Primary and acquired renal scarring in boys and girls with urinary tract infection

Objectives: To determine when pyelonephritic renal scarring was detected in children with urinary tract infection (UTI) and characterize those with pr imary and acquired scarring, respectively. Study design: A population-based cohort of 1221 children (989 girls and 232 boys) with first recognized symptomatic UTI, aged 0 to 15 years, were diag nosed and followed up prospectively at a single children's hospital; 652 ha d febrile UTI. Seven hundred fifty-three were evaluated by urography. Renal scarring was classified as primary or acquired, the latter without signs o f scarring at the first investigation. To evaluate the frequency of recurre nt UTI in those with acquired scarring, a comparison with group-matched chi ldren without scarring was performed. Results: A total of 74 children without obstruction had renal scarring (acq uired in 40). Primary scarring was found in 18 of 21 (86%) of the boys and 16 of 53 (30%) of the girls (P < .001). The majority of boys with scarring had dilated reflux (67%) in contrast to girls (23%). Recurrent UTI was rare in boys, whereas girls with acquired scarring had significantly more febri le recurrences than girls without scarring. Conclusions: Most boys had primary probably congenital, reflux-associated r enal damage, whereas mast girls had acquired scarring related to recurrence s of febrile UTI. (J Pediatr 2000;136:30-4).