Polycystic Kidney Disease Complications

Polycystic kidney disease is a genetic condition in which many cysts form in the kidneys. The fluid-filled cysts continue to grow and even though the kidney expands to accommodate them, eventually they take over the healthy kidney tissue. When this happens the kidney can't continue to function and complications rapidly follow.

Definition

• Structures in the kidneys called nephrons are responsible for filtering wastes and fluid from the blood. The cysts grow out of the nephrons, but over time they separate and continue to get larger. There can be thousands of cysts, causing the kidney to weigh as much as 20 to 30 pounds. As they grow they displace healthy kidney tissue.

Types

• The two major types of polycystic kidney disease (PKD), autosomal dominant and autosomal recessive, carry different complications represented by the chance of developing the disease.

  Autosomal dominant means that if one parent has the disease, there is a 50 percent chance that his children will get the disease. The dominant type accounts for about 90 percent of all cases of PKD and is sometimes called "adult polycystic kidney."

  The recessive type is rare and begins in the early months of an infant's life. If only one parent carries the gene, the baby will not develop the disease but can pass it on to his children. If both parents have the gene, then the child has a 25 percent chance of developing PKD.

Complications

• The ultimate complication is that PKD is the fourth leading cause of kidney failure. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), about half of those with dominant PKD will ultimately progress to kidney failure and about 10 percent to end-stage renal disease. Cysts can also develop in the liver and pancreas. High blood pressure is very common in people with PKD and usually develops by the age of 30. Pain related to the growing cysts is a common complication. Headaches may result from the high blood pressure or they may indicate aneurysms, which are a risk for those with PKD.

  The recessive type affects the liver and spleen, causing low blood cell counts, varicose veins and hemorrhoids. Another complication facing children with recessive PKD is that decreased kidney functioning directly impacts growth, causing these children to be smaller than their typical peers.

Symptoms

• The symptoms of each type are a little different. In dominant PKD, pain in the back and sides and headaches are the most common symptoms. Other symptoms include blood in the urine, high blood pressure, and urinary tract infection. A complication for the recessive type is that the symptoms vary. They can be so severe that they progress to kidney failure in the first few years of life, or there may not be any symptoms until later in life. Other symptoms of recessive PKD include high blood pressure, frequent urination and urinary tract infections.

Treatment

• There is no cure for PKD, so treatment focuses on managing the symptoms. Controlling the high blood pressure can slow the progression of dominant PKD and that can help prevent complications. Surgery can be performed to shrink the cysts, but they can not be surgically removed so the progression toward kidney failure is not stopped. In children, treatment may include a special diet and hormones to help with growth issues. In both types, the only options for kidney failure or end-stage renal disease are dialysis or kidney transplantation.