndrome is often the result of repetitive motions and a combination of pressure on the nerve from swelling. There can be a congenital predisposition to a smaller tunnel in the wrist and some believe that women are more prone because their wrists are smaller. However their tendons, ligaments and muscles are also smaller.
Other factors that cause Carpal Tunnel Syndrome are injury, over activity of the pituitary gland; hypothyroidism, rheumatoid arthritis, mechanical problems, work stress, fluid retention or the development of a cyst in the tunnel. Women are three times more likely to develop carpal tunnel. The dominant hand is affected first and produces the most severe pain.
The risk is higher in people performing assembly line work – manufacturing, finishing, cleaning, and meat packing. However in a 2001 study by the Mayo Clinic researchers found that heavy computer use (up to 7 hours per day) did not increase a risk of carpal tunnel.
Early diagnosis and treatment are important to avoid permanent damage to the median nerve. A physical exam of the hands, arms, shoulders, and neck can help determine if the complaints are related to daily activities or to an underlying disorder; and can rule out other painful conditions.
Each finger should be tested for sensation, and the muscles at the base of the hand for strength and signs of atrophy. The diagnosis is confirmed with electrodiagnositics. A nerve conduction test is performed to evaluate the function of the nerves. A small electric shocks are applied and the speed the nerve transmits the impulses is measured. With Carpal Tunnel Syndrome the speed is decreased. An MRI can show the anatomy of the wrist but this isn’t especially useful in diagnosis of Carpal Tunnel Syndrome. Ultrasound imaging can show impaired movement of the nerve.
Carpal Tunnel Syndrome is common and not without it’s disadvantages. The best specific treatment is to rest the muscles, tendons and hand from the repetitive motion that cause the problem in the first place and once the condition has been resolved it is important not to return to your previous habits.