American Urological Association - Adult Polycystic Kidney Disease
Adult Polycystic Kidney Disease
- Patients present in 30-50's.
- Cysts only involve a portion of nephron, so renal function is maintained until 40's to 50's.
- Relatively common, seen in 1 of 400-1,000 live births and responsible for 5-10% of CRF requiring dialysis.
- Autosomal dominant; most common cystic renal disease and most common genetically transmitted disease (1:500 - 1:1000)
- 25% has no family history.
- Caused by mutations in genes at chr 16p13.3 (PKD1) that encodes for polycystin-1 and at chr 4q21 (PKD2) that encodes for polycystin-2.
- PKD1 is more common (85%) and associated with more severe disease and earlier onset (30's).
- Presents with hypertension, renal failure and abdominal pain.
- Extrarenal involvement: Liver cysts (90%), cyst in pancreas (10%), seminal vesicles, pineal glands, and mitral valve prolase.
- Gross: kidneys are massively enlarged and multicystic with essentially complete replacement of renal cortex (image A) & (image B). Hint: kidney larger and cyst more widespread than in acquired cystic disease (related to dialysis) because patients in the later have shrunken kidneys of CRF before acquiring cysts.
- Cystic dilatation of terminal ends of ampullary collecting ducts, proximal convoluted tubules, and Bowman's capsule (glomerular or tubular cysts) (image C).
- Cysts can be up to several centimeters.
- Cysts lined by a single layer of cuboidal or flattened cells.
- Complications: Metanephric abscesses; hypertension; berry aneurysms of Circle of Willis; nephrolithiasis; and RCC (1-5% of cases).
- CRF beginning at age 40-60 years.
- ~1/2 requires dialysis by age 50.