Hydronephrosis is the result of a problem in the urinary tract. Urine drains from the kidneys into the bladder. With hydronephrosis, urine backs up into the kidneys causing a buildup of pressure.

Urinary Tract Blocked By a Stone
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Causes of hydronephrosis:

  • Kidney stones
  • Blood clots
  • Growths or tumors
  • Scarring—can happen from an accident or surgery
  • An enlarged prostate
  • Urine can't drain into the bladder
  • Bladder is not draining well
  • Pregnancy

Risk Factors

Your risk is higher if you have:


Some people don't have symptoms. If symptoms appear, they may cause:

  • Pain in the back, waist, lower belly, or groin
  • Problems related to urination:
    • Pain
    • Urgency
    • Lower output
    • Cycles of lower and higher output
    • Bladder not feeling emptied out
  • Fever
  • Nausea or vomiting


The doctor will ask about your symptoms and health history. You may also have:


The goal of care is to treat the cause. This will help ease pressure and limit further problems.

Care may involve:

  • Fixing structural defects
  • Treating a kidney stone
  • Placing a stent—a tube is used to keep a passage open
  • A tube is placed into the kidney to drain urine— nephrostomy
  • Taking out of all or part of the kidney (rare)— nephrectomy


If you have problems with your kidneys, getting prompt care will lower your chances of complications.

Revision Information

  • Reviewer: EBSCO Medical Review Board Adrienne Carmack, MD
  • Review Date: 05/2018 -
  • Update Date: 06/05/2018 -