Polycystic Kidney Disease

This hereditary kidney disorder occurs in two main forms. The more common form, known as adult polycystic disease (APCD), usually develops in adulthood but may, in rare cases, manifest itself in infancy or childhood. Much less common is infantile polycystic disease (IPCD), which is usually apparent soon after birth and is accompanied by liver abnormalities.

In both forms of the disease, the kidney is riddled with fluid-filled growths called cysts. These cysts, which usually appear in both kidneys, severely impair kidney functioning. In the infantile form of the disease, the kidneys may be either enlarged or underdeveloped.

Some infants also are born with a noninherited cystic kidney disorder called multicystic kidney of the newborn. This disorder, which usually affects only one kidney, occurs when the ureter (the tube to the bladder) develops abnormally, causing the kidney to degenerate into an irregular mass of cysts.

HOW DOES POLYCYSTIC KIDNEY DISEASE DEVELOP?
APCD is inherited as a dominant trait, which means that 50 percent of the children of an affected parent will develop the disease. IPCD is inherited as a recessive trait, which means that both parents carry the disease gene—and the child must inherit both copies—to develop the disease. In this circumstance, 25 percent of children will develop this rare disease.

WHEN SHOULD I SUSPECT THAT MY CHILD HAS POLYCYSTIC KIDNEY DISEASE?
Multicystic kidney of the newborn is usually discovered soon after birth, since the abnormal kidney can often be felt as a large mass in the abdomen. If the other types of polycystic disease do not become apparent during infancy, they may cause a number of symptoms later on, including enlargement of the liver and spleen, pain in the side and lower back and frequent urinary tract infections. The kidneys may, in addition, become so large that they can be felt as hard masses on the sides of the trunk.

HOW CAN THE PEDIATRICIAN TELL IF MY CHILD HAS POLYCYSTIC KIDNEY DISEASE?
The main diagnostic tools are ultrasound, computed tomography (CT) scanning and conventional X rays.

WHAT TREATMENTS ARE AVAILABLE?
Treatment options are limited. Because cysts recur, surgery to remove them is ineffective. Ultimately, polycystic kidney disease progresses to kidney failure, necessitating dialysis (filtering of the blood with an artificial kidney) or transplantation.

GETTING HELP
Since polycystic kidney disease is usually hereditary, couples with family histories of the disease should seek genetic counseling to determine whether they risk passing it to their children. For more information, see genetic disorders.

Excerpt from THE DISNEY ENCYCLOPEDIA OF BABY & CHILD CARE, © 1995 DSH Communications, Inc. This material is based on current medical research and, to the best of the editors' knowledge and understanding, is accurate and valid. However the reader should not use information contained in this material to alter a medically prescribed regimen or as a form of self-treatment, without seeking the advice of a licensed physician.