Pediatric Musculoskeletal Infections

Bacterial musculoskeletal infections (MSKIs), including septic arthritis, osteomyelitis, and pyomyositis, are challenging diagnoses to make in pediatric emergency medicine because their presentation frequently overlaps with more common conditions, including transient synovitis, Lyme arthritis, reactive arthritis, and other inflammatory arthritides. While delayed diagnosis may result in significant morbidity, over-testing may expose children to invasive procedures, advanced imaging, sedation, hospitalization, and unnecessary antimicrobial therapy. Pediatric emergency clinicians must therefore balance the competing risks of missed infection and excessive diagnostic evaluation and treatment. Numerous tools exist to aid clinicians, including blood biomarkers-white blood cell (WBC) count, absolute neutrophil count (ANC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and procalcitonin (PCT). However, blood biomarkers have limited diagnostic accuracy when used in isolation. To address this limitation, clinical prediction tools that combine laboratory values with clinical features to stratify risk have been developed. In this review, we summarize the data for clinically available biomarkers and clinical prediction tools for the evaluation of pediatric bacterial MSKIs and discuss their practical application, limitations, and integration into clinical decision-making in the emergency department (ED). Ultimately, we provide a framework to help pediatric emergency clinicians identify children who require advanced testing and interventions while avoiding unnecessary evaluation and treatment in low-risk patients.