What is polycystic kidney disease?
Polycystic kidney disease (also called PKD) causes numerous cysts to grow in the kidneys. These cysts are filled with fluid. If too many cysts grow or if they get too big, the kidneys can become damaged. PKD cysts can slowly replace much of the kidneys, reducing kidney function and leading to kidney failure.
How common is PKD?
In the United States about 600,000 people have PKD. It is the fourth leading cause of kidney failure. It is found in all races and occurs equally in men and women. It causes about 5% of all kidney failure.
What other organs besides the kidney are affected by PKD?
PKD can affect other organs besides the kidney. People with PKD may have cysts in their liver, pancreas, spleen, ovaries, and large bowel. Cysts in these organs usually do not cause serious problems, but can in some people. PKD can also affect the brain or heart. If PKD affects the brain, it can cause an aneurysm. An aneurysm is a bulging blood vessel that can burst, resulting in a stroke or even death. If PKD affects the heart, the valves can become floppy, resulting in a heart murmur in some patients.
What are the clues that someone has PKD?
Most people do not develop symptoms until they are 30 to 40 years old. The first noticeable signs and symptoms may include:
Back or side pain
An increase in the size of the abdomen
Blood in the urine
Frequent bladder or kidney infections
High blood pressure
High blood pressure is the most common sign of PKD. Occasionally, patients may develop headaches related to high blood pressure or their doctors may detect high blood pressure during a routine physical exam. Because high blood pressure can cause kidney damage, it is very important to treat it. In fact, treatment of high blood pressure can help slow or even prevent kidney failure.
Fluttering or pounding in the chest
About 25% of PKD patients have a so-called floppy valve in the heart, and may experience a fluttering or pounding in the chest as well as chest pain. These symptoms almost always disappear on their own but may be the first hint that someone has PKD.
How is PKD diagnosed?
Ultrasound is the most reliable, inexpensive and non-invasive way to diagnose PKD. If someone at risk for PKD is older than 40 years and has a normal ultrasound of the kidneys, he or she probably does not have PKD. Occasionally, a CT scan (computed tomography scan) and MRI (magnetic resonance imaging) may detect smaller cysts that cannot be found by an ultrasound. MRI is used to measure and monitor volume and growth of kidneys and cysts.
In some situations, genetic testing might also be done. This involves a blood test that checks for abnormal genes that cause the disease. Genetic testing is not recommended for everyone. The test is costly, and it also fails to detect PKD in about 15% of people who have it. However, genetic testing can be useful when a person:
has an uncertain diagnosis based on imaging tests
has a family history of PKD and wants to donate a kidney
is younger than 30-years old with a family history of PKD and a negative ultrasound, and is planning to start a family