Imaging studies are part of standard care following urinary tract infections (UTI) in young children. Dimercaptosuccinic (DMSA) acid and glucoheptonate renal scans have been widely recommended to identify both the presence of acute pyelonephritis (APN) and renal scarring, although the long-term clinical consequences of either event in children with anatomically normal urinary tracts is unknown. Furthermore, some authorities recommend antimicrobial prophylaxis for those with scintigraphic evidence of parenchymal damage despite the lack of data supporting its efficacy. As part of an ongoing clinical trial evaluating oral vs. intravenous therapy for a first episode of UTI, 179 children aged 1-24 mos. with fever (≥38.3° C) had a DMSA or glucoheptonate scan within 48 hours of diagnosis and a repeat scan 6 months later. Renal scans performed at the time of infection showed parenchymal inflammation in 137 (77%) of 179 patients. 134 patients completed the 6-month follow-up; 90 (67%) had normal scans and 44 (33%) showed renal scarring. Sera were obtained at the time of infection and one month later in the 21 most recently enrolled patients. Antibody titers against formalin-killed (FK)E. coli and lipopolysaccharide (LPS) were measured. A two fold increase in either of the two antibody levels was considered a positive response. Results are shown. Table

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The sensitivity, specificity, positive and negative predictive values of a positive antibody response at one month for the presence of renal scarring six months later were 83.3%, 80%, 62.5% and 92.3%, respectively. If further observations confirm these findings, measurement of antibody titers to FKE. coli and LPS soon after an episode of APN may provide a more timely and less costly identification of renal scarring than routine use of renal scintigraphy.