Hydronephrosis occurs when urine builds up in the kidneys and cannot drain out to the bladder. The kidneys swell from the excess urine. The condition may affect one kidney or both. Hydronephrosis is not a disease itself. It is a sign of another disease or condition affecting the kidneys.
Kidney, Ureter, Bladder, and Kidney Stone
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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 birthKidney stonesA blood clotScarring of the ureters, which are the tubes that connect the kidneys to the bladderA tumor in the pelvic area such as the bladder, cervix, colon, or prostateEnlarged prostateEnlarged uterus during pregnancy
in the kidneys
Neurogenic bladderInjury to structures in the urinary system, such as from surgery or trauma
The following factors increase your chances of developing hydronephrosis: Defect in the urinary system that is present at birthCancers
in the pelvic area
Pelvic surgeryBlood-clotting disordersRecurrent urinary tract infectionsEnlarged prostateNeurogenic bladderPregnancy
Hydronephrosis may or may not cause any symptoms.
If symptoms occur, they may include: Pain in the back, waist, lower abdomen, or groinPersistent pain with urination or urinary frequency from urinary tract infectionsIncreased urge to urinate or urinary incontinenceIncomplete urinationFeverNausea and vomitingUnexplained itching
Your doctor will ask about your symptoms and medical history. A physical exam will be done. It may involve examination of the pelvis or rectum to feel for blockages. You will likely be referred to an urologist and/or nephrologist for further diagnosis and treatment.
Your bodily fluids may be tested. This can be done with: Urine testsBlood testsBladder catheterization
Your internal structures may need to be viewed. This can be done with: Abdominal ultrasoundIntravenous urogramComputed tomography angiography (CTA)MRI scanCystoscopyVoiding cystourethrogram
Treatment involves: Draining excess urine from the kidneyRemoving the blockageTreating conditions that cause blockage or refluxTreating infections in the urinary system
Some causes of hydronephrosis resolve without treatment, such as pregnancy and
Treatment options include: Antibiotics to treat urinary tract infectionsMedications to treat neurogenic bladder or to reduce excess uric acid excretionCatheter inserted into the bladder to drain the urineNephrostomy—a tube inserted into an opening in the midsection to drain urine from the kidneySurgery to remove a blockage or correct a defect in the urinary systemSurgery
to remove part or all of the kidney—rare
In general, the causes of hydronephrosis cannot be prevented. Prompt treatment of conditions that cause hydronephrosis reduces the risk of complications, such as
Kidney disease and kidney failure. National Kidney and Urologic Disease Information Clearinghouse website. Available at:
http://kidney.niddk.nih.gov/kudiseases/topics/failure.asp. Updated November 15, 2012. Accessed July 12, 2013.
Your child has hydronephrosis. National Kidney Foundation website. Available at:
http://www.kidney.org/atoz/content/hydronephrosis.cfm. Accessed July 12, 2013.
Last reviewed May 2014 by Adrienne Carmack, 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.
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