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.
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.
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.
Reviewed by health care specialists at UCSF Benioff Children's Hospital.