What is hydronephrosis?

Also known as: hydronephrosis of one kidney.

The urinary tract has 4 parts: two kidneys, the two ureters through which urine flows to the bladder, the bladder and the urethra the short tube out of the bladder through which urine is passed out of the body.

Hydronephrosis is a condition where one or both kidneys swell either because of a blockage/obstruction of urine flow or because of reverse urine flow from the bladder (reflux).

Hydronephrosis may be mild, moderate or severe.

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Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: 1/29/2019 3:21:13 PM