DEAR DR. DONOHUE: Please write something about hepatitis B. One of my best friends has it, and the doctor did not tell her to rest. She is pitiful-looking. I have been told it is the worst kind of hepatitis you can have. At one time she was as yellow as a pumpkin. – A.L.

ANSWER: I just wrote about hepatitis C. People are going to think I am obsessing about hepatitis, but it happens to be one of the most-asked-about topics in my mail.

All three kinds of hepatitis – A, B and C – cause liver-cell death. The initial infection with any of these viruses produces similar signs and symptoms. Not every infection gives rise to any symptoms. Sometimes they are silent. When symptoms arise, people lose their appetite and are constantly nauseated. They can develop joint and muscle pains. Body temperature usually rises. They might notice that their stools have turned gray and their urine has darkened. Then their skin and the whites of their eyes often turn yellow – jaundice. The initial infection can be so severe that it kills, but that is infrequent.

Bed rest is not mandatory during the infection, but physical activity is restricted.

Hepatitis B is bad but is far from being a death sentence. Nearly 95 percent to 99 percent recover completely. Between 1 percent and 5 percent develop a chronic liver infection. Less than 1 percent die.

Having a chronic infection means that the virus stays alive in the liver and continues to damage liver cells. The result can be liver cirrhosis, liver failure and death. Chronic infection can also lead to liver cancer.

The treatment picture for hepatitis B has brightened. There are five drugs now available for it — interferon, peginterferon, lamivudine, entecavir and adefovir. Sometimes a combination of these drugs is used.

There is a vaccine for hepatitis B. All infants get the vaccine. So should adults who are in jeopardy of catching it. Health-care workers are an example.

The hepatitis booklet gives the details of these three infections. Readers can order a copy by writing: Dr. Donohue — No. 503, 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: After a chest scan, my husband was told he had calcifications somewhere near the heart. His stress test was normal. What do calcifications outside the heart mean? – Anon.

ANSWER: Calcifications are the body’s Spackle. It uses calcium to patch up spots where cells have died or germs have landed. After inflammation or trauma, calcium is often laid down. The calcifications outside your husband’s heart are probably on his pericardium, the sac that holds the heart in place. They could be the coffins of dead germs that invaded the pericardium. In that case they are quite innocent.

Sometimes calcifications indicate more ominous things. Breast calcifications can be a cancer sign. The radiologist distinguishes cancerous calcifications from innocent calcifications by their size, their pattern and their shape. If your husband’s were dangerous, he would have been told that.

DEAR DR. DONOHUE: Can you inform me what myelodysplasia is? What causes it? What are its treatment and prognosis? – F.R.

ANSWER: “Myelo,” in this instance, refers to bone marrow. “Dysplasia” indicates faulty production of marrow cells. The marrow is where blood cells are made. “Myelodysplasia” should be “myelodysplasias” because it’s a group of related disorders in which the marrow isn’t turning out the required number of blood cells, usually red blood cells. Anemia, therefore, dominates the early stages of this illness.

Radiation, chemicals like benzene and some chemotherapy drugs can cause it. In most cases the cause is unknown, but it usually strikes older people, with the average age of onset being 68. Around 15,000 new cases are diagnosed each year in the United States.

Survival and prognosis depend on which variety of myelodysplasia a patient has. In some cases, it can be lethal within months. In other cases, it perks along for years. For some, chemotherapy, transfusions or both are given. A new drug, Vidaza, is available for some types of the illness.

For younger people, a stem-cell transplant obtained from bone marrow is the treatment of choice.

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.