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Septic arthritis — MRCPCH FOP MCQ

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HardInfectious diseasesSeptic arthritisMRCPCH FOP

A 4-year-old boy refuses to bear weight on his right leg. He is febrile, the right hip is held flexed and externally rotated, CRP is markedly raised and passive movement is very painful. What is the most likely diagnosis?

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Correct answer: B — Septic arthritis of the hip

Fever, raised inflammatory markers, inability to bear weight and severe pain on passive hip movement suggest septic arthritis. Transient synovitis is usually less systemically unwell and often follows a viral illness with lower inflammatory markers. Growing pains do not cause fever or refusal to bear weight. The pearl is that septic arthritis of the hip is an orthopaedic emergency.

Reference: BOA/BSCOS paediatric septic arthritis standards; NICE CKS Limp in children