Polycystic Kidney Disease
In polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys. These expanding cysts destroy healthy kidney tissue. This destruction causes hypertension, pain, and other problems.
Polycystic kidney disease is the most common of all inherited renal diseases. There are more than 600,000 cases in the United States and about 12.5 million cases worldwide. Each year, 5 to 6 thousand new cases are diagnosed in the United States. In about 50% of cases, PKD progresses to end-stage renal disease by age 60. PKD accounts for approximated 3% of end-stage renal disease.
Two major inherited forms of polycystic kidney disease exist:
- Autosomal dominant polycystic kidney disease is the most common inherited form. 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.
- Autosomal recessive polycystic kidney disease is a rare inherited form. Symptoms of autosomal recessive PKD begin in the earliest months of life, even in the womb.
In polycystic kidney disease, the cysts actually form in the kidney and other organs. These cyst cause discomfort and pain by putting pressure on the surrounding tissues, by bleeding into the cysts, and by the development of kidney stones or infected cysts. Kidney stones occur in about 20% of patients with PKD.
Cysts in the liver develop in about 80% of patients. Fortunately, the cysts do not affect liver function. They are estrogen-dependent and can be more of a problem in women.
About 10% of patients have cysts in the pancreas. Fortunately, these cysts do not significantly affect the function of the pancreas.
Patients with polycystic kidney disease disease are at increased risk of intracranial aneurysms. A patient with PKD who has a family member with PKD as well as an intracranial aneurysm or subarachnoid hemorrhage has about a 20% chance of having an intracranial aneurysm of their own. A PKD patient who has a “thunderclap” headache should be seen immediately by a physician. This type of headache in a PKD patient can signal a leaking aneurysm that may be ready to actually rupture. This is a critical period when a patient should immediately obtain emergency care.
Polycystic kidney disease patients have an increased risk of cardiac valve abnormalities (most commonly the mitral valve) and hernias (umbilical, hiatal, and inguinal hernias).
Good advise for patients with polycystic kidney disease
Drink approximately 3 L of water throughout the day right up to bedtime. This should be done under a doctor’s direction and with regular monitoring.
Avoid caffeine and methylxanthines .
Follow a low-sodium diet (< 2,300 mg/day), which, while helping to control hypertension and kidney stone formation, may also help to maintain smaller cysts and kidneys.
Work with your doctor to control your hypertension. The target blood pressure should be in the range of 110 to 130 mm Hg systolic and 70 to 80 mm Hg diastolic.
Autosomal dominant polycystic kidney disease: Emerging concepts of pathogenesis and new treatments; Cleveland Clinic Journal of Medicine February 2009 vol. 76 no. 2 97-104; William E. Braun, MD
National Kidney and Urologic Diseases