POLYCYSTIC KIDNEY

Polycystic kidney disease (PKD) is a disorder in which clusters of cysts develop primarily within your kidneys. Cysts are noncancerous round sacs containing water-like fluid.

Polycystic kidney disease isn't limited to only kidneys, although the kidneys usually are the most severely affected organs. The disease can cause cysts to develop elsewhere in body.

The greatest risk for people with polycystic kidney disease is developing high blood pressure. Kidney failure is another common problem for people with polycystic kidney disease.

Polycystic kidney disease varies greatly in its severity, and some complications are preventable. Regular checkups can lead to treatments to reduce damage to kidneys from complications, such as high blood pressure.

Cysts are noncancerous (benign), round sacs that contain water-like fluid. They vary in size and as they accumulate more fluid can grow extremely large. A kidney containing numerous cysts can weigh as much as 30 pounds.

Abnormal genes cause polycystic kidney disease, and the genetic defects mean the disease runs in families. There are two types of polycystic kidney disease, caused by different genetic flaws:

• Autosomal dominant polycystic kidney disease (ADPKD). Signs and symptoms of ADPKD often develop between the ages of 30 and 40. In the past, this type was called adult polycystic kidney disease, but children can develop the disorder. Only one parent needs to have the disease in order for it to pass along to the children. If one parent has ADPKD, each child has a 50 percent chance of getting the disease. This form accounts for about 90 percent of cases of polycystic kidney disease.
• Autosomal recessive polycystic kidney disease (ARPKD). This type is far less common than ADPKD. The signs and symptoms often appear shortly after birth. Sometimes, symptoms don't appear until later in childhood or during adolescence. Both parents must have abnormal genes to pass on this form of the disease. If both parents carry the genes for this disorder, each child has a 25 percent chance of getting the disease.

Researchers have identified two genes associated with ADPKD and one associated with ARPKD so far.

In some cases, a person with ADPKD has no known family history of the disease. But it's possible that someone in the affected person's family actually did have the disease, but didn't show signs or symptoms before dying of other causes. In a smaller percentage of cases where no family history is present, ADPKD results from a spontaneous gene mutation.

SYMPTOMPS

Polycystic kidney disease symptoms may include:

• High blood pressure
• Back or side pain related to enlarged kidneys
• Headache
• Increase in the size of your abdomen
• Blood in your urine
• Frequent urination
• Kidney stones
• Kidney failure
• Urinary tract or kidney infections

COMPLICATIONS

• High blood pressure. Elevated blood pressure is a common complication of polycystic kidney disease. Untreated, high blood pressure can cause further damage to your kidneys and increase your risk of heart disease and stroke.

• Loss of kidney function. Progressive loss of kidney function is one of the most serious complications of polycystic kidney disease. Nearly half of those with the disease have kidney failure by age 60, and up to 75 percent have kidney failure by age 70. If you have high blood pressure or blood or protein in your urine, you have a greater risk of kidney failure.

  Polycystic kidney disease causes your kidneys to gradually lose their ability to eliminate wastes from your blood and maintain your body's balance of fluids and chemicals. As the cysts enlarge, they produce pressure and promote scarring in the normal, unaffected areas of your kidneys. These effects result in high blood pressure and interfere with the ability of your kidneys to keep wastes from building to toxic levels, a condition called uremia. As the disease worsens, end-stage kidney (renal) failure may result. When end-stage renal failure occurs, you'll need ongoing kidney dialysis or a transplant to prolong your life.

• Pregnancy complications. Pregnancy is successful for most women with polycystic kidney disease. In some cases, however, women may develop a life-threatening disorder called preeclampsia. Those most at risk are women who have high blood pressure before they become pregnant.
• Growth of cysts in your liver. The likelihood of developing liver cysts for someone with polycystic kidney disease increases with age. While both men and women develop cysts, women often develop larger cysts. Cyst growth may be aided by female hormones.
• Development of an aneurysm in your brain. Localized enlargement of an artery in your brain can cause a hemorrhage if it ruptures. People with polycystic kidney disease have a higher risk of aneurysm, especially those that occur before age 50. The risk is higher if you have a family history of aneurysm or if you have uncontrolled high blood pressure.
• Heart valve abnormalities. As many as one-quarter of adults with polycystic kidney disease develop mitral valve prolapse. When this happens, the valve no longer closes properly, which allows blood to leak backward.
• Colon problems. Hernias and pouches or sacs in the wall of the colon (diverticulosis) may develop in people with polycystic kidney disease.
• Chronic pain. Pain is a common symptom for people with polycystic kidney disease. It often occurs in your side or back. The pain also can be associated with a urinary tract infection or a kidney stone.

-MayoClinic-