Afebrile Infants Evaluated in the Emergency Department for Serious Bacterial Infection.

Objectives: Afebrile infants 0 to 60 days of age are sometimes evaluated for serious bacterial infection (SBI). Our objective was to describe the clinical and laboratory findings in this population and compare them to their febrile counterparts.

Methods: We performed a retrospective observational study comparing afebrile infants undergoing an SBI evaluation to those evaluated for fever.

Results: We included infants who were admitted to the hospital and had at least 2 of 3 following bacterial cultures: blood, urine, or cerebrospinal fluid. Of the 1184 infants presenting to the emergency department with chief complaints that may prompt an SBI evaluation, 579 patients met our inclusion criteria with 362 in the fever group and 217 in the afebrile group. The most common chief complaints in the afebrile group were respiratory symptoms (27%), seizure (22%), vomiting/diarrhea (21%), and apparent life-threatening event (11%). Rates of true-positive blood, urine, and cerebrospinal fluid cultures were 2%, 2.4%, and 0.9% respectively. All cases of bacterial meningitis were in the fever group antibiotics (P = 0.16). Infants with fever were more likely to receive antibiotics (P < 0.001), although there were no statistical differences between the 2 groups in the rates of positive blood or urine cultures.

Conclusions: Afebrile infants make up a significant percentage of SBI evaluations in the emergency department. Respiratory symptoms, vomiting, and seizure-like activity are common presentations. Although rates of bacteremia and urinary tract infection are higher in the febrile group, this did not reach statistical significance, and therefore afebrile infants should still be considered at risk for SBI.