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Septic Arthritis — SCE Rheumatology MCQ

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ModerateRheumatology EmergenciesSeptic ArthritisSCE Rheumatology

A 48-year-old woman with RA develops a severely swollen painful left knee while on Adalimumab. Joint aspiration reveals purulent fluid with WCC 65000/microL (95% neutrophils). Gram stain shows Gram-positive cocci in clusters. What is the most critical action?

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Correct answer: A — Stop Adalimumab and start IV Flucloxacillin with orthopaedic washout

Septic arthritis in a patient on biologic therapy is a medical emergency. Gram-positive cocci in clusters indicate Staphylococcus aureus, the commonest organism. IV Flucloxacillin (or Vancomycin if MRSA suspected) should be started immediately. Adalimumab must be stopped to allow immune reconstitution. Orthopaedic referral for joint washout (arthroscopic or open) is essential. BSR biologic safety guidelines identify serious infection as a key risk with all biologics. The biologic should not be restarted until infection is fully treated and resolved.

Reference: BSR 2006 hot swollen joint guidelines; BSR 2019 biologic safety guidelines