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Differentiation Syndrome — RACP Adult Medicine MCQ

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HardHaematologyDifferentiation SyndromeRACP Adult Medicine

A 65-year-old man with newly diagnosed AML undergoes induction chemotherapy with cytarabine and daunorubicin (7+3 regimen). On day 10, he develops sudden onset dyspnoea, rapidly rising WCC, and bilateral pulmonary infiltrates. Chest X-ray shows diffuse bilateral opacities. What is the most likely complication?

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Correct answer: D — Differentiation syndrome

Differentiation syndrome (previously retinoic acid syndrome) occurs in AML patients during induction – most classically with ATRA for APL but can occur with other agents. Features include fever, dyspnoea, pulmonary infiltrates, weight gain, oedema, and rising WCC. However, in standard AML induction (7+3), this presentation is more likely leukostasis or infection. If ATRA or IDH inhibitors are being used, differentiation syndrome is the key concern. Treatment is dexamethasone 10 mg IV BD.

Reference: eTG – 2025 – Haematology