Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys. When cysts form in the kidneys, they are filled with fluid. PKD cysts can profoundly enlarge the kidneys while replacing much of the normal structure, resulting in reduced kidney function and leading to kidney failure.
When PKD causes kidneys to fail, which usually happens after many years, the patient requires dialysis or kidney transplantation. About one-half of people with the most common type of PKD progress to kidney failure, also called end-stage renal disease (ESRD).
PKD can also cause cysts in the liver and problems in other organs, such as blood vessels in the brain and heart. The number of cysts, as well as the complications they cause, help doctors distinguish PKD from the usually harmless “simple” cysts that often form in the kidneys in later years of life.
The symptoms and signs of PKD include:
- Pain in the back and lower sides
- Urinary tract infections
- Blood in the urine
- Cysts in the kidneys and other organs
There are two types of PKD, depending on the genetic basis of the disease. They are autosomal dominant PKD (the most common) and autosomal recessive PKD. Autosomal dominant symptoms usually develop between the ages of 30 and 40, but they can begin earlier, even in childhood. About 90 percent of all PKD cases are autosomal dominant PKD.
The autosomal recessive PKD is a rare inherited form. Symptoms of autosomal recessive PKD begin in the earliest months of life, even in the womb.
Signs and tests
Polycystic kidney disease is diagnosed using ultrasound imaging of the kidney cysts, and ultrasound imaging of cysts in other organs. The physicians will take a detailed family medical history, including genetic testing when possible.
PKD is not curable. Treatment includes medications to reduce the symptoms’ effects and prolong your life.
Pain: Pain in the area of the kidneys can be caused by cyst infection, bleeding into cysts, kidney stones, or stretching of the fibrous tissue around the kidney with cyst growth. A doctor will first evaluate which of these causes are contributing to the pain to guide treatment. If it is determined to be chronic pain due to cyst expansion, the doctor may initially suggest over-the-counter pain medications, such as aspirin or acetaminophen (Tylenol). Consult your doctor before taking any over-the-counter medication because some may be harmful to the kidneys. For most but not all cases of severe pain due to cyst expansion, surgery to shrink cysts can relieve pain in the back and sides. However, surgery provides only temporary relief and does not slow the disease’s progression toward kidney failure.
Headaches: Headaches that are severe or that seem to feel different from other headaches might be caused by aneurysms-blood vessels that balloon out in spots-in the brain. These aneurysms could rupture, which can have severe consequences. Headaches also can be caused by high blood pressure. People with autosomal dominant PKD should see a doctor if they have severe or recurring headaches, even before considering over-the-counter pain medications.
Urinary tract infections. People with autosomal dominant PKD tend to have frequent urinary tract infections, which can be treated with antibiotics. People with the disease should seek treatment for urinary tract infections immediately because infection can spread from the urinary tract to the cysts in the kidneys. Cyst infections are difficult to treat because many antibiotics do not penetrate the cysts.
High blood pressure. Keeping blood pressure under control can slow the effects of autosomal dominant PKD. Lifestyle changes and various medications can lower high blood pressure. Patients should ask their doctors about such treatments. Sometimes proper diet and exercise are enough to keep blood pressure controlled.
End-stage renal disease: After many years, PKD can cause the kidneys to fail. Because kidneys are essential for life, people with ESRD must seek one of two options for replacing kidney functions: dialysis or transplantation. In hemodialysis, blood is circulated into an external filter, where it is cleaned before re-entering the body; in peritoneal dialysis, a fluid is introduced into the abdomen, where it absorbs wastes and is then removed. Transplantation of healthy kidneys into ESRD patients has become a common and successful procedure. Healthy-non-PKD-kidneys transplanted into PKD patients do not develop cysts.