Hydronephrosis is a medical condition which is commonly caused by an obstruction of the urine flow from the kidney. The condition involves a dilation and distention of the renal pelvis. Hydronephrosis may be either acute or chronic in nature.
The obstruction in hydronephrosis can possibly be either complete or partial, and occur anywhere between the areas of the urinary meatus and the renal pelvis calyces. Additionally, the obstruction may be based from outside or inside of the urinary tract.
Some obstructions which may be causes of hydronephrosis include:
Within the urinary tract
Outside of the urinary tract