Vesicoureteral reflux (VUR) is a urinary tract condition involving retrograde flow of urine from the bladder into the ureter(s) and collecting system of the kidneys. It is found in up to 2% of children. VUR can increase the risk of urinary tract infections (UTIs) and may lead to renal scarring and, ultimately, reflux nephropathy.

VUR often occurs due to a congenital defect in the valve-like mechanism between the ureters and the bladder, causing urine to move backward into the ureter when the bladder contracts. It may also occur later in life due to bladder dysfunction or neurogenic bladder.

Children with VUR often present with recurrent UTIs, especially upper tract infection (pyelonephritis) presenting with fever, abdominal pain, vomiting, incontinence, and increased urinary urgency and frequency. Some individuals with VUR may be asymptomatic.

VUR is most commonly diagnosed in infants and young children, with 30%-40% of children with UTIs found to have VUR. It affects both sexes, although VUR is more common in children assigned at birth as female.

VUR is classified into 5 grades based on severity, ranging from grade 1 (mild) to grade 5 (severe) based on how extensive reflux into the kidneys becomes.

Timeline and progression of VUR varies widely among different individuals, with some VUR patients resolving quickly and others requiring intervention.

Congenital urinary tract anomalies such as bladder dysfunction or ureterovesical junction abnormalities can predispose someone to develop VUR. A family history of VUR can increase the risk of developing the condition as well. Fifteen percent of infants with in utero hydronephrosis may have VUR.