• Hydronephrosis—Child


    Hydronephrosis is when one or both kidneys swell with backed up urine. This swelling can lead to kidney infection or kidney damage.
    Hydronephrosis is not a condition but a symptom of another condition.
    Urinary Tract System
    Copyright © Nucleus Medical Media, Inc.


    Hydronephrosis is caused by urinary tract problems that makes it difficult for urine to leave the kidneys. Urine may be slowed or blocked by:
    • An obstruction, bulge, or narrowing in the tube that carries urine from the kidney to the bladder
    • In boys, flaps of tissue obstructing the tube that carries urine out of the body or narrowing of the tip of the penis
    Other conditions that may cause problems with urine flow include:
    • The backwards flow of urine from the bladder into the kidneys
    • Problems with the tube that carries urine to the bladder or in the way that it connects
    • Occasionally, an abnormal kidney
    In most cases, the child is born with one of these conditions that affect the urinary tract. For some, the condition develops later on. Sometimes the cause of hydronephrosis is not known.

    Risk Factors

    Hydronephrosis is more common in boys than girls.


    Hydronephrosis may cause:
    • Pain in the back, sides, abdomen, or groin
    • Blood in the urine
    • Trouble feeding
    • Poor growth
    • Symptoms of urinary tract infection


    Most often hydronephrosis is diagnosed during pregnancy during a maternal ultrasound.
    After birth you will be asked about your child’s symptoms and medical history. A physical exam will be done. Your doctor may be able to feel the swollen kidney during the physical exam.
    Your child's bodily fluids may be tested. This can be done with:
    • Urine tests
    • Blood tests
    Imaging tests evaluate bodily structures. These may include:
    • Ultrasound—may be done before and/or after birth
    • Voiding cystourethrogram—x-rays of the bladder and urethra taken during urination
      • Note: This test is only done if there is hydronephrosis still present after birth.
    • MRI scan
    • CT scan
    • Cystoscopy


    Hydronephrosis that develops before birth will often resolve on its own without kidney damage, either before or after birth. Your child's kidneys will be monitored until the swelling has gone away.
    When necessary, the condition causing the back up of urine will be treated. Treatment options may include:


    Medications may include:
    • Over-the-counter medication to reduce pain and/or fever
    • Antibiotics to prevent or treat infection


    If the hydronephrosis is causing painful symptoms, there are signs of kidney damage, and there is a correctable lesion that will not get better on its own surgery may need to be done to allow urine to flow properly. The type of surgery that is done depends on the cause of your child's hydronephrosis. In rare cases, surgery may need to be done before birth.


    There are no current guidelines to prevent hydronephrosis.


    American Kidney Fund http://www.akfinc.org

    National Kidney Foundation http://www.kidney.org


    BC Children’s Hospital http://www.bcchildrens.ca

    The Kidney Foundation of Canada http://www.kidney.ca


    Herz D, Merguerian P, et al. Continuous antibiotic prophylaxis reduces the risk of febrile UTI in children with asymptomatic antenatal hydronephrosis with either ureteral dilation, high-grade vesicoureteral reflux, or ureterovesical junction obstruction. J Pediatr Urol. 2014;10(4):650-654.

    Hydronephrosis. Boston Children’s Hospital website. Available at: http://www.childrenshospital.org/health-topics/conditions/hydronephrosis. Accessed March 10, 2016.

    Hydronephrosis. University of California Davis Health System website. Available at: http://www.ucdmc.ucdavis.edu/urology/downloads/kurzrock%5Fhandouts%5FPDF/Hydronephrosis.pdf. Accessed March 10, 2016.

    Hydronephrosis. University of California San Francisco Benioff Children's Hospital website. Available at: http://www.ucsfbenioffchildrens.org/conditions/hydronephrosis/index.html. Accessed March 10, 2016.

    Vesicoureteral reflux. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116455/Vesicoureteral-reflux. Updated May 23, 2016. Accessed March 10, 2016.

    4/1/2014 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Choosing wisely. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T116455/Vesicoureteral-reflux. Updated March 26, 2014. Accessed August 13, 2014.

    Revision Information

    • Reviewer: EBSCO Medical Review BoardKari Kassir, MD
    • Review Date: 03/2017
    • Update Date: 08/13/2014
  • LiveWell personal health survey

    How healthy are you really? Find out – free.Learn more

    It's time to stop guessing. If you want to make some changes but just aren't sure how, the free personal health survey from LiveWell is a great place to start.

  • HeartSHAPE Spotlight

    At risk for a heart attack? Learn more

    Fight heart disease and prevent heart attacks. HeartSHAPE® is a painless, non-invasive test that checks pictures of your heart for early-stage coronary disease.

  • Calories and Energy Needs

    Calorie NeedsLearn more

    How many calories do you need to eat each day to maintain your weight and fuel your physical activity? Enter a few of your stats into this calculator to find out.

  • Ideal Body Weight

    Ideal Body WeightLearn more

    Using body mass index as a reference, this calculator determines your ideal body weight range. All you need to do is enter your height.

  • Body Mass Index

    Body Mass IndexLearn more

    This tool considers your height and weight to assess your weight status.

  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.