Ethel Belford, age 13, of Jackson, Miss., for her question:

WHAT CAUSES UREMIA?

Uremia is a condition that occurs when poisonous wastes build up in the blood. Such wastes normally pass out of the body in the urine, which is produced by the kidneys. Uremia results if the kidneys do not rid the body of these wastes.

The word uremia means “urine in the blood.”

Uremia occurs mostly in adults who have a kidney disease. It develops gradually as more and more poisons accumulate because of the damaged kidneys.

Doctors can successfully treat some of the diseases that cause uremia. Drugs are usually used. But in most cases, the diseased kidneys cannot be repaired and advanced uremia occurs.

Doctors use two methods to keep advanced uremia victims alive. A dialysis machine cleans the blood in much the same way as the kidneys do. Surgeons also perform kidney transplants to replace diseased kidneys with healthy ones.