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 KIDNEYSas well as in other organs and struc-
tures such as the LIVER, HEART, andBRAIN. 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 DIALYSIShave 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 condi-
tion. It occurs as the result of mutations in the
PKD1 GENElocated on CHROMOSOME16 and the
PKD2 gene on chromosome 4. GENETIC TESTINGcan
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 differ-
    ent 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)


• upperABDOMINAL 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

TRANSPLANTATIONis 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 deter-

mine whether they carry the mutated genes, and

to discuss their family planning options with a

genetic counselor.

See also INHERITANCE PATTERNS; RENAL CYST.

proteinuria See ALBUMINURIA.

pyelonephritis See NEPHRITIS.

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