All Children's Hospital Logo

Health Information Library

Parents > A to Z > H > A to Z: Hydronephrosis
A to Z: Hydronephrosis

A to Z: Hydronephrosis

May also be called: Unilateral Hydronephrosis; Bilateral Hydronephrosis; Urinary Obstruction; Swollen Kidneys

Hydronephrosis (hi-dro-ne-FRO-sis) is when one or both kidneys become enlarged because the flow of urine (pee) is backed up or blocked.

More to Know

Normally, urine flows from the kidneys to the bladder through thin tubes called ureters. But some conditions and obstructions in the urinary tract can block the normal flow of urine or reverse the urine flow. This can cause a buildup of urine in the kidney, leading to hydronephrosis, or swelling of the kidneys. Hydronephrosis can sometimes be diagnosed before a baby is born on prenatal ultrasound.

Hydronephrosis may lead to a urinary tract infection or cause pain in the abdomen. The two main causes of hydronephrosis include blockage of urine flow (which can occur at different points in the urinary tract) and urine reflux (a reversal of urine flow).

Keep in Mind

Many times, hydronephrosis resolves on its own without treatment. However, if treatment is needed, most causes of hydronephrosis can be resolved with medications or minor surgery.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.

Related Articles
P    Kidneys and Urinary Tract
T    Kidneys and Urinary Tract
K    Movie: Urinary System
P    Ultrasound: Bladder
P    Ultrasound: Renal (Kidneys, Ureters, Bladder)
P    Urinary Tract Infections
T    Urinary Tract Infections
K    Urinary Tract Infections (UTIs)
K    Your Kidneys
K    Your Urinary System
Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
© 1995-2014 KidsHealth® All rights reserved. Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

Additional Info

Pocket Doc Mobile App
Maps and Locations (Mobile)
Programs & Services
Employment
For Health Professionals
For Patients & Families
Contact Us
Find a Doctor
News
CME

All Children's Hospital
501 6th Ave South
St. Petersburg, FL 33701
(727) 898-7451
(800) 456-4543

Use Normal Template
© 2014 All Children's Hospital - All Rights Reserved