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Acute calcium pyrophosphate arthritis — SCE Acute Medicine MCQ

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HardAcute Rheumatological EmergenciesAcute calcium pyrophosphate arthritisSCE Acute Medicine

An 83-year-old woman taking prednisolone has an acutely hot wrist, temperature 38.2°C and CRP 210 mg/L. Aspirate contains weakly positively birefringent calcium-pyrophosphate crystals; Gram stain is negative. What should happen next?

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Reveal the answer and explanation

Correct answer: D — Culture aspirate, cover sepsis empirically and treat crystal inflammation concurrently

Explanation lettering: C = shown as A · E = shown as B · D = shown as C · A = shown as D · B = shown as E

A is correct. Calcium-pyrophosphate crystals support acute CPP crystal arthritis, but crystals and a negative Gram stain do not exclude concomitant septic arthritis—especially in a febrile immunosuppressed patient with marked inflammation. Send synovial fluid for culture, obtain blood cultures and involve orthopaedic or infection services; antimicrobial treatment follows the clinical probability after sampling. Intra-articular steroid is inappropriate until infection is reasonably excluded. Allopurinol treats urate disease, and outpatient treatment alone disregards systemic features.

Reference: https://ard.bmj.com/content/70/4/571