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
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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 it is from 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.
Last reviewedAugust 2014by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.