Do you think you might have carpal tunnel syndrome? If you have diabetes, your assumption is more likely to be correct, because carpal tunnel syndrome is fifteen times more common in people with diabetes than in the general population.
Experts used to think that you got carpal tunnel syndrome simply from too much computer keyboarding, but that idea is fairly discredited these days.
Instead, carpal tunnel is primarily associated with medical conditions such as diabetes, osteoarthritis, hypothyroidism, and rheumatoid arthritis; it’s also linked to obesity, smoking, alcohol abuse, and mental stress, as well as genetic factors.
Carpal tunnel syndrome is called an entrapment neuropathy because the median nerve is entrapped and compressed in the carpal tunnel.
The carpal tunnel is a narrow, rigid tunnel at the base of the hand, made from an arched roof of ligament that tops a U-shaped cluster of eight bones. The median nerve runs from the forearm through the tunnel and into the hand, in company with some tendons. If the tendons become thickened or other swelling makes the tunnel too narrow, pressure is put on the median nerve at the wrist.
Because the median nerve controls sensations and movement on the palm side of the thumb and first three fingers, that pressure can cause pain, weakness, or numbness in the hand and wrist, and sometimes up the arm as well. It’s akin to the mechanism that makes your leg go to sleep after you’ve sat for awhile in a position that puts pressure on your leg nerves.
The exact cause of the swelling usually isn’t known. Women are three times more susceptible to carpal tunnel syndrome than men are, because their carpal tunnel is often narrower in the first place. Carpal tunnel syndrome is associated with temporary swelling due to fluid retention during pregnancy. Diabetes also plays a big role. Carpal tunnel syndrome has been reported in up to twenty percent of people with diabetes.
Conversely, diabetes is more likely in people with carpal tunnel syndrome. In one study, researchers found that people who had been diagnosed with carpal tunnel syndrome were 36 percent more likely to later be diagnosed with diabetes, regardless of other diabetes risk factors.
The diabetes link is possibly due to the fact that when blood glucose levels are high, the proteins in the tendons of the carpal tunnel become glycosylated; that is, glucose attaches to the tendon proteins, inflaming them and forming a sort of biological superglue that makes the tendons less able to slide freely. If you’re susceptible to carpal tunnel syndrome because of diabetes or other conditions, the condition may be brought out or exacerbated by repeated forceful flexing of your hands and wrists.
So how do you know if you have carpal tunnel? Often you’ll feel a “pins and needles” tingling. You may have a burning feeling or a loss of sensation in the areas of the hand that are served by the median nerve, so that you feel as if your hand has gone to sleep. You may also experience pain going up into your forearm, and sometimes your grip might be weaker. You may be awakened by the pain at night, especially if you sleep with your wrists bent, because the condition can be aggravated by curling or flexing your wrist.
There are a number of tests that you or your doctor may conduct to diagnose carpal tunnel syndrome. A simple at-home assessment is called the “flick” test: you’re likely to have carpal tunnel if, when your symptoms are worse, you shake and jiggle your hands as if you were shaking a thermometer. Your doctor may try to elicit a diagnostic response called Tinels’ sign by tapping on top of your median nerve on the palm side of your wrist.
The test is positive for carpal tunnel syndrome if it produces a tingling or shocklike sensation, but it doesn’t always work. Another diagnostic tool is Phalen’s test, in which you rest your elbows on a table, then let your wrists dangle so your hands are pointing down with your palms pressed together in the prayer position.
If your fingers tingle or feel numb within a minute, that’s a sign of carpal tunnel syndrome. Your doctor can also look for weakness or atrophy in your hand muscles, but once that’s happened it’s a little late in the game, so you should try to get help before it occurs.
Diagnosis of carpal tunnel syndrome in people with diabetes is sometimes complicated by the fact that they have tingling, prickling, or numbness due to underlying peripheral neuropathy that’s unrelated to carpal tunnel syndrome.
Doctors can sometimes differentiate between the two by doing a nerve conduction study. To perform a nerve conduction study, electrodes are fastened to your hand and wrist, from which small electric shocks are sent through the nerves in the fingers, wrist, and forearm. The speed of the signal is then measured. Healthy nerves can conduct electricity at 120 miles per hour, but carpal tunnel damage slows things down. Often in diabetic patients, however, these tests don’t work that well; consequently, your doctor will need to take all your circumstances into consideration in making his diagnosis.
Once you’ve been diagnosed, what can you do to make it better? Resting your affected hand and wrist is helpful, as is wearing a splint that prevents your wrist from flexing and extending, especially at night. You might be given a short course of non-steroidal anti-inflammatory drugs like aspirin or Tylenol. If they don’t work, you can try injections of cortisone (steroids) into your wrist to reduce swelling. Injections are variably effective: they’re most successful in mild to moderate cases that result from a flare-up, and often they don’t help for longer than a month.
Some studies show that vitamin B6 (pyridoxine) supplements, a hundred milligrams a day, may ease the symptoms of carpal tunnel syndrome. A dose of 500 milligrams of inositol twice daily has also been recommended. Acupuncture and chiropractic care have helped some people, though their effectiveness hasn’t been proven in formal trials. Yoga has also been shown to reduce pain and improve grip strength.
If none of those measures work and your symptoms have lasted longer than six months, you may consider surgery. Carpal tunnel release is among the most common surgical procedures in the United States. The surgery creates more space for your median nerve by cutting the ligament that forms the roof of the carpal tunnel, thus relieving pressure on the nerve. It’s generally done using local anesthesia and doesn’t require an overnight hospital stay. Although it’s not a surefire fix, it often relieves symptoms right off the bat, and eighty to ninety percent of people who’ve undergone the surgery are still doing fine even six months later.
If you leave your carpal tunnel syndrome untreated, you may end up with atrophied thumb muscles or other unpleasant consequences of nerve damage. Whether or not you consider your carpal tunnel symptoms to be just annoying or downright disabling, it’s important to get yourself to the doctor and have yourself checked out if you suspect carpal tunnel syndrome.