Risk of Bacteremia for Febrile Young Children in the Post–Haemophilus influenzae Type b Era

Abstract

Objectives To determine the risk for bacteremia, in the post–Haemophilus influenzaetype b era, in a prospective cohort of well-appearing febrile children 3 to 36 months of age with no obvious source of infection; and to compare the predictive abilities of objective criteria in identification of children with occult pneumococcal bacteremia from those at risk. Design All children seen from 1993 through 1996, 3 to 36 months of age with a temperature of 39.0°C or higher, no identified source of infection (except otitis media), and discharged to home were considered to be at risk for occult bacteremia and included in the study. Setting Urban pediatric emergency department. Results Of 199868 patient visits to the emergency department, 11911 children were considered to be at risk for occult bacteremia. Blood cultures were obtained from 9465 (79%). A total of 149 blood cultures contained pathogenic organisms, indicating a rate of occult bacteremia of 1.57% (95% confidence intervals: 1.32%-1.83%). White blood cell count and absolute neutrophil count were the best predictors for occult pneumococcal bacteremia. Using a white blood cell count cutoff value of 15 cells × 10⁹/L (sensitivity, 86%; specificity, 77%; and positive predictive value, 5.1%) would result in the treatment of approximately 19 nonbacteremic children for each bacteremic child treated. Conclusions The prevalence of occult bacteremia in children 3 to 36 months old with temperatures of 39.0°C or higher and no obvious source of infection is 1.6%. The white blood cell and absolute neutrophil counts are the most accurate predictors of occult pneumococcal bacteremia and when available should be used if presumptive antibiotic therapy is being considered.