DEAR DR. DONOHUE: My wife, 80, has been diagnosed with dementia. I am 84 and have been caring for her for almost a year. I’m wondering what could develop. – R.V.

DEAR DR. DONOHUE: Five years ago, my 93-year-old mother died in a nursing home. Her death certificate listed “end stage dementia” as the immediate cause of death. Will you explain how dementia causes death? – C.R.

ANSWER: The word “dementia” is a source of much misunderstanding. It means a deterioration of thinking, of memory, of the ability to express oneself, of the capacity to perform simple functions like balancing a checkbook, and of learning any new information. Mental power dwindles to such an extent that the tasks of daily living – dressing, bathing, eating – are impossible to carry out.

Under the general heading of “dementia” are many different illnesses. The most prevalent kind of dementia is Alzheimer’s disease. Other forms include such things as multiple small strokes, Lewy body disease, frontotemporal degeneration and many more. Each of these dementias has some distinctive signs, but they all feature a decline in mental performance.

Dementias do not cause death by themselves. However, they take a toll on the body. People with dementia die from infections like pneumonia, from lung blood clots, from heart attacks, from kidney failure and from a wasting away of the body because demented people cannot maintain nutrition.

On average, people with Alzheimer’s dementia live from two years to a decade or longer after the diagnosis is made.

DEAR DR. DONOHUE: I have been diagnosed with a type of vasculitis called Henoch-Schonlein purpura. My symptoms are abdominal pain, protein in the urine, diarrhea, joint pain and swelling, nausea and vomiting.

I understand this is an illness mostly of children. How commonly do adults get it? I am in my mid-50s. The purple spots on my feet, legs and arms can be quite bad, and I have abdominal pain frequently. What happens when the abdominal pain occurs? Is it possible that this will go away on its own? – J.B.

ANSWER: The basic problem in Henoch-Schonlein purpura is inflammation of blood vessels. That makes it one of the vasculitis illnesses. The “purpura” of its name comes from bruises on the skin, a major clue to the diagnosis.

In addition to bruises, joints can swell and hurt, and stomach pain is common, as are nausea and vomiting. Bleeding from the digestive tract is another sign. Kidney involvement accounts for protein in the urine and for other signs of kidney troubles.

This is mostly a children’s illness – 90 percent of all cases are children. That means this rare childhood disease is very rare in adults.

Stomach pain comes about for the same reason that other signs and symptoms appear. The inflamed blood vessels don’t allow a sufficient supply of blood to get to the target organ. Stomach pain is often precipitated by eating when more blood is needed by the intestine to digest food.

Children usually recover from the illness in four to six weeks. With adults, it lingers longer, but most adults recover. Serious kidney involvement is not a good sign. You don’t have that. Urine protein, by itself, is not an indication of great kidney damage in this illness.

DEAR DR. DONOHUE: You wrote about endocarditis. I had endocarditis, and I have a bovine heart valve. You said the rules for taking antibiotics for dental work have been liberalized. Do I still need to take them? – C.S.

ANSWER: You have to continue to take antibiotics for dental procedures that cause bleeding. You are in a high-risk category for coming down with endocarditis again. You have an artificial heart valve, and you have had a previous bout of endocarditis.

Endocarditis is a bacterial infection of heart valves and the heart lining.

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