Characteristics of primary vesico-ureteral reflux in Thai children

The purpose of the present paper was to evaluate the clinical features of primary vesico-ureteral reflux (VUR) in Thai children.

Children with primary VUR attending in the Nephrology Division, Department of Pediatrics, Prince of Songkla University between 1987-2002 were studied.

Sixty-five girls and 60 boys with primary VUR were evaluated. Age of diagnosis was significantly younger in boys than girls (median 0.6 and 2.2 years respectively, P < 0.001). In 73% of boys and 34% of girls VUR diagnosis was made in the first year of life. Hydronephrosis was found in 22% of boys and 8% of girls (P = 0.004). Five per cent of children who had VUR grades I-III had hydronephrosis (6/121). Only children who had VUR grades IV and V had significant hydronephrosis: 33% (14/42) and 53% (10/19), respectively. Bilateral VUR was 60% overall and was significantly more common in boys (70% vs 40% P < 0.028), found in grades I-V at 33%, 61%, 60%, 65%, and 77%, respectively. Of 200 refluxing ureters, the total numbers of VUR grades I-V were 32, 37, 67, 45 and 19 respectively. VUR grade was significantly different by age (P = 0.014) but not by left-right side or sex.

Primary VUR occurs equally in boys and girls, but in boys at a younger age. Bilateral VUR and hydronephrosis were significantly more common in boys, and VUR in boys was more severe. But hydronephrosis is a poor indicator for VUR screening even in high-grade VUR.