Hyperpyrexia and high fever as a predictor for serious bacterial infection (SBI) in children—a systematic review

It is not clear if children with high fever are at increased risk for serious bacterial infection (SBI). Our aim was to systematically review if children suffering from high fever are at high risk for SBI. Our data sources were Embase, Medline, and Pubmed; from their inception until the last week of March 2017. The study selection were of cohort and case control studies comparing the incidence of SBI in children with hyperpyrexia with children with fever of 41 °C or less, and children with a temperature higher than 40 °C, with children with fever of 40 °C or less. Two reviewers independently pooled studies for detailed review using a structured data-collection form. We calculated the odds ratio and 95% confidence intervals (CI) for SBI, assuming a random-effects model. A sub-group analysis was conducted. In our results, 11 studies met the inclusion criteria. Two studies showed that children with hyperpyrexia are at higher risk for SBI (OR 1.96 95% CI 1.3–1.97). An increased risk for SBI in children with high fever (OR 3.21 95% CI 1.67; 6.22). SBI in infants with temperature over 40 °C was higher compared to infants with lower degree of fever (OR 6.3 95% CI 4.44; 8.95). On older children, the risk for SBI was only slightly higher in children with fever above 40 °C. The limitation of the study is the small amount of studies and that the heterogeneity of the studies was very high. Conclusion: Young infants with temperature higher than 400 °C are at increased risk for SBI. Risk of SBI in older children with temperature > 400C is minimal.What is known:• An association between high fever and increased risk for SBI was reported in young infants.• Based on only two studies from the 1970s and 1980s, hyperpyrexia is associated with increased risk for SBI.What is new:• Infants under the age of 3 months with fever > 40 °C were found to have increased risk for SBI.• Risk of SBI in older children with temperature > 40 °C is minimal.