Health Information For Parents

A to Z: Hydronephrosis

Content

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.

Translation

Resources

  • National Kidney Foundation (NKF)

    NKF seeks to prevent kidney and urinary tract diseases, improve the health and well-being of individuals and families affected by these diseases, and increase the availability of all organs for transplantation.

  • American Academy of Family Physicians

    This site, operated by the American Academy of Family Physicians (AAFP), provides information on family physicians and health care, a directory of family physicians, and resources on health conditions.

  • American Academy of Pediatrics (AAP)

    The AAP is committed to the health and well-being of infants, adolescents, and young adults. The website offers news articles and tips on health for families.

  • Nephron Information Center

    The Nephron Information Center offers information about how the kidneys work, transplants, and links to other sites.

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