From the Guidelines
Anemia in acute leukemia is primarily caused by bone marrow infiltration by leukemic cells, which disrupts normal hematopoiesis, as well as other factors such as bleeding complications, increased red cell destruction, nutritional deficiencies, and the toxic effects of chemotherapy. The causes of anemia in acute leukemia can be multifactorial, including:
- Bone marrow infiltration by leukemic cells, leading to decreased erythrocyte production 1
- Bleeding complications from associated thrombocytopenia
- Increased red cell destruction (hemolysis)
- Nutritional deficiencies, such as iron, folate, or vitamin B12 deficiency 1
- Toxic effects of chemotherapy on normal bone marrow precursors during treatment
- Inflammatory cytokines released during the disease process, which can impair iron utilization and erythropoietin production, further contributing to anemia 1 The anemia is typically normocytic and normochromic, reflecting the underlying bone marrow failure rather than specific nutritional deficiencies. Management involves treating the underlying leukemia with appropriate chemotherapy regimens, while providing supportive care with red blood cell transfusions to maintain adequate hemoglobin levels, typically aiming for hemoglobin above 7-8 g/dL or higher in symptomatic patients. It is essential to consider other correctable causes of anemia before initiating therapy with stimulants of erythropoiesis, and to conduct an appropriate history and physical, and consider relevant diagnostic testing aimed at identifying causes of anemia aside from chemotherapy or underlying hematopoietic malignancy 1. A comprehensive evaluation of anemia often uses both morphologic and kinetic approaches, including characterization of anemia based on the mean corpuscular volume (MCV) and reticulocyte count 1. Any cause of anemia that may be rectified independent of cancer therapy should be treated as indicated.
From the Research
Causes of Anemia in Acute Leukemia
- Anemia in acute leukemia can be caused by various factors, including:
- Micronutrient deficiencies, such as folate and vitamin B12 deficiency, as seen in patients with acute lymphoblastic leukemia (ALL) 2
- Leukemia cell infiltration, which can cause defective erythropoiesis, as demonstrated in a murine model of acute myeloid leukemia (AML) 3
- Hyperleukocytosis, which can lead to leukostasis and disseminated intravascular coagulation (DIC), resulting in anemia 4
- Cancer-related anemia, which is characterized by a hyporegenerative, normocytic, normochromic anemia associated with reduced serum iron and transferrin saturation but elevated (or normal) ferritin levels 5
- The pathophysiology of anemia in acute leukemia can be classified into three broad categories:
- Decreased/defective red blood cell production
- Increased loss/destruction of red blood cells
- A mixture of both mechanisms operating simultaneously 6
- Specific mechanisms underlying anemia in acute leukemia include:
- Impaired iron utilization
- Suppression of erythroid progenitor cells differentiation
- Inadequate erythropoietin production
- Shortened life span of red blood cells 5