Fever, Leg Pain, Pediatrics – Blood Culture or Not?

May 16, 2023

Written by Christian Gerhart

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Bacteremia is common in pediatric patients who present to the ED with fever and acute lower extremity pain. Obtain a blood cultures in these patients, as it is likely to assist in diagnosis or change management, particularly if they also have a higher fever, focal bony tenderness, or an elevated CRP. 

Why does this matter?
Fever and acute lower extremity pain is a common pediatric presentation. The presence of bacteremia can change management, but blood cultures in the ED also come with the daunting prospect of drawing additional blood from children and the non-trivial risk of contamination, which can lead to harm from unnecessary treatments.  

To culture or not to culture?
This was a cross-sectional, retrospective study of 689 patients at a single tertiary care pediatric ED using a natural language processing-assisted manual chart review. They included immunocompetent children with normal baseline bone health, aged 1-18 who presented to the ED with fever and acute, atraumatic lower extremity pain. The prevalence of bacteremia in patients who had blood cultures drawn was high at 13.7% (95%CI 10.9 to 17.0%). Culprit organisms were MSSA (71.6%), MRSA (15.7%), S. pyogenes (11.5%) and Salmonella spp. (1.4%). The rate of blood culture contamination in this cohort was low at 1.6%. 17/70 (24.3%) of patients with a positive blood culture had a change in management, such as callback to the ED or a change in antibiotic regimen. CRP>3 (OR 4.5, 95%CI 2.1-9.6), fever height (OR 3.8, 95%CI 2.3.6.2) and localizing exam findings (OR 3.3, 95%CI 1.4-7.9) were the patient factors most likely to be associated with bacteremia.

Source
Bacteremia in Children With Fever and Acute Lower Extremity Pain. Pediatrics. 2023 Apr 4;e2022059504. doi: 10.1542/peds.2022-059504. Online ahead of print.