Bacteremia in Children With Fever and Acute Lower Extremity Pain.

Background And Objectives: Blood cultures (BCxs) are often obtained in the initial evaluation of children with fever and acute lower extremity pain; however, their yield in this population is unknown. We aim to describe the prevalence of bacteremia among children presenting to the emergency department (ED) with fever and acute lower extremity pain and identify predictors of bacteremia.

Methods: Cross-sectional review of children aged 1 to 18 years presenting to the ED with fever and acute lower extremity pain between 2010 and 2020. We excluded patients with trauma within the previous 24 hours, orthopedic comorbidity, immunocompromised status, or antibiotic pretreatment. We identified our cohort using a Natural Language Processing-assisted model with manual review and abstracted clinical data. Our primary outcome was a BCx positive for a pathogen.

Results: We screened 478 979 ED notes and identified 689 patients who met inclusion criteria. Median age was 5.3 years (interquartile range 2.7-8.8); 39.5% were female. BCxs were obtained from 75.9% (523/689) of patients, of which 510 were available for review. BCxs were positive in 70/510 (13.7%; 95% CI, confidence interval [CI], 10.9-17.0) of children and in 70/689 (10.2%; 95% CI, 8.0-12.7%) of the entire cohort. The most common pathogens were methicillin-susceptible Staphylococcus aureus (71.6%) and methicillin-resistant Staphylococcus aureus (15.7%). Predictors of bacteremia include C-reactive protein ≥3 mg/dL (odds ratio, 4.5; 95% CI, 2.1-9.6) and localizing examination findings (odds ratio, 3.3; 95% CI, 1.4-7.9).

Conclusions: The prevalence of bacteremia among children presenting to the ED with fever and acute lower extremity pain is high. Routine BCx should be considered in the initial evaluation of this population.