DEAR DR. DONOHUE: My daughter, 40 years old, died. The coroner, who is not a medical doctor, said she died of pulmonary edema, because her tongue and mouth had a white covering. My heart doctor told me it was congestive heart failure. Please tell me the difference between the two. – B.L.

ANSWER: You have my sincere sympathy on the death of your daughter at such a young age.

Pulmonary edema is a flooding of the lungs with fluid. Its causes are many. Pneumonia is one cause. Inhaling a toxic, irritating gas is another. Some medicines can cause it. Inflammation of the pancreas is often accompanied by pulmonary edema.

However, the biggest cause is congestive heart failure. The heart has become so weak that it cannot empty itself of blood. Blood backs up into the lungs. The fluid part of blood seeps out of blood vessels and fills the lungs’ air spaces with fluid – pulmonary edema.

The next question is: What causes congestive heart failure? Its causes are also many. A heart attack, out-of-control high blood pressure, heart valve problems and infections of the heart are a sample of possible causes.

I don’t understand the association the coroner made between a white-coated tongue and mouth and pulmonary edema.

The congestive heart failure booklet explains the causes of and the mechanisms involved in this common medical condition. Readers can order a copy by writing: Dr. Donohue – No. 103, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Will you tell me if an MRI and a CAT scan are the same? – P.B.

ANSWER: X-rays were the first invention that enabled doctors to look inside the body without having to cut it open. They were and still are one of medicine’s most valuable tools for making a diagnosis.

New techniques for exploring the body’s interior arose in the last part of the 20th century. CAT scans – computed axial tomography – yield pictures of inner anatomy with computer-generated views of internal structures gained from X-ray beams passed through a multitude of “slices” of the body. CAT has now become just CT scan. CT scans are excellent ways of imaging bones and bleeding in the brain, among other things.

MRI – magnetic resonance imaging – produces pictures of internal organs without any radiation. It employs powerful magnets to generate images. It’s especially valuable for delineating “soft” tissues like the scars that multiple sclerosis makes in the brain and spinal cord. Because of the magnetic fields engendered by it, MRI can’t be used for people who have metallic joints or implanted metallic devices.

Sound waves are used to capture pictures of internal organs too. They’re called sonograms or echograms. Echocardiograms, for example, give great pictures of the heart and its valves.

All these devices produce pictures of the body’s interior, but they do so in different ways, and they have different applications.

DEAR DR. DONOHUE: My heart wasn’t beating regularly. I didn’t sense that anything was wrong, but my doctor detected it and sent me to a heart doctor. She decided I should have an electric shock to get it beating normally. I did, and the shock worked – for one week. Then my heart started beating irregularly again. Now the heart doctor is going to use drugs. Why didn’t the shock work for me? – T.O.

ANSWER: The procedure is cardioversion, and your irregular heartbeat is probably atrial fibrillation, one of the most common heartbeat abnormalities. Cardioversion doesn’t work all the time. When atrial fibrillation is of recent onset, the chances for success with cardioversion are the greatest. Your heart doctor had no information on the duration of your fibrillation. You might have had it for quite some time without knowing it.

Medicines can sometimes convert atrial fib to a normal heartbeat. If they can’t, they can slow the beat to a level that’s not taxing the heart.

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