DEAR DR. DONOHUE: When I had an auto accident, I was thrown against the steering wheel. I didn’t hit the steering wheel very hard. However, I was taken to the emergency room, and chest X-rays were taken. Nothing was broken. They gave me a copy of the report. It says my heart is slightly enlarged. No one told me to do anything about it. Should I? – R.M.

ANSWER: You should at least have your doctor review the report.

Hearts grow larger for good and bad reasons. The heart is a muscle, so athletes often have slightly larger-than-normal hearts. The heart responds to exercise in the same way any other muscle does: It grows.

In the bad category of heart enlargement is a heart grown large due to high blood pressure. Heart muscle has to thicken in order to pump blood with more force in the face of elevated artery pressure. If the process is not relieved, then the enlarging heart is doomed to fail. Overworking a horse leads to the same end.

Hearts can enlarge due to heart muscle weakness. A heart with a deficient supply of blood becomes flabby. Blood that flows into it makes it balloon. Soon there is a heart filled with blood that looks like an overstuffed pillow. This is the kind of heart seen in congestive heart failure. The flabby heart cannot pump blood vigorously, so blood backs up into the lungs and congests them. Breathing becomes labored. There are many ways to remedy this situation. Some entail taking medicine. Some entail opening up blocked heart arteries with a balloon or through surgery.

Inherited cardiomyopathy is another condition that can be a cause of enlarged hearts. Cardiomyopathy – of which there are several kinds – is a heart illness involving only heart muscle.

Viral infections of the heart can cause it to dilate.

I have given you enough reasons for you to take your X-ray report to your doctor for clarification.

DEAR DR. DONOHUE: I had been in the habit of taking a daily laxative. I knew it was wrong, but without one I would become terribly constipated. Then I discovered prunes. I stopped taking the laxatives and now take prunes every day. Is there any danger in taking prunes every day? – C.D.

ANSWER: Prunes have been renamed “dried plums.” What makes them such good promoters of regularity is the subject of debate. Some say it’s because they are a good source of fiber, and fiber, holding on to water, keeps undigested food moist as it passes through the digestive tract. Others claim that it is the sorbitol in prunes that has a laxative effect. Sorbitol is classified as a sugar alcohol, although it is neither sugar nor alcohol. It does impart sweetness, and it has a laxative effect. Then there is a group that doesn’t subscribe to either of these explanations. These people say there is an as-yet-unidentified substance in dried plums that makes them effective in combating constipation.

You are not going to overdose on dried plums. Eight is the usually recommended daily amount.

The entire population seems to be at war with constipation. The pamphlet on constipation and laxatives can furnish information that can help people win that war. To obtain a copy, write to: Dr. Donohue – No. 504, P.O. Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I am a new mother, and my baby has thrush. What is it? Does it happen only to babies? She’s on medicine now, and I wonder how effective it is. – B.L.

ANSWER: Thrush is an infection with the candida yeast, and the illness is more properly called candidiasis (CAN-duh-DIE-uh-suss). Babies pick up the yeast as they pass through the birth canal. It can take some time before it shows itself as a mouth and tongue covered with a white blanket.

Adults get it, too. Often they come down with the yeast when they take antibiotics, which kill off good mouth germs that keep the growth of candida in check.

Medicines for it are quite effective.

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.