Overview. Vesicoureteral reflux (VUR) occurs when urine stored in the bladder flows back up into the ureters (the tubes that carry urine down from the kidneys to the bladder), and often back up into the kidneys. This can cause hydronephrosis (swelling of the kidney) and kidney damage. It is particularly common in children, usually caused by a congenital abnormality and often diagnosed during a prenatal ultrasound or when the infant or child has a urinary tract infection (UTI). VUR is discovered in approximately one in three children diagnosed with a UTI. When not treated through either antibiotic therapy or, when necessary, surgery, VUR can allow bacteria that grow in urine to enter the kidneys, which can lead to kidney infection, kidney damage, and chronic kidney failure.
Types. In a normal urinary tract, the kidneys filter waste products from the bloodstream and produce urine, which drains down the ureters to the bladder to be stored until it is emptied from the body through the urethra. As the ureter makes a tunnel through the bladder wall, a “flap valve” is created to prevent urine in the bladder from backing up and returning to the ureter. In VUR, the flap valve at the junction of the ureter and the bladder is abnormal, causing some of the urine to go back up.
In cases of primary VUR, the child is born with a faulty valve – usually either because the ureter is too short for the valve to close properly, or because the ureter is inserted abnormally into the bladder. Often, the reflux will resolve itself as the child grows, though sometimes intervention is necessary. In secondary VUR, a UTI or obstruction somewhere in the urinary tract is responsible.
Symptoms. UTI is the most common symptom of VUR, particularly in young children. For older children, symptoms can include nocturnal enuresis (bedwetting) or other urinary problems, high blood pressure, hydronephrosis, an abdominal mass from the swollen kidney, protein in the urine, and kidney failure.
Diagnosis. The two most common diagnostic tests for VUR are a voiding cystourethrogram (VCUG), which examines the urinary tract through X-ray images as the bladder fills and empties; and a renal ultrasound, which produces sound waves to transmit a picture of the kidney and bladder that can reveal abnormalities. Based on these tests, the severity of the reflux is graded, with grade 1 being the most mild and grade 5 being the most severe. Higher-grade reflux is less likely to get better without treatment.
Treatment. Children who are expected to outgrow their reflux are followed closely and monitored with VCUG, renal ultrasound, and other tests. Even when surgery isn’t required, antibiotics are needed to prevent or immediately treat infections in order to ensure that there is no kidney damage. When the reflux is severe enough that infection can’t be controlled by antibiotics, surgery may be needed. The surgical approach usually involves either severing and then reattaching the ureter to the bladder to make a longer tunnel or create a new angle, or using a bulking agent (inserted through a telescope) to strengthen the flap valve.