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Condition 101 About Hydronephrosis

What is the definition of Hydronephrosis?

Hydronephrosis is swelling of one kidney due to a backup of urine. This problem may occur in one kidney.

What are the alternative names for Hydronephrosis?

Hydronephrosis; Chronic hydronephrosis; Acute hydronephrosis; Urinary obstruction; Unilateral hydronephrosis; Nephrolithiasis - hydronephrosis; Kidney stone - hydronephrosis; Renal calculi - hydronephrosis; Ureteral calculi - hydronephrosis; Vesicoureteral reflux - hydronephrosis; Obstructive uropathy - hydronephrosis

What are the causes for Hydronephrosis?

Hydronephrosis (kidney swelling) occurs as the result of a disease. It is not a disease itself. Conditions that may lead to hydronephrosis include:

  • Blockage of a ureter due to scarring caused by prior infections, surgeries, or radiation treatments
  • Blockage from an enlarged uterus during pregnancy
  • Birth defects of the urinary system
  • Back flow of urine from bladder to kidney, called vesicoureteral reflux (may occur as a birth defect or due to an enlarged prostate or narrowing of the urethra)
  • Kidney stones
  • Cancers or tumors that occur in the ureter, bladder, pelvis or abdomen
  • Problems with the nerves that supply the bladder

The blockage and swelling of the kidney may occur suddenly or may develop slowly.

What are the symptoms for Hydronephrosis?

Common symptoms include:

  • Flank pain
  • Abdominal mass, especially in children
  • Nausea and vomiting
  • Urinary tract infection (UTI)
  • Fever
  • Painful urination (dysuria)
  • Increased urinary frequency
  • Increased urinary urgency

In some cases, there may be no symptoms.

What are the current treatments for Hydronephrosis?

Treatment depends on the cause of the kidney swelling. Treatment may include:

  • Placing a stent (tube) through the bladder and ureter to allow urine to flow from the kidney into the bladder
  • Placing a tube into the kidney through the skin, to allow the blocked urine to drain out of the body into a drainage bag
  • Antibiotics for infections
  • Surgery to correct the blockage or reflux
  • Removal of any stone that is causing blockage

People who have only one kidney, who have immune system disorders such as diabetes or HIV, or who have had a transplant will need treatment right away.

People who have long-term hydronephrosis may need antibiotics to reduce the risk of UTI.

What is the outlook (prognosis) for Hydronephrosis?

Loss of kidney function, UTI, and pain may occur if the condition is left untreated.

What are the possible complications for Hydronephrosis?

If hydronephrosis is not treated, the affected kidney may be permanently damaged. Kidney failure is rare if the other kidney is working normally. However, kidney failure will occur if there is only one functioning kidney. UTI and pain may also occur.

When should I contact a medical professional for Hydronephrosis?

Call your health care provider if you have ongoing or severe flank pain, or fever, or if you think you may have hydronephrosis.

How do I prevent Hydronephrosis?

Prevention of the disorders that cause this condition will prevent it from occurring.



Frøkiaer J. Urinary tract obstruction. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 37.

Gallagher KM, Hughes J. Urinary tract obstruction. In: Feehally J, Floege J, Tonelli M, Johnson RJ, eds. Comprehensive Clinical Nephrology. 6th ed. Philadelphia, PA: Elsevier; 2019:chap 58.

Top Global Doctors For Hydronephrosis

Latest Advances On Hydronephrosis

Latest Advance
  • Condition: Hydronephrosis by Retroperitoneal Fibrosis
  • Journal: Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences
  • Treatment Used: Corticosteroid-Based Therapy with Surgical Intervention
  • Number of Patients: 17
  • Published —
This study investigated the clinical outcomes of patients with hydronephrosis that was caused by retroperitoneal fibrosis.
Latest Advance
  • Condition: Primary Obstructive Megaureter (POM)
  • Journal: La Pediatria medica e chirurgica : Medical and surgical pediatrics
  • Treatment Used: High-pressure Balloon Dilatation
  • Number of Patients: 30
  • Published —
The study researched the safety and effectiveness of high-pressure balloon dilatation for children with primary obstructive megaureter.

Clinical Trials For Hydronephrosis

Clinical Trial
  • Status: Not yet recruiting
  • Intervention Type: Diagnostic Test
  • Participants: 300
  • Start Date: February 1, 2021
Diagnostic Imaging of Acute Pyelonephritis - Part of the INDEED Study (Infectious Diseases in Emergency Departments)
Clinical Trial
  • Status: Not yet recruiting
  • Phase: N/A
  • Intervention Type: Combination Product
  • Participants: 93
  • Start Date: August 2019
Instillation of Renal Pelvis With 0.5% Iodophors for Patients With Calculous Pyonephrosis for I-stage PCNL : a Multicentre, Prospective, Open, Randomized Clinical Trial