Relationship among vesicoureteral reflux, urinary tract infection and renal damage in children

PURPOSE: We studied the relationship among vesicoureteral reflux, urinary tract infection and permanent renal damage in children. MATERIALS AND METHODS: We retrospectively analyzed 303 children younger than 2 years with a first time, nonobstructive, culture verified urinary tract infection. The protocol included ultrasonography and voiding cystourethrography within 3 months after urinary tract infection, and (99m)technetium dimercapto-succinic acid scintigraphy after 1 to 2 years. RESULTS: Vesicoureteral reflux was found in 36 of 163 boys (22%) and in 44 of 140 girls (31%). Of the 303 patients 80 (26%) had permanent renal damage according to dimercapto-succinic acid scintigraphy. The rate of abnormality increased significantly with grade of vesicoureteral reflux in boys and girls. The relative risk of renal damage was significantly increased in patients with vesicoureteral reflux grade II and higher. Maximum C-reactive protein concentration, maximum temperature during urinary tract infection, presence of vesicoureteral reflux and febrile recurrences of urinary tract infection were significantly related to permanent renal damage. In stepwise logistic regression vesicoureteral reflux was the only independent variable for boys, while C-reactive protein and vesicoureteral reflux were independent factors for girls. CONCLUSIONS: There was a significant relationship between grade II vesicoureteral reflux and higher and permanent renal damage in boys and girls. However, while the association between renal damage and vesicoureteral reflux was evident in boys, the role of urinary tract infection and renal inflammation seemed to be equally or more important in girls. These findings support the concept that renal damage is associated with vesicoureteral reflux and is often congenital in boys, while in girls it is more related to urinary tract infection with vesicoureteral reflux as a reinforcing factor.