by Scholten A


Hydronephrosis is a backup of urine in one or both kidneys. This leads to swelling and pressure. It needs care right away.


This problem happens when urine cannot drain from the kidney to the bladder. It may be caused by a blockage from:

Urinary Tract Blocked By a Stone
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Risk Factors

Things that may raise the risk of this problem are:

  • Having any of the health problems that cause the condition
  • Cancer treatment
  • Neurogenic bladder


Some people do not have symptoms. Those who do may have:

  • Pain in the back, waist, lower belly, or groin
  • Problems urinating, such as:
    • Pain
    • Urgency
    • Urinating more or less than usual
    • The bladder not feeling emptied
  • Fever
  • Nausea or vomiting


The doctor will ask about your symptoms and health history. A physical exam will be done. You may need to see a doctor who treats kidney diseases.

Blood and urine tests will be done to look for problems with how the kidneys are working.

Images of the kidneys may be taken. This can be done with:

A cystoscopy may also be done. It uses a lighted scope to view the bladder.

Other tests will be done to find a cause.


The cause will need to be treated. This will allow urine to flow as it should. Some options are:

  • Fixing defects in the kidney
  • Removing a kidney stone that will not pass on its own
  • Medicines to treat infection or ease pain
  • Inserting a tube to drain excess urine
  • Taking out of all or part of the kidney (rare)


The risk may be lowered by managing health problems that can harm the kidneys.


National Institute of Diabetes and Digestive and Kidney Diseases  https// 

National Kidney Foundation 


Health Canada 

The Kidney Foundation of Canada 


Hydronephrosis. Cleveland Clinic website. Available at: Accessed December 30, 2020.

Hydronephrosis. National Kidney Foundation website. Available at: Accessed December 30, 2020.

Hydronephrosis. NHS Choices website. Available at: Accessed December 30, 2020.

Nephrolithiasis in adults. EBSCO DynaMed website. Available at: Accessed December 30, 2020.

Nuraj, P and Hyseni, N. The diagnosis of obstructive hydronephrosis with color doppler ultrasound. Acta Inform Med. 2017 Sep; 25(3): 178–181.

Obstructive uropathy. Merck Manual Professional Version website. Accessed December 30, 2020.

Revision Information

  • Reviewer: EBSCO Medical Review Board Adrienne Carmack, MD
  • Review Date: 09/2020
  • Update Date: 12/30/2020