DEAR DR. DONOHUE: Before going to camp, my son had to have a physical exam. The only doctor who had examined him before this exam was his pediatrician, and that was 13 years ago. The new doctor told us he has a heart murmur that needs further investigation. How serious is this? – W.A.

ANSWER: Heart murmurs conjure up worries that often are not justified. A murmur is a whooshing sound heard between heartbeats. Often, by listening with the stethoscope, the doctor can determine if a murmur is an indication of trouble or not.

Many murmurs are innocent sounds. Children who are on the thin side often have innocent murmurs. There is little padding between the doctor’s stethoscope and the heart. Noises that would not be heard in someone with a larger chest can be heard in a lean child. Murmurs resulting from innocent causes are called functional murmurs.

Murmurs that result from structural changes in the heart often have such distinctive sounds that a definite diagnosis can be made on the spot. Structural changes are heart valve changes or holes in the partition that divides the heart into right and left sides.

When rheumatic fever was rampant, one of its most feared consequence was heart valve damage. That damage always produced a murmur. Now, with fewer cases of rheumatic fever, the incidence of murmurs has fallen.

When the doctor cannot tell the nature of a murmur, then ultrasound pictures can. Ultrasound pictures are also known as echocardiograms. The ultrasound exam is painless, quick and uses no radiation. I am interested in the results of your boy’s ultrasound. I believe it will not disclose trouble, since his pediatrician did not hear a murmur 13 years ago.

The entire spectrum of heart valve problems and murmurs is covered in the valvular heart disease pamphlet. Readers can obtain a copy by writing: Dr. Donohue – No. 105, 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 have some slightly tender bumps in my groin. If I don’t press them, they don’t hurt. If I do, they hurt. What are they? – B.R.

ANSWER: A safe bet is they are lymph nodes. Hundreds of lymph nodes are positioned throughout the body. They filter germs or any foreign substance that has found its way into the body.

The “groin” is territory most people have only a vague notion of. It’s the crease where the thigh meets the lower abdomen.

The groin has a large number of lymph nodes that filter foot and leg invaders. The feet and legs are constantly under attack from germs that gain entrance through unnoticed breaches in the skin. Athlete’s foot, a prevalent affliction, is a condition that fosters entrance of germs into the feet and legs and eventually to groin nodes.

Enlarged groin lymph nodes are a common finding.

Not to unsettle you, but large nodes can have much more sinister causes. Lymph node cancer is one of them. Check your groin nodes for the next two weeks. If they have not shrunk by then, you need a doctor’s evaluation of them.

DEAR DR. DONOHUE: We have a grandson who is 18 and who has eaten nothing but carbohydrates for almost a year. He eats tossed salads without dressing, steamed veggies, cereal and toasted bagels with nothing on them. He will be going to college in August, and we will have no way to monitor what he is eating. How will this diet affect his health? – N.C.

ANSWER: Your grandson sounds like he is trying to follow a vegetarian diet without knowing what he is doing. In addition to carbohydrates, a vegetarian diet provides protein and a bit of fat, but a person must have a solid grounding in what constitutes a healthy vegetarian diet.

We need protein, fat, minerals, vitamins and even some cholesterol. If the boy is exceedingly thin now, then I would advise a visit to the family doctor. If he’s of average weight, I would advise a visit to a dietitian to teach him sound nutritional principles.

DEAR DR. DONOHUE: I recently had my yearly mammogram. It was found to be abnormal. The doctor said I should have a biopsy as soon as possible. I had the biopsy done two weeks later. I don’t know why it had to be done so fast. I know other women who wait six months for a repeat mammogram before they have a biopsy. Maybe you could explain why and explain the biopsy report. – J.C.

ANSWER: Calcifications show up on many mammograms. The size, the distribution, the location and the pattern of calcifications are factors the radiologist (radiologists read X-rays and scans) takes into account in deciding whether calcifications are innocent or suggest cancer.

Often it is difficult to make a definite decision. If most of the mammographic factors favor cancer, then a biopsy is done soon. If a tally of indicators falls only a little short of proclaiming the calcifications as innocent, then it is safe to wait for a second mammogram some time later. If the second mammogram looks exactly like the first one, a biopsy is often not needed.

Your report showed “fibrocystic” changes with microcalcifications. There is no suggestion of cancer. The breast lump was harmless.

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.