Factors associated with serious bacterial infections in infants ≤60 days with hypothermia in the emergency department

Background: We sought to investigate risk factors for serious bacterial infection (SBI: bacterial meningitis, bacteremia, and urinary tract infection [UTI]) among infants ≤60 days of age presenting to the emergency department (ED) with hypothermia (temperature < 36 °C). Methods: We performed a single center study over a 12-year period including all patients ≤60 days old with hypothermia, excluding patients who did not receive a blood culture and patients who received antibiotics prior to culture acquisition. The primary outcome was SBI. Secondary outcomes were mortality and herpes simplex infection. We performed multivariable logistic regression to identify risk factors for primary outcomes reporting adjusted odds ratios with 95% confidence intervals (aOR, 95% CI). Results: 360 infants were identified. 10/360 (2.8%) had an SBI. All episodes of SBI occurred in infants ≤28 days of age. Two patients had meningitis, two had meningitis with bacteremia, one had isolated bacteremia, and five had UTI. Associated diagnoses included prematurity (46.9%), hyperbilirubinemia (28.3%) and dehydration (14.7%). In multivariable analysis, presentation at 15–28 days (7.60, 1.81–31.86; p = 0.005) compared to 0–14 days, higher absolute neutrophil count (1.25, 1.04–1.50; p = 0.015) and lower platelet count (0.99, 0.99–1.00; p = 0.046) were associated with SBI. Three patients without SBI died during or soon after their hospitalization. One patient had positive testing for herpes simplex. Conclusion: In this cohort of hypothermic infants, 2.8% had a SBI. Age of presentation, ANC, and lower platelet count were associated with serious infections. Hypothermic infants presenting to the ED carry significant morbidity and require prospective study to better risk-stratify this population.