Encyclopedia of Health and Medicine

P
percutaneous lithotripsy See EXTRACORPOREAL
SHOCK WAVE LITHOTRIPSY (ESWL).
polycystic kidney disease An inherited disorder
in which hundreds to thousands of cysts form in
the KIDNEYS as well as in other organs and structures
such as the LIVER, HEART, and BRAIN. 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
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• 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. ANTIBI-
OTIC 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.
See also INHERITANCE PATTERNS; RENAL CYST.
proteinuria
pyelonephritis
See ALBUMINURIA.
See NEPHRITIS.