skip to main content

Septic arthritis — SCE Acute Medicine MCQ

Instant feedback + full explanation. One question, done properly.

ModerateSepsis and Infectious EmergenciesSeptic arthritisSCE Acute Medicine

A 52-year-old man is assessed on the acute medical unit. He has an acutely swollen painful knee, fever and inability to weight bear. He takes prednisolone for polymyalgia rheumatica. Initial assessment includes relevant observations, bedside tests and urgent blood results. What is the most appropriate investigation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Urgent joint aspiration for Gram stain and culture

Urgent joint aspiration for Gram stain and culture is the best answer because joint aspiration before antibiotics where feasible confirms infection and directs therapy. Bedside capillary ketones and venous blood gas is plausible, but it is less appropriate for the physiology or timing described in this stem. The other distractors either fit a neighbouring presentation, delay definitive treatment, or miss the key immediate risk. Clinical pearl: Do not diagnose gout by appearance when septic arthritis is plausible.

Reference: BOA/BSSH septic arthritis guidance