An 8-year-old boy present...

An 8-year-old boy presented with complaints of pain, swelling, and difficulty moving the left knee for four weeks. The pain was insidious in onset, initially mild, and gradually progressed over time. He also complained of fever and swelling. He had mild diarrhoea 4–5 weeks prior, which subsided with symptomatic medication. There was no history of antecedent trauma or cough, breathlessness, hemoptysis, weight loss, or night sweats. The patient was locally treated with cefixime, but it did not improve. On examination, tenderness and swelling of the left knee, with restriction of movement, were observed. Systemic examination was unremarkable. Cultures of the synovial fluid and tissue confirmed the presence of Salmonella enterica (S. enterica). High-resolution ultrasonography (USG) of the left knee joint was performed for further analysis