What is hidronefrosis?

Hydronephrosis. It is the enlargment and dilatation of the kidney usually secondary to an obstruction. If it is not treated, it can lead to permanent kidney damage.
Hydronephrosis. Refers to swelling on the kidney. Causes are: normal anatomic variant, ureteropelvic junction obstruction, vesicourteroreflux, blockage of the ureters from surgery or radiation, and others. Untreated blockage to the kidney is not immediately dangerous, but may eventully cause kidney injury.