Most people think that CTS is caused only by repetitive hand or wrist movements, including those made by typists, carpenters, people who handle vibrating machinery, such as power tools, or supermarket checkout counter workers. But doctors now know that this painful ailment can have a variety of unexpected causes, which can make diagnosis tricky. About one million Americans are diagnosed annually with the condition.
CTS occurs when the median nerve, which runs down the forearm into the hand, becomes irritated. At the point where it passes through the wrist, this nerve is surrounded by a protective tunnel of bone and ligaments. If this area becomes inflamed or swollen, pressure on the nerve can cause the symptoms mentioned above.
Good news: Once CTS is diagnosed, pain-free hand function can usually be restored through a combination of rest and anti-inflammatory medication. And if that doesn’t work, a simple operation probably will.
THE MANY CAUSES OF CTS
Doctors now believe that CTS results from a combination of factors. Jobs or activities involving repetitive hand or wrist movements can help bring it on. But so can sleeping with your wrists bent inward 90 degrees or more (which decreases the size of the carpal tunnel passage). CTS also can result from medical conditions, including rheumatoid arthritis, hypothyroidism (low thyroid activity) and diabetes. Menopause and fluid retention from pregnancy may also give rise to symptoms.
CTS tends to run in families — most likely due to inherited wrist structure. Women are three times as likely as men to develop CTS, probably because their carpal tunnel passages tend to be smaller.
Many primary care doctors diagnose and treat CTS — so first ask your own doctor if he/she can handle your case. If not, your doctor can refer you to either a rheumatologist, neurologist or hand surgeon, all of whom treat CTS. (CTS is considered a neurological condition because it is brought about by impingement of the nerve by the bone and connective tissue.)
Most physicians begin by taking a complete medical history of the patient, which is important since this can determine if the condition is caused by an underlying ailment, such as arthritis or diabetes, or a different kind of nerve impingement. If the patient complains of achiness, tingling, burning or numbness in one hand or pain extending out from one wrist, CTS is strongly suspected — particularly if pain occurs at night, a common symptom. Signs that it is not CTS include symptoms that occur in both hands, which may indicate rheumatoid arthritis or hypothyroidism. In this case, an evaluation for rheumatoid arthritis and thyroid blood test are in order. (Persistent numbness or tingling in the hands can also be a sign of nerve damage due to long-standing diabetes.)
Or, it could be damage to a different nerve, especially if the pinky or non-thumb side of the ring finger is involved (since that is a sign of cubital tunnel syndrome, in which the ulnar nerve, which runs from the collarbone through the inside of the elbow and forearm to the pinky, is entrapped).
Diagnostic tests usually include a physical exam to determine the location of the pain — these may consist of testing the feeling and strength in the fingers and hand… tapping the underside of the wrist… or placing the backs of both hands together. The physician also will want to rule out the possibility of other muscle or nerve disorders, including muscular dystrophy, peripheral neuropathy or nerve lesions (any nerve injury). To do this, he will perform a nerve conduction study, in which a computerized system measures the amount of electricity that is being conducted along the nerve, something a physical exam can’t pick up. An underlying nerve disorder will show a reduction in nerve transmission different from that of a compression injury like carpal tunnel syndrome.
Another type of test is an electromyogram, in which small needles are used to measure electrical activity in the muscles of the hand and wrist. If these tests are inconclusive, you may be referred to a neurologist for a complete neuroelectrical exam. Nerve testing is not always accurate and depends on the expertise of the doctor performing the test.
When CTS is caused by another condition, such as diabetes or arthritis, treating the condition may alleviate CTS. Treatment might also involve taking pressure off the affected area by resting it, stopping any activities that may contribute to the symptoms and placing the wrist in a splint to hold it in a neutral position, maximizing the space inside the carpal tunnel.
A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen (Advil, Motrin) or naproxen (Aleve, Naprosyn), is typically prescribed as well. (Consult your doctor about how much is safe for you to take.)
Applying a cold pack to the affected area may also help temporarily relieve symptoms. If pain persists, your doctor may suggest injecting the steroid cortisone into the wrist to further reduce inflammation. Alternative treatments, such as acupuncture, have not been clinically proven to be effective.
With these treatments, most people begin feeling better within a week. However, in severe cases, CTS may continue to interfere with daily activities… or pain and numbness may persist for six months or more. A carpal tunnel release operation by a hand surgeon or neurosurgeon may then be required. In this procedure, which is currently performed on about 577,000 Americans annually, the ligament pressing on the median nerve is cut. The procedure may be done laparoscopically, a minimally invasive procedure in which a thin tube containing a camera is inserted through a small incision in the wrist, or it may be done through an open incision at the base of the palm. Both surgeries are performed under local anesthesia, and the patient goes home the same day. Full recovery generally takes six to 12 weeks and may include physical therapy. While a small number of patients report some lingering pain, numbness or weakness, 70% of patients are satisfied with the results of their surgery.
PREVENTING A RECURRENCE
If CTS is caused by an underlying condition, such as diabetes, it’s important to keep that condition under control. Some people also need to avoid or modify activities that may have contributed to the symptoms in order to help prevent a recurrence. This may include giving up or cutting back on certain hobbies and activities that put stress on your wrists and hands… and evaluating your position when you use a computer at a desk.
Example: Make sure that your chair and desk are at the right height. Your chair should be adjusted so that your feet are flat on the floor and your elbows are at or above keyboard height when your arms hang naturally. Some people with CTS are helped by a keyboard wrist support that maintains a neutral position for the wrists.