Urine flows from the kidneys to the bladder via a muscular tube called the ureter. Under normal circumstances the ureter enters the bladder in a way that when the bladder squeezes urine out it pinches the ureter closed and prevents urine from refluxing back to the kidney. Sometimes, however, the ureter enters the bladder in an abnormal way and urine in the bladder refluxes back to the kidney. This urinary reflux is not harmful to the kidney but recycling of urine can predispose to urinary infection; infection in the kidney can cause high fever and sometimes scarring of the kidney tissue.
VUR is diagnosed by a test called a voiding cystourethrogram (VCUG). A VCUG is done either because a prenatal ultrasound showed a particular type of kidney abnormality or because a young child (usually under age 2 years) has had one or more urinary tract infections. The VCUG requires a catheter be placed through the urethra into the bladder; the urine is drained and then filled with a dye that looks like water and x-ray pictures are taken of the bladder and urinary tract during voiding.
VUR is graded 1 through 5 and can be thought of as mild, moderate, or severe. Even in children with severe VUR the initial approach to treatment is almost always low dose once daily antibiotics to minimize the chance of further infections. For children with mild or moderate VUR additional VCUG testing may not be necessary, and if there have been no additional urinary infections, the antibiotics can often be stopped after 1-2 years as the risk of urinary infections and kidney scarring from urinary infections decreases. However, if a child with mild to moderate VUR has additional infections despite daily antibiotic, or if the reflux is severe, a VCUG will be repeated. Depending upon this result, referral to pediatric urology may be made for consideration of surgery. In these circumstances, surgery may be a good option to prevent additional infections that can cause kidney scarring.
Fortunately, only a small number of children with reflux eventually require surgery. VUR resolves in the majority of circumstances and thus the initial treatment is almost always conservative. This means low dose once daily antibiotics. Many families are worried about giving their child antibiotic daily. Fortunately, side effects at the doses used are rare. In addition, daily low dose antibiotics do not adversely affect a child’s immune system or ability to fight infection. Occasionally bacteria can become resistant to the antibiotic used and urinary infection can occur despite treatment, but this is not a defect in the child’s immune system and the change in the bacteria is not a permanent situation.