DEAR DR. DONOHUE: I would like some information on carpal-tunnel syndrome. I hope you can enlighten me. – L.B.

ANSWER: “Carpus” is the Latin word for wrist. The carpal tunnel is a true tunnel whose sides and bottom are the wrist bones and whose ceiling is a dense ligament band. One of the structures that pass through the tunnel on their way to the hand and fingers is a large nerve that supplies the thumb, index, middle and half of the ring finger. Carpal-tunnel syndrome results when something compresses that nerve as it runs through the tunnel.

The fingers served by the nerve tingle or become numb. They can become quite painful. Sometimes the pain shoots up into the forearm. The pain of carpal-tunnel syndrome predictably worsens at night. If the condition progresses, there can be weakness of the involved fingers.

Repetitive use of the tendons that also run through the tunnel can cause them to swell and compress the nerve. Pregnancy can cause swelling in the tunnel and nerve compression. Trauma is another cause. Diabetes and rheumatoid arthritis are associated with the syndrome. Frequently, however, a cause is not identified.

Simply resting the wrist can lessen tunnel inflammation and let the nerve recover. That can be accomplished by wearing a wrist splint, obtainable in most drugstores. Some people get relief by wearing it only at night. Anti-inflammatory medicines – ibuprofen being an example – can also alleviate inflammation and nerve compression. If these measures fail, the doctor can inject cortisone, which almost always calms inflammation. In only a few instances is surgery necessary to free the nerve from whatever is pressing on it.

DEAR DR. DONOHUE: Please tell me the foods to avoid in order to lower triglycerides. I had my test done late in the afternoon after a large lunch. My cholesterol is fine. I have a thin chocolate mint after dinner. – P.W.

ANSWER: Triglycerides are the stuff fat is made of. A high blood triglyceride level can contribute to artery clogging, heart attacks and strokes.

A low-fat diet, including avoiding fried foods, lowers triglycerides. So does weight loss, even a modest amount. Sugars contribute to triglyceride elevation, so they should be limited. Fruits and starches don’t have to be completely crossed off the diet, but their amounts should be reduced. Alcohol ought to be used only in moderation. The omega-3 fatty acids of fish bring triglyceride numbers down.

If the reading is truly high and if your doctor feels it’s a danger, medicines can also reduce the level.

You might be worrying about nothing. Triglyceride numbers are valid only after a 12-hour fast. Having your blood tested after a large lunch is bound to give false values. Have the test repeated after you have fasted for 12 hours. You might not have to change a thing in your diet.

Even if your numbers are high, the thin chocolate mint after dinner isn’t going to kill you. Please pass me one.

DEAR DR. DONOHUE: I have another suggestion for your list of causes of chronic cough. I went 20 years undiagnosed with a chronic cough. Finally a wise, young doctor picked up on my symptoms and had me get a bronchogram. It was found that I had bronchiectasis. I had my left lower lung lobe removed, and I have been fine ever since. – M.H.

ANSWER: Bronchiectasis (BRAWN-key-EK-tuh-siss) is a permanent dilation of the cartilage wall of airways – bronchi. The dilation comes from a destructive inflammation of the wall, something that often follows a severe bronchial infection or pneumonia. The dilated airways fill with pus. Bronchiectasis is still with us, but not to the extent it was in the days before antibiotics.

Its hallmark symptom is a persistent or recurrent cough that brings up thick, yellow sputum.

Chest X-rays can sometimes show it. The latest test is a CT scan. Before scans, bronchograms, where a thin layer of opaque dye trickles into the airways, showed their destruction.

If bronchiectasis is limited to a specific and small section of lung, the involved section can be removed. Otherwise, measures like postural drainage and antibiotics at the first signs of infection are its treatment.

DEAR DR. DONOHUE: I have been diagnosed with type 2 diabetes and am taking time-release glipizide. Why is it that I go to bed with a good reading but wake up with a high reading, and I haven’t drunk or eaten anything since 3 p.m.? – J.W.

ANSWER: A time-release or controlled-release medicine is one that’s been formulated to maintain effective blood levels for a long time period – in some cases, a full day, like your medicine. Usually such medicines work well, but they don’t work for 100 percent of the population 100 percent of the time.

Toward the end of 24 hours, your blood levels of medicine might be dipping too low to promote enough insulin secretion to maintain normal blood sugar.

What to do depends on how high your readings are.

A higher dose of medicine might be all you need. If you’re taking the highest dose and your blood sugar is too high, then you might have to take a different medicine, or you might have to take a non-time-released preparation of your current medicine but take it more often.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.