Causes

Kidney, Ureter, Bladder, and Kidney Stone

© 2009 Nucleus Medical Art, Inc.

Hydronephrosis is caused by two problems in the urinary system. A blockage may prevent urine from draining out of the kidneys. Or a condition called reflux may cause urine to flow back into the kidneys from the bladder.

Conditions that may cause hydronephrosis include:

• A blockage or defect in the urinary system that is present at birth
• Kidney stones
• A blood clot
• Scarring of the ureters (tubes that connect the kidneys to the bladder)
• A tumor in the pelvic area (such as bladder, cervix, colon, or prostate)
• Enlarged prostate
• Enlarged uterus during pregnancy
• Persistent urinary infection in the kidneys
• Neurogenic bladder
• Injury to structures in the urinary system (eg, from surgery or trauma)

Risk Factors

The following factors increase your chances of developing hydronephrosis:

• Defect in the urinary system that is present at birth
• Cancers in the pelvic area
• Pelvic surgery
• Blood-clotting disorders
• Recurrent urinary tract infections
• Enlarged prostate
• Neurogenic bladder
• Pregnancy