A 40-year-old man with acute promyelocytic leukaemia started on all-trans retinoic acid and idarubicin develops fever, dyspnoea, hypoxia with bilateral pulmonary infiltrates, and 4 kg weight gain on day 12 of therapy. Repeat peripheral smear shows maturing myeloid precursors with no blasts. What is the best next step?
- A Discontinue all-trans retinoic acid permanently
- B Intravenous dexamethasone ✓
- C Broad-spectrum empirical antibiotics alone
- D Platelet transfusion and close observation
Correct answer: B. Intravenous dexamethasone
Explanation
Fever, hypoxia, pulmonary infiltrates and rapid weight gain in a patient receiving ATRA define differentiation syndrome, driven by cytokine release from maturing promyelocytes. First-line treatment is intravenous dexamethasone, with temporary ATRA interruption if severe. Antibiotics alone fail because the pulmonary process is sterile inflammatory infiltration rather than infection, although superimposed infection must be considered. Permanent discontinuation of ATRA compromises cure.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.