2 learning resources available for this topic
Acute leukemia — encompassing acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) — is an aggressive hematologic malignancy characterized by rapid proliferation of immature blast cells that crowd out normal hematopoiesis. It constitutes a medical emergency due to risks of infection, hemorrhage, and metabolic derangements.
Leukemic blasts arise from acquired genetic mutations in hematopoietic progenitor cells, leading to a block in differentiation and uncontrolled proliferation. In AML, specific cytogenetic abnormalities (e.g., t(15;17) in APL, t(8;21)) carry prognostic significance. In ALL, Philadelphia chromosome (t(9;22)) is the most important adverse prognostic marker. Bone marrow infiltration results in anemia, thrombocytopenia, and neutropenia.
Clinical reasoning centers on recognizing the constellation of bone marrow failure: fatigue and pallor (anemia), bleeding and petechiae (thrombocytopenia), and recurrent infections (neutropenia). Peripheral blood smear may show blasts. Diagnosis requires bone marrow biopsy with ≥20% blasts. Differentials include aplastic anemia, myelodysplastic syndrome, and viral bone marrow suppression. APL is a hematologic emergency — immediate ATRA therapy is initiated on clinical suspicion before cytogenetics confirm.