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Hydronephrosis (Swollen Kidneys)

Hydronephrosis, or swollen kidneys, is a urological condition where the kidney urinary collecting system is dilated. . Hydronephrosis is not a disease, but it can be caused by a number of conditions which affect the kidney and the urinary tract. If left untreated, the pressure of the built-up urine which normally flows easily through the urinary tract may  cause pain, swelling and permanent damage to the kidneys. It is important to seek help if you experience this condition, since untreated hydronephrosis can lead to permanent loss of kidney function, a life-threatening condition.

Hydronephrosis may be unilateral, involving one kidney, or bilateral, involving both. It is closely related to hydroureter, or swelling of the ureter, and often coincides or causes this condition.


The symptoms of hydronephrosis will vary depending on how long you have had the obstruction, but will likely include some or all of the following:

  • Tenderness or pain in abdomen or side of torso
  • Nausea and vomiting
  • Fever

For women, one of the most common symptoms of a swollen kidney or hydronephrosis is a urinary tract infection, or UTI. Common symptoms of a UTI, in addition to frequent and painful urination mentioned above, would also include:

  • Cloudy urine
  • Blood in urine
  • Fever
  • Back pain

Hydronephrosis, and UTIs as well, are potentially very serious conditions which can lead to other complications, such as kidney infection or blood poisoning, if left untreated. Please schedule an appointment with Skyline Urology if you are experiencing these symptoms, and let us help you with sophisticated diagnostic procedures and integrated treatment to help you back to health.


One of the most common causes of hydronephrosis is blockage of the ureter which connects the kidney to the bladder. A kidney stone is often the cause of this blockage, but it could also be caused by scarring and blood clots as well.  The blockage, regardless of the underlying cause, results in the urine not being able to drain out of the kidney building up in the kidney.

Other common causes of hydronephrosis include:

  • Tumors near or in the ureter
  • Congenital narrowing of the ureter
  • Injury to the kidney or ureter, especially one affecting the ureteropelvic junction (UPJ) which connects the ureter to the kidney
  • Blockage of the bladder

Evaluation & Diagnosis

Diagnosis of hydronephrosis as early as possible is extremely important to avoid permanent damage to the kidneys which could have devastating and long-lasting effects. Your Skyline Urology physician will most likely begin with a detailed physical examination and get your complete medical history, along with any medications you are currently taking.

Diagnostic testing to detect hydronephrosis is usually performed using ultrasound technology, as it is a painless procedure for the patient and allows an accurate picture of the kidney to detect swelling. Also helpful are CT scans, to gain a visual image of the affected organ and urinary tract.

If indicated, you may undergo a nuclear renal scan which allows the physician to better gauge the amount of obstruction. In this procedure an  injection of a nuclear isotope is given into the blood stream. A specialized camera outside the body tracks the isotope through the kidneys and bladder in order to determine the function of the kidney and the flow of urine.


Treatment for hydronephrosis will be focused on elimination or removal of whatever is causing the obstruction, so that the urine can flow freely again and the kidneys can achieve maximum function. Depending on the cause of your obstruction, your Skyline Urology physician will customize a treatment plan which resolves the issue, either through medication or sophisticated procedures which are advanced and clinically effective.

Skyline Urology offers the following therapeutic solutions to hydronephrosis:

  • Ureteral stent opening up the ureter passageway to allow unimpeded urine flow
  • Nephrostomy tube which creates an alternate urine drainage path in the back of the kidney
  • Antibiotics to control infection
  • Removal of scar tissue, kidney stone, or blood clot through endoscopic surgery 
  • Robotic surgery to reconstruct  the urinary system