AML and Blood Cell Counts
AML typically presents with elevated white blood cell counts but causes decreased red blood cell counts (anemia), not elevated red blood cells. 1
White Blood Cell Elevation in AML
AML frequently causes marked leukocytosis, with up to 18% of patients presenting with white blood cell counts exceeding 100,000/µL—a condition called hyperleukocytosis. 2
- FLT3-ITD mutations in AML are specifically associated with elevated white blood cell counts and high blast percentages at diagnosis 1
- Hyperleukocytosis (WBC >100,000/µL) occurs in 5-30% of adult AML patients and represents a medical emergency requiring prompt recognition and therapy 3
- Monocytic and myelomonocytic subtypes (M4/M5) are particularly associated with extreme leukocytosis, with 73% of hyperleukocytosis patients having these subtypes 4
- Leukocytosis in AML is associated with inferior overall survival, increased early death, and higher risk of life-threatening complications including leukostasis, disseminated intravascular coagulation, and tumor lysis syndrome 2, 5
Red Blood Cell Status in AML
AML causes anemia (low red blood cells), not elevated red blood cells, due to bone marrow infiltration by leukemic blasts that suppresses normal erythropoiesis. 1
- Anemia results from extensive infiltration of the marrow with leukemia cells 1
- Erythropoietin is of questionable value in AML patients with anemia because the underlying problem is marrow replacement by malignant cells, not erythropoietin deficiency 1
- Transfusions are required to manage anemia in AML patients 1
Critical Management Implications
When WBC counts exceed 100,000/µL in suspected AML, immediate cytoreduction with hydroxycarbamide (50-60 mg/kg/day) should be initiated to prevent leukostasis. 1
- Leukapheresis should be avoided in acute promyelocytic leukemia (APL) as it may exacerbate fatal coagulopathy 1, 6
- In non-APL AML with hyperleukocytosis, leukapheresis does not reduce early mortality and cannot be generally recommended, though if used it should be accompanied by cytoreductive chemotherapy 1