The true incidence of vesicoureteral reflux (VUR) is unknown, but it is thought to be less than 1%. There are two distinct groups of patients who present with VUR: 1) patients who are discovered to have VUR in the course of a workup of a febrile UTI, who tend to be more often be girls than boys; and 2) patients with antenatally diagnosed hydronephrosis, who tend to be more often be boys than girls. The incidence of VUR in those groups are 30-40% and 10%, respectively. There is a genetic predisposition to having VUR, with the sibling concordance being 30-50%.1

There are two kinds of VUR: primary and secondary. The primary VUR is due to an anatomic abnormality of the vesicoureteral junction. Normally, the ureter inserts into the wall of the bladder in a slanted fashion, with the musculature around the insertion functioning more or less like a valve. In primary VUR, the ureter inserts in a more horizontal fashion, with the “valve” now dysfunctional due to the abnormal insertion. Secondary VUR is caused by primary bladder pathology or dysfunction (such as cystitis or neurogenic bladder).(1)

VUR is graded (radiologically) as follows(1):
Grade 1: the contrast only refluxes into a normal caliber ureter.
Grade 2: the contrast fills an undilated ureter and the pyelocalyceal system, forming a cast of the normal collecting system.
Grade 3: the contrast shows mild dilation of the ureter and the pelvis. The sharp angles on the fornix of the calyx are blunted.
Grade 4: the contrast shows moderate dilation of the ureter and pelvis, and the calyceal anatomy is distorted sufficiently to provide only a papillary impression.
Grade 5: the contrast reveals severe dilation and tortuosity of the ureter, severe dilation of the pelvis, and clubbed calyces with no papillary impression.

Grading of an isotope cystogram ( by attempting to use the radiological criteria) is often inaccurate. It is probably best to simply describe the pattern observed on the images.

The principal management consists of antibiotic prophylaxis to prevent infection and possible scarring. Note that sterile reflux in and of itself does not cause scarring. Surgical treatment of VUR is sometimes indicated.(2)