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Home > Services > Kidney Care > Kidney Conditions > Hydronephrosis



Hydronephrosis occurs when urine builds up in the kidneys and cannot drain out to the bladder. This causes one or both kidneys to swell.

Two urinary system problems cause hydronephrosis:

  • A blockage may prevent urine from draining out of the kidneys.
  • A condition known as reflux may cause urine to flow back into the kidneys from the bladder.

These problems may in turn result from:

  • A congenital blockage or defect in the urinary system
  • Kidney stones
  • A blood clot
  • Scarring of the ureters
  • A tumor in the pelvic area such as the bladder, cervix, colon or prostate
  • Enlarged prostate
  • Enlarged uterus during pregnancy
  • Persistent urinary infection in the kidneys
  • Neurogenic bladder
  • Injury to structures in the urinary system, such as from surgery or trauma

Symptoms of Hydronephrosis

If symptoms occur, they may include:

  • Pain in the back, waist, lower abdomen or groin
  • Persistent pain with urination or urinary frequency from urinary tract infections
  • Increased urge to urinate or urinary incontinence
  • Incomplete urination
  • Fever
  • Nausea and vomiting
  • Unexplained itching

Diagnosing Swollen Kidneys

Your doctor may examine your pelvis or rectum to feel for blockages. Your doctor may also want to test your bodily fluids and internal structures. 

This can be done with:

  • Urine tests
  • Blood tests
  • Bladder catheterization
  • Abdominal ultrasound
  • Intravenous urogram
  • Computed tomography angiography (CTA)
  • MRI scan
  • Cystoscopy
  • Voiding cystourethrogram

Treatment for Hydronephrosis

Treatment involves:

  • Draining excess urine from the kidney
  • Removing the blockage
  • Treating conditions that cause blockage or reflux
  • Treating infections in the urinary system

Some causes of hydronephrosis resolve without treatment, such as pregnancy and kidney stones.

Treatment options include:

  • Antibiotics to treat urinary tract infections
  • Medications to treat neurogenic bladder or to reduce excess uric acid excretion
  • Bladder catheter to drain the urine
  • Nephrostomy — a tube in your midsection that drains urine from the kidney
  • Surgery to remove a blockage or correct a defect in the urinary system
  • Surgery to remove part or all of the kidney


Call 434.243.3675


Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.

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