Adult-Onset Still Disease — RACP Adult Medicine MCQ

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HardRheumatologyAdult-Onset Still DiseaseRACP Adult Medicine

A 30-year-old woman presents with FUO, evanescent salmon-pink rash (quotidian pattern), arthralgia, sore throat, and markedly elevated serum ferritin (15000 μg/L) with glycosylated ferritin fraction <20%. WCC 22 × 10⁹/L (neutrophilia). ANA and RF are negative. Blood cultures are negative. What is the most likely cause of FUO?

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Correct answer: C — Adult-onset Still disease

Quotidian fever (daily spike with return to normal), evanescent salmon-pink rash, arthralgia, sore throat, leucocytosis, and markedly elevated ferritin (>10000) with glycosylated fraction <20% (highly specific) in a young adult is adult-onset Still disease. Yamaguchi criteria are used for diagnosis (exclusion of infection, malignancy, and autoimmune disease). Treatment: NSAIDs for mild, corticosteroids for moderate, and anakinra/tocilizumab for severe/refractory AOSD.

Reference: eTG Rheumatology – 2024 – AOSD; Yamaguchi Criteria