A 32-year-old man presents with gum bleeding, epistaxis, and ecchymoses. CBC: hemoglobin 9.0 g/dL, WBC 26,000/uL, platelets 18,000/uL. PT is prolonged, fibrinogen 85 mg/dL, D-dimer markedly elevated. Bone marrow is packed with abnormal promyelocytes containing multiple Auer rods. What is the immediate priority in management?
- A Start all-trans retinoic acid immediately, before awaiting complete confirmatory testing ✓
- B Start imatinib and defer chemotherapy until cytogenetics return
- C Give hydroxyurea to lower the leukocyte count and reassess coagulation profile
- D Transfuse platelets and plasma only, and begin induction chemotherapy after 48 hours
Correct answer: A. Start all-trans retinoic acid immediately, before awaiting complete confirmatory testing
Explanation
The combination of promyelocytes, multiple Auer rods, and DIC (low fibrinogen, high D-dimer, prolonged PT) defines acute promyelocytic leukaemia, driven by the PML-RARA fusion of t(15;17), which blocks myeloid maturation at the promyelocyte stage. All-trans retinoic acid binds RARA and releases this block, rapidly correcting the coagulopathy, so it must start at once, with arsenic trioxide added in current regimens. Imatinib targets BCR-ABL, which is irrelevant here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.