Background: Children with acute arthritis are commonly admitted to the hospital in part due to concern for septic arthritis (SA) and its complications. Many non-infectious, non-urgent conditions are more common than SA and present similarly. The epidemiology and clinical presentation of SA influences management of patients with acute arthritis.
Methods: Utilizing the electronic medical record, we reviewed the charts of children (1-18 years old) with joint complaints who presented to the hospitals and clinics of one large academic health organization in the Upper Midwest from Jan 2011 to July 2016. Query criteria included the presenting symptom (arthritis, joint swelling, or joint pain), diagnosis (arthritis, septic arthritis, or Lyme arthritis), and/or positive synovial fluid culture. SA was confirmed when synovial bacterial culture or PCR were positive. SA was suspected in cases with a positive blood culture or when the patient was treated empirically with 4 weeks of antibiotic with no alternate diagnosis. All other children were excluded from the study cohort.
Results: Of the 705 children whose charts were reviewed, 609 were excluded with a non-infectious diagnosis and 72 with Lyme arthritis (figure 1). We identified 24 children with SA. 6 children diagnosed with SA were immunosuppressed. Among healthy children with SA, 7 were diagnosed with contiguous musculoskeletal (MSK) infection and 11 were diagnosed with acute, isolated, monoarticular arthritis. SA was more common in boys. The most common pathogen isolated was S aureus(13). The knee (7) and hip (6) accounted for the majority of joints involved in healthy children.
Conclusion: SA is a rare cause of acute arthritis in children. In healthy children, SA may present with contiguous MSK infection or in an isolated joint. SA is more likely in boys and in the knee or hip joint. S aureus is the most common cause of SA. Clear understanding of the epidemiology and clinical history of SA should shape clinical decision making in children with acute arthritis.
MSK musculoskeletal, SA septic arthritis, OM osteomyelitis, DVT deep venous thrombosis, Cx- culture negative