Background: The management of young febrile infants with UTIs is marked by uncertainty and variation. Although recent studies have demonstrated the safety and efficacy of oral antibiotics as primary treatment in infants younger than six months of age, younger infants tend to receive a longer duration of intravenous antibiotics. This might reflect a lack of clear delineation of the risk of adverse events and bacteremia in this population.
Study design: Retrospective chart review.
Setting: Twenty primarily tertiary-care EDs.
Synopsis: Infants aged 29 to 60 days with febrile UTIs were identified through laboratory and chart review at the participating centers. Bacteremia and adverse events (death, shock, bacterial meningitis, intensive care, surgical intervention, or other substantial clinical complications) were identified, as well as patients with a high-risk past medical history (PMH) or who were clinically ill on examination, based on a priori definitions of chart wording.
Adverse events occurred in 2.8% of the 1,895 patients; bacteremia occurred in 6.5%. Recursive partitioning analysis was used to identify a very-low-risk population for adverse events—those who were not clinically ill and without high-risk PMH (prediction model sensitivity 98% and negative predictive value 99.9%)—but it was not as successful in accurately identifying infants at very low risk for bacteremia.
Limitations of this study include the lack of a clear description of the adverse events identified (and their presumed relationship to the UTIs), the reliance on ED documentation, and conservative definitions of bacterial meningitis. Nonetheless, this is a study of significant magnitude in a population marked by uncertainty. Results of this study further strengthen data that support the feasibility of outpatient antibiotic therapy in well-appearing infants.
Bottom line: Well-appearing infants aged 29-60 days and without significant past medical history are at very low risk for adverse events.
Citation: Schnadower D, Kupperman N, Macias CG, et al. Febrile infants with urinary tract infections at very low risk for adverse events and bacteremia. Pediatrics. 2010;126:1074-1083.