Table of Contents
Definition of Polycystic Kidney
The cysts greatly enlarge and deform the kidneys.
The cysts arise from the nephrons, which they destroy as they grow.
Polycystic kidney disease affects about 500,000 people in the United States and is the fourth-leading cause of END-STAGE RENAL DISEASE (ESRD). About 10 percent of people on long-term RENAL DIALYSIS have polycystic kidney disease.
The most common type of polycystic kidney disease is autosomal dominant, which affects more than 90 percent of people who have the condition. It occurs as the result of mutations in the pkd1 GENE located on chromosome 16 and the PKD2 gene on chromosome 4. GENETIC TESTING can detect the presence of these mutations, which confirms the diagnosis.
The progression of kidney damage in autosomal dominant polycystic kidney disease typically takes place over decades, with symptoms beginning to manifest around age 30 to 40. A much less common type of polycystic kidney disease is autosomal recessive, which has a different clinical presentation and course of disease. Its symptoms are often present at birth or appear in early childhood.
Symptoms and Diagnostic Path
Autosomal dominant polycystic kidney disease typically shows no symptoms until the person is age 30 to 40. At that time the cysts become numerous enough and large enough to cause pain and disrupt kidney function. Urinary system symptoms that emerge include
- HEMATURIA (bloody URINE)
- frequent, recurrent URINARY TRACT INFECTION (UTI)
- kidney stones (NEPHROLITHIASIS)
- upper ABDOMINAL PAIN
Additional symptoms include HYPERTENSION (high BLOOD PRESSURE) resulting from damage to the kidneys and cysts in the liver and other organs. Diverticulosis, a gastrointestinal condition in which small pockets distend from the bowel, is also common. Some people may have deformed heart valves and deformities in blood vessels that cause aneurysms to develop.
Treatment Options and Outlook
Treatment focuses on relieving symptoms. ANTIBIOTIC MEDICATIONS are necessary to treat a UTI. Surgery may be necessary to repair any ANEURYSM and sometimes to reduce the size of the kidneys. Most people progress to ESRD within 10 years of the appearance of symptoms, at which time renal dialysis becomes necessary to sustain life. KIDNEY TRANSPLANTATION is often a viable treatment option. The transplanted kidney does not develop cysts. However, cysts do continue to develop in other organs.
Risk Factors and Preventive Measures
Polycystic kidney disease is both genetic and inherited. People who have this condition in their families may benefit from genetic testing to determine whether they carry the mutated genes, and to discuss their family planning options with a genetic counselor.