Hydronephrosis: Causes

What causes hydronephrosis?

Hydronephrosis is caused by a variety of underlying diseases, disorders or conditions that obstruct or slow the flow of urine though the ureter, bladder or urethra. Hydronephrosis can also be caused by certain conditions that result in backflow of urine into the kidney. Causes include:

• Bladder stone or tumors that block the flow of urine from the bladder, causing urine to back up into the ureters and kidneys

• Blood clot

• Congenital narrowing of the ureters or the ureter valves

• Enlarged prostate

• Kidney stone

• Neurogenic bladder (bladder that does not empty due to nerve damage)

• Pregnancy

• Tumor or cancer of the ureter that presses and impinges on the ureter. A tumor or cancer of the uterus, intestine, or other area can also press on the ureter.

• Ureter scarring due to injury or surgery

• Ureteropelvic junction obstruction (UPJ, a blockage in the area where the kidney connects to the ureter; UPJ can be present at birth or caused by scarring due to infection, kidney stone, or surgery)

• Urethral stricture (scarring of the urethra, which can block the flow of urine from the bladder, causing urine to back up into the ureters and kidneys)

• Vesicoureteral reflux (condition in which urine flows backward up the ureters and into the kidney)

What are the risk factors for hydronephrosis?

A number of factors increase the risk of developing hydronephrosis. Risk factors include:

• Blood clotting disorders

• Cancer in the pelvic or lower abdominal area

• Enlarged prostate

• Frequent urinary tract infections

• Neurogenic bladder (damaged bladder nerves)

• Pregnancy

• Urinary tract or pelvic organ surgery

Reducing your risk of hydronephrosis

Not all people who are at risk for hydronephrosis will develop the condition. However, you can lower your risk of developing hydronephrosis by seeking prompt medical care for urinary symptoms, such as frequent urination, painful urination, and difficulty urinating.