DEAR DR. DONOHUE: Please tell me about pituitary tumors. Can they be treated? How? How long does a person who has one live? – F.Y.

ANSWER: The pituitary gland is a small gland about four-tenths of an inch (1 cm) long and wide. It has a big job. It controls all the other endocrine glands – thyroid, testes, ovaries and adrenal glands – by stimulating them with the hormones it makes.

Pituitary tumors cause trouble in two ways. If they are overproducing one of their hormones – say, the hormone that stimulates the adrenal gland – an abundance of adrenal-gland hormone leads to high blood pressure, osteoporosis, sometimes diabetes, and a redistribution of body fat.

Large pituitary tumors can create another problem by pressing on the optic nerves, which are in front of the gland. If the pressure is not relieved, blindness can result.

Decisions about treatment depend on what pituitary hormone is being excessively produced and on the size of the gland. Sometimes medicines can control the situation.

Many times, surgery is required. Often doctors can perform the surgery with instruments inserted through the nose. The gland is not far from the nose. This technique is called the transsphenoidal approach and is minimally traumatic. Sometimes radiation concentrated on the pituitary gland alone can be used. This is the gamma knife. People seldom die from a treated pituitary tumor.

DEAR DR. DONOHUE: My father has Parkinson’s disease. Are there any special diets for it? What is the life expectancy of someone with the illness? – R.H.

ANSWER: A well-balanced diet with plenty of fruits and fiber and adequate amounts of fluid is important for Parkinson’s patients. Such a diet prevents constipation, often a side effect of the illness. Most patients would also benefit from a multivitamin.

Some Parkinson’s patients have trouble swallowing food. They should eat a soft diet.

In the later stages of Parkinson’s, medicines might not work as well as they once did. A low-protein diet can sometimes improve the response to drugs. This is a matter your father’s doctor will discuss with you and him if and when it becomes necessary.

Many people with Parkinson’s disease live into their 80s. The illness, therefore, does not shorten all patients’ life spans.

DEAR DR. DONOHUE: I am 84. I have had hepatitis B for many years without any symptoms. Should I try to get rid of the virus with medication? – J.A.

ANSWER: You must ask your doctor if your blood tests show only a past infection or if they show a chronic infection, with the virus still living in the liver. Chronic infection with hepatitis B happens, but with much less frequency than it does with hepatitis C. You might not need medicine.

If you do have a chronic infection, then the decision to treat it is a joint one, made by your doctor and you. At younger ages, chronically infected hepatitis-B individuals are usually treated to prevent liver cirrhosis and the possibility of liver cancer. At 84, age plays a consideration in the decision. If your liver tests are normal, if you have no symptoms and if a liver biopsy shows no threatening changes, then the urgency for treatment is much less pressing.

DEAR DR. DONOHUE: What is the best – not the least-expensive – way to detect early pancreatic cancer? Two uncles on my mother’s side died of it. – B.B.

ANSWER: Helical contrast-enhanced CT scans and high-quality MRI scans are among the most sensitive tests for detecting pancreatic cancer. Such expensive tests are not necessary in many, many cases. Less-expensive tests like ultrasounds are also reliable.

Pancreatic cancer does run in families, but familial cases account for only 5 percent to 10 percent of all cases.

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.