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Vesicoureteral reflux



Normally, urine flows from the kidneys, down through tubes known as ureters, to the bladder. The ureters enter the bladder in such a way that urine can enter the bladder, but it can't back up from the bladder into the ureters.

In vesicoureteral reflux (VUR), the ureter doesn't grow long enough during prenatal development and it enters the bladder abnormally. As a result, urine can back up, or reflux, from the bladder into one or both ureters and, in severe cases, up into the kidneys.

The condition may improve or disappear as the child gets older and the ureters grow longer.

VUR can also be caused by reasons not related to anatomy, such as voiding problems or problems with nerve tissue in the bladder. Children with this kind of VUR may be given different treatment.

VUR is found in 20 to 50 percent of children who have had a urinary tract infection, and it's twice as common in girls as in boys.

If VUR isn't treated, any bacteria that's in the bladder may reach the kidney. This can cause a kidney infection, which may in turn lead to kidney scarring and damage. Antibiotics are needed to prevent an infection, and if they don't work, surgery may be necessary.

About 40 percent of siblings of kids with VUR also have reflux, with younger siblings being more likely to have it than older ones. Many siblings with VUR have no history of urinary tract infection symptoms, although evidence of infection may be found on investigation. If your child is found to have VUR, we recommend screening younger siblings for the condition as well.


It's especially important to promptly diagnose and treat VUR in infants and small children, since without treatment most of them will develop another urinary tract infection. Waiting until a child has had two or more urinary tract infections before having an evaluation increases the risk of permanent kidney damage or scarring.

Vesicoureteral reflux is usually diagnosed in one of two ways. Children who have a urinary tract infection that's been confirmed by a lab test will have an X-ray evaluation called a voiding cystourethrogram. During the test, the bladder is filled with contrast material that shows up on X-rays. If the child has VUR, the contrast material will backflow into the ureter and kidneys.

Alternately, VUR may be suspected when a prenatal ultrasound reveals that the fetus has dilated kidneys. If this occurs, a voiding cystourethogram is done soon after the birth of the baby.

Other tests may include:

  • Kidney and Bladder Ultrasound — This test is routinely recommended prior to the voiding cystourethrogram. It provides an outline of the kidneys, ureters and bladder, and we use it to look for less common urinary tract defects that can cause urinary tract infections or kidney dilation. The test doesn't require radiation and is painless.
  • Kidney (Renal) Scan — A kidney scan may be performed if the above tests are abnormal or if your child has repeated, fever-causing infections. A kidney scan shows the actual function and drainage of the kidneys, and it can also reveal if there's kidney damage or scarring from a previous urinary tract infection.
  • Nuclear Cystogram — This test is very similar to the voiding cystourethrogram, but it involves less radiation and is very sensitive for reflux. The voiding cystourethrogram is the preferred test for initially diagnosing reflux, because it provides a clearer picture of the lower urinary tract and therefore can rule out other less common abnormalities, as well as grade the severity of the reflux. Once the diagnosis has been made by the voiding cystourethrogram, the nuclear cystogram is the recommended follow-up test. The nuclear cystogram is also used to screen siblings of children who have reflux to determine if they also have the condition.

Reflux is graded on a scale of one to five, with one being a mild form and five being severe. The degree of reflux is used to make decisions on how to treat the child. More severe grades are less likely to clear up spontaneously and more likely to cause kidney damage if they're not treated.


Vesicoureteral reflux, or VUR, is treated either with medication or surgery, depending on the severity of the reflux, the child's age, the number and severity of urinary tract infections and the amount of kidney damage seen on X-ray studies.

Treatment always includes a low daily dose of antibiotics. These antibiotics are very specific for the urinary tract and have very few side effects. The goal is to prevent kidney infections until the reflux goes away or is corrected. The type of antibiotic we use will depend on your child's age and allergies.

Medical Therapy

Because many cases of reflux resolve on their own as the child grows, medical therapy may be all that's needed. Medical therapy entails using antibiotics to prevent infection until the condition resolves, and monitoring your child to make sure it does resolve.

Children receiving medical therapy will take a small dose of antibiotics every day. An ultrasound and cystogram will be done annually to assess the kidneys and see if the reflux has resolved. If the reflux persists for several years without improvement, surgery may be considered. If your child continues to have fever-causing urinary tract infections despite taking antibiotics, then surgery should be considered. Again, the goal is to prevent scarring or damage from a kidney infection.

Surgical Therapy

Surgery would be performed if your child has more severe reflux, fever-causing urinary tract infections despite being on antibiotics, and signs of kidney damage due to repeated infections. Surgery may also be discussed when, after giving time for the condition to go away as the child grows, repeated voiding cystourethrograms show that the reflux doesn't appear to be improving.

In the surgical procedure, the refluxing ureter is repositioned or re-implanted in the bladder wall. The end of the ureter is surrounded by bladder muscle in this new position in the bladder, which prevents urine from "backing up" or refluxing toward the bladder.

Your child will be in the hospital for three to four days. After the surgery, your child will still need to take antibiotics daily until the bladder and ureter are healed. An ultrasound will be performed about a month after surgery and, depending on the case, a voiding cystourethrogram may be performed six months following surgery.

UCSF Benioff Children's Hospitals medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your child's doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your child's provider.

Where to get care (1)

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Vesicoureteral Reflux Center

Vesicoureteral Reflux Center

San Francisco / Oakland / Greenbrae / Modesto / San Mateo / Walnut Creek

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