Polycystic kidney disease

Alternative names:

autosomal dominant polycystic kidney disease; cysts - kidneys; kidney - polycystic; PCKD

Definition:

An inherited kidney disorder which enlarges the kidneys and interferes with their function because of multiple cysts on the kidneys.

Causes, incidence, and risk factors:

Polycystic kidney disease (PCKD) is an inherited disorder (with autosomal dominant inheritance--if one parent transmits the gene, 50% of the children will develop the disorder) where multiple clusters of cysts form on the kidneys. The exact mechanism that triggers cyst formation is unknown.

Cysts in the kidneys are often associated with aneurysms of the blood vessels in the brain. They may be associated with diverticula of the colon, and with cysts in the liver, pancreas, and testes. As many as 50% of people with polycystic kidney disease also have cysts on the liver.

In early stages of the disease, the cysts enlarge the kidney and interfere with kidney function, resulting in chronic high blood pressure, anemia, and kidney infections. The cysts may cause the kidneys to increase production of erythropoietin (the hormone that stimulates production of red blood cells) resulting in increased number of red blood cells, rather than the expected anemia. Bleeding into a cyst can cause flank pain. Kidney stones are more common than in people without the disorder. Hypertension caused by polycystic kidneys may be difficult to control.

The disease is slowly progressive, eventually resulting in end-stage kidney failure. It is also associated with liver disease, including infection of liver cysts. If polycystic kidney disease appears in childhood, it tends to be very serious and progresses more rapidly, resulting in end-stage kidney failure and causing death in infancy or childhood.

PCKD occurs in both children and adults, but it is much more common in adults, often not presenting symptoms until middle age. Approximately 2 out of 10,000 people have polycystic kidney disease. The actual number may be more, as some people do not have symptoms. The disorder may not be discovered unless procedures showing the disease are performed for other reasons.

Risks include a personal or family history of polycystic kidney disease.