Polycystic Kidney Disease

Definition

Polycystic kidney disease (PKD) is an inherited disease that causes many cysts to form in the kidneys.

Cysts, which are sacs filled with fluid, grow in both kidneys causing them to become enlarged. The number of cysts can range from a few to a great number. The size of the cysts can vary from too small to detect, to cysts that are larger than the kidney itself.

Anatomy of the Kidney

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Causes

PKD is caused by an inherited gene. Children have a 50% chance of developing PKD if 1 parent carries the gene. If a person has the PKD gene, he or she will have some form of the disease in his or her lifetime.

There is also a rare form of PKD, called autosomal recessive polycystic kidney disease, that affects newborns, infants, and children. This form of PKD can cause death in the first month of life.

Risk Factors

The primary risk factor for PKD is having a parent with the disease. In about 10% of cases, the gene for the disease was not inherited, but mutated. PKD affects men and women equally.

Symptoms

During the early stages of PKD, there are often no symptoms. Some people are never diagnosed because their symptoms are mild. Most symptoms appear in middle age.

Frequently, the first symptom is pain in the back or side. Other signs of PKD include:

• Blood in the urine
• Abdominal pain
• Frequent urination

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. When diagnosing PKD, your doctor may begin by looking for signs of the disease.

Your bodily fluids may be tested. This can be done with:

• Blood tests
• Urine tests

Imaging tests may be done to evaluate the kidneys. This can be done with:

• Ultrasound
• CT scan
• MRI scan

Ten to forty percent of patients with PKD also have an aneurysm in the brain. An aneurysm is a weakness in the wall of a blood vessel. If you are diagnosed with PKD and have a family history of a brain aneurysm, your doctor may advise an arteriogram to detect the presence of an aneurysm.

Treatment

Most treatments for PKD treat the disease symptoms or prevent complications. Some of these treatment options may include:

• High blood pressure medication—Since high blood pressure is common with PKD, medications are often prescribed to control blood pressure.
• Pain medication—Pain medications must be used cautiously, since some of them can cause damage to the kidneys.
• Antibiotics—In the event of a urinary tract infection, treatment with a certain type of antibiotics is needed to avoid damage to the kidneys d reach infections that occur within the cysts.
• Surgery—Cysts may be drained through surgery to relieve pain, blockage, infection, or bleeding. Cyst drainage may also temporarily lower blood pressure. Sometimes, one or both kidneys may be removed if pain is severe. This procedure is called nephrectomy.
• Diet—A low-protein diet may reduce stress on the kidney. Avoiding salt can help keep normal blood pressure. Drinking plenty of water can also help reduce the risk of kidney stones.
• Dialysis and transplantation—More than half of PKD patients develop kidney failure and need dialysis. Dialysis is used to remove wastes from the blood, since the kidneys cannot. At this stage, dialysis will be a lifelong requirement unless a kidney transplant from a donor can be done successfully.

Prevention

PKD is an inherited disease and is not preventable. If you have a family history of PKD, you may want to talk to your doctor about genetic testing.