septic arthritis in an immunocompetent child: A case report.

A 2-year-old, previously healthy, male presented with an insidious history of intermittent left knee pain and edema who had been evaluated in the emergency department on multiple occasions with unremarkable imaging and normal laboratory results. On the day of presentation, he had mild edema of the left knee and inability to bear weight. Synovial fluid analysis showed an elevated white cell count with neutrophil predominance and mildly elevated inflammatory markers, consistent with septic arthritis.