The prevalence for the risk of serious infection in hypothermic infants ≤ 60 days: A systematic review

Background Temperature abnormalities in infants may be a sign of a serious infection (SI) and there is literature regarding the workup of the febrile infant to help guide management. The prevalence of SIs in hypothermic infants and the development of established guidelines for this population has not been established. Our primary objective was to determine the prevalence of SI in hypothermic infants who are 60 days old or younger presenting to the emergency department (ED). In addition, we calculated the prevalence of SI by organ system and identified its microorganism. Methods We performed a systematic review by searching the literature in Medline, Embase, Web of Science, and CINAHL. We limited our search to infants <= 60 days with a rectal temperature <36.5 degrees C who presented to the ED. We defined SI as bacteremia, urinary tract infection (UTI), meningitis, herpes simplex virus infections, or pneumonia. We calculated the prevalence of SI. Quality of studies and bias was assessed using QUADAS-2. Our study was registered with PROSPERO, 2020 CRD42020153477. Results We identified 1242 articles from our initial search in December 2019 followed by a second search in February 2021 to capture any recent publications. We identified four studies meeting our inclusion criteria. We estimated the prevalence of SI as 4.86% (95% confidence Interval [CI] 1.97-8.82) for infants <= 60 days old. In a subgroup analysis of infants <= 28 days (n = 16/374), we estimated the prevalence of SI as 5.15 (95% CI 0.95-12.0). The most common source for SI was UTI, with a prevalence of 2.16% (95% CI 1.18-3.60). Conclusion The overall prevalence of SI was 4.86% in hypothermic young infants <= 60 days old presenting to the ED. Infants <= 28 days had a slightly higher prevalence of 5.15%. The most common source for serious bacterial infection was UTI.