What is hydronephrosis?
Hydronephrosis is swelling (dilation) of the urine-collecting structures of one or both kidneys due to obstruction of urine flow from the kidney. This can impair kidney function. Hydronephrosis isn't a specific disease, but a sign of an underlying problem. Causes include:
Hydronephrosis may develop suddenly — due to, for example, passing a kidney stone — and cause severe pain in the back, lower abdomen and groin on the side of the blockage. It may also develop so gradually over weeks or months — due to, for example, a slow-growing tumor — that it causes no symptoms. Urine output usually remains normal as long as one kidney functions properly.
A doctor can confirm a diagnosis of hydronephrosis by:
Treatment depends on the cause and the severity of the obstruction. Some blockages, such as from blood clots or a kidney stone, can resolve without treatment. Surgery may be necessary to relieve the blockage. Rarely, surgical removal of the kidney may be required.
Last Updated: 05/10/2006
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