| Polycystic
Kidney Disease (PKD) is a disease affecting multiple
organs and consists of the formation of multiple
cysts fundamentally in the kidney. The cysts develop
from renal tubules and progressively enlarge by
accumulation of glomerular filtrate or secreted
solution. PKD is defined as five or more cysts
distributed through the renal cortex and medulla.
Two types have been described: autosomal dominant
and recessive. Autosomal dominant PKD presents
with incomplete penetrance, and has an incidence
of 1 in 400-1000 births. Three genes have been
implicated in its pathogenesis: PKD1 (chromosome
16), the most frequent, PKD2 (chromosome 4) and
PKD3 whose location has not been determined. Autosomal
recessive PKD is a rare illness (1:20 000 births).
The genetic defect is found in the short arm of
chromosome 6. It is a more florid illness with
lower survival and is associated with liver alterations
- cysts, fibrosis and portal hypertension.
The renal manifestations are: arterial hypertension
(proportionate to the size and number of cysts)
due to stimulation of the renin angiotensin system,
pain in the flanks, hematuria, non-nephrotic proteinuria
(<200mg/dl), urinary infections and kidney
stones. The most significant prognostic factor
for the development of kidney failure is arterial
hypertension. Terminal chronic kidney failure
is present in 50% of cases.
Extrarenal manifestations: liver cysts which
rarely affect liver function but can lead to superinfection;
cysts in the ovaries, pancreas and spleen but
without clinical effect. Also it may present with
cerebral aneurysm which, if ruptured, is the most
serious complication. There are frequently also
alterations in the gastrointestinal tract, eg
diverticula in the colon and hernias.
A precise diagnosis may be reached with image
tests such as abdominal ultrasound or CT along
with the presence of family genetic history of
the disorder. The diagnostic test with highest
certainty is a genetic study.
No definitive treatment exists and management
is based around prevention and treatment of complications.
This image shows bilateral massive polycystic
kidneys with intracystic haemorrhage.
Answer the autotest 
Authors:
Laura Salanova Villanueva, Marta Sánchez
Marteles
Servicios de Nefrología y Medicina Interna
Hospital Clínico Universitario “Lozano
Blesa”
Zaragoza
Translation: Kelly
Watt
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