[Renal failure and cystic kidney diseases]

Cystic kidney diseases often are discovered at the time of initial work-up of renal failure through ultrasound or family history, or incidentally at the time of an imaging test. Hereditary diseases include autosomal dominant or recessive polycystic kidney disease (PKD), tuberous sclerosis (TS) and medullary cystic kidney disease (MCKD). Autosomal dominant PKD is characterized by large renal cysts developing in young adults. Renal failure is progressive and becomes severe around 50-60 years of age. Atypical cysts (hemorrhagic or hyperdense) are frequent on CT and MRI examinations. Imaging plays a valuable role in the management of acute complications such as cyst hemorrhage or infection. Autosomal recessive PKD is often detected in neonates, infants or young adults. It is characterized by renal enlargement due to the presence of small cysts and liver disease (fibrosis and biliary ductal dilatation). Late manifestation or slow progression of autosomal recessive PKD may be more difficult to distinguish from autosomal dominant PKD. These cystic kidney diseases should not be confused with non-hereditary incidental multiple renal cysts. In tuberous sclerosis, renal cysts are associated with angiomyolipomas and sometimes pulmonary lymphangioleiomyomatosis. Renal failure is inconstant. Other hereditary cystic kidney diseases, including MCKD and nephronophtisis, are usually associated with renal failure. Non-hereditary cystic kidney diseases include multicystic renal dysplasia (due to complete pelvi-ureteric atresia or hydronephrosis), acquired multicystic kidney disease (chronic renal failure, chronic hemodialysis) and varied cystic kidney diseases (multicystic renal disease, glomerulocystic kidney disease, microcystic kidney disease).