Urine normally passes from kidneys down the ureters and into the urinary bladder. The muscles of the bladder and ureters, along with the pressure of urine in the bladder, prevent urine from flowing backward through the ureters.

The bladder is an elastic muscle that acts as a storage tank. As the bladder fills, its walls relax to hold more urine, and the control (sphincter) muscle remains tight to prevent leakage of urine. Urine is prevented from going back up the ureters toward the kidneys by a valve where the ureters and bladder meet, but when the valve is inadequate it allows urine to flow back up into the ureters, causing this reflux condition.

About one out of three children who have urinary tract infections are found to have reflux. Reflux is a condition people are born with and it tends to run in families. If your child has reflux, other siblings may have an increased risk of having reflux, depending on the age of the sibling.

Most urinary tract infections stay in the bladder. When a child has reflux, the bacteria have direct access to the kidneys and cause a kidney infection. This can result in damage to the kidneys, and, in some other children, early onset of hypertension.


The diagnosis of reflux is made by a bladder X-ray called a voiding cystourethrogram (VCUG). During the test a small tube is put into the urethra and a fluid (contrast media or isotope) flows into the bladder. X-ray pictures are then taken to check for reflux.

If your child has reflux, then further tests will be administered to check how well the kidneys are working and to look for kidney damage. Kidney size will also be checked to follow future renal growth and to observe for scarring.


The plan of treatment will vary according to your child’s age, number of urinary tract infections and X-ray findings. Reflux is "graded" on a scale of one through five: one is the mildest and five is the most severe.

In children with mild to moderate grades of reflux (grades 1-3) there is an excellent chance that the reflux will disappear as the child gets older and the ureteral valve matures.

For treatment, children are given a low dose of an antibiotic nightly for as long as the child has reflux; have urine cultures done on a regular basis; undergo VCUG every 12 to 18 months to check if reflux has disappeared; and have a sonogram of the kidneys to check for growth every one to two years.

Children with higher grades of reflux typically need surgery to correct the condition. This type of surgery is highly successful and safe.