Left Untreated, Carpal Tunnel Syndrome Can Lead to Weakness in Fingers and Thumb

November 30, 2012 Dear Mayo Clinic: I've had symptoms of carpal tunnel syndrome for nearly a year, and it is starting to affect my work. How effective is treatment? What are the risks of not treating it? Will it continue to get worse, or does the damage level off at some point? Answer: Carpal tunnel syndrome is a condition that affects your hand and is caused by pressure on the median nerve in your wrist. If left untreated, carpal tunnel syndrome can lead to weakness and lack of coordination in your fingers and thumb. Treatment can relieve pressure on the nerve and, for most people, eliminate their symptoms. The carpal tunnel is a small passageway on the palm side of your wrist. Nine tendons and the median nerve travel through the carpal tunnel. The tendons control the movement of your fingers. The median nerve serves as a pathway for the sensations you feel in your palm, thumb, index finger, middle finger and outer border of your ring finger. It also sends nerve signals that move muscles around the base of your thumb. Carpal tunnel syndrome happens when the space in the carpal tunnel becomes smaller, resulting in pressure on the median nerve. In its early stages, symptoms may include intermittent tingling or numbness in your thumb, index finger, middle finger and outer border of your ring finger, along with aching in the palm. Many people wake up during the night due to numbness and tingling and have to shake the hand to ease those symptoms. As carpal tunnel syndrome progresses, you may feel you are losing coordinated movement of your fingers. You may notice weakness in your fingers that makes it hard to do daily tasks, such as buttoning buttons. Moving your thumb may also become difficult. Carpal tunnel syndrome is diagnosed based on an evaluation of your symptoms and a physical exam, followed by an electrophysiologic test. That test measures the electrical signals passing through the median nerve and how the muscles that are supplied by the nerve are being affected. It can show if the nerve is compressed. If you are diagnosed with carpal tunnel syndrome, a wrist splint is often the first step in treatment. A splint can be particularly helpful for people whose symptoms are bothering them at night. Wearing a splint during the night can keep the wrist from bending or being extended while you sleep. That often relieves the nerve pressure and eliminates nighttime discomfort. Wearing a splint during the day also can be useful if symptoms persist during waking hours. Some people don't like wearing a splint during the day, though, because moving the wrist naturally may be difficult. In addition to using a splint, a corticosteroid injection into the carpal tunnel may help reduce symptoms. Corticosteroids lower inflammation and swelling within the carpal tunnel, which can relieve pressure on the median nerve. Benefit may be temporary. For those whose symptoms return after an injection, surgery may be appropriate. The goal of carpal tunnel surgery is to relieve pressure on your median nerve by cutting the transverse carpal ligament that is pressing on the nerve. During surgery, the surgeon also checks to make sure that no other conditions are creating pressure on the nerve. For example, some people may have a cyst that extends into the carpal tunnel. For the majority of people who need carpal tunnel surgery, the procedure effectively resolves their symptoms. If you suspect you have carpal tunnel syndrome, see your doctor. If left untreated, the condition can disrupt your daily life. But effective treatments for carpal tunnel syndrome are available. — Sanjeev Kakar, M.D., Orthopedic Surgery, Mayo Clinic, Rochester, Minn.

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