Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a clonal malignancy of myeloid precursor cells. The abnormal blasts proliferate without normal differentiation and crowd out healthy hematopoiesis. Reduced erythrocyte production causes anemia; reduced platelet production causes thrombocytopenia and bleeding; and reduced functional neutrophil production increases infection risk. The total white-cell count may be low, normal, or high, and a high count does not prove that the circulating cells can defend against infection. This mechanism explains the bedside pattern. Anemia can cause fatigue, pallor, dizziness, reduced exercise tolerance, palpitations, and dyspnea. Thrombocytopenia can cause petechiae, bruising, gingival bleeding, epistaxis, hematuria, gastrointestinal bleeding, or oozing from puncture sites. Neutropenia or dysfunctional leukocytes can allow infection to become severe with few local inflammatory signs. A large circulating blast burden can also impair microvascular perfusion. Hyperleukocytosis is typically defined as a white-cell count greater than 100 × 10⁹/L, but leukostasis can occur below that value and is a clinical emergency rather than a diagnosis made from the count alone. Respiratory distress, hypoxemia, headache, confusion, visual change, or a focal neurologic deficit in this setting suggests end-organ injury....