The aim of this study was to evaluate the usefulness of
procalcitonin (PCT) as a marker of renal
scars in infants and young children with a first episode of acute
pyelonephritis. Children aged 7 days to 36 months admitted for first febrile
urinary tract infection (UTI) to a pediatric emergency department were prospectively enrolled. The PCT concentration was determined at admission. Acute (99m)Tc-dimercaptosuccinic
acid (
DMSA) scintigraphy was performed within 7 days of admission and repeated 12 months later when abnormal findings were obtained on the first scan. Of the 72 children enrolled in the study, 52 showed signs of acute
pyelonephritis (APN) on the first
DMSA scan. A follow-up scintigraphy at the 12-month follow-up performed on 41 patients revealed that 14 (34%) patients had developed renal
scars; these patients also presented significantly higher PCT values than those without permanent renal lesions [2.3 (interquartile range 1-11.6) vs. 0.5 (0.2-1.4) ng/mL; p = 0.007]. A comparison of the PCT concentration in patients with febrile UTI without renal involvement, with APN without
scar development and with APN with subsequent renal
scarring revealed a significant increasing trend (p = 0.006, Kruskal-Wallis test). The area under the ROC curve for
scar prediction was 0.74 (95% confidence interval 0.61-0.85), with an optimum statistical cut-off value of 1 ng/mL (sensitivity 78.6%; specificity 63.8%). Based on these results, we suggest that serum PCT concentration at admission is a useful predictive tool of renal
scarring in infants and young children with acute
pyelonephritis.