Macrocytic anemia

An anemia characterized by an increased mean corpuscular volume (MCV >100 fL) with reduced hemoglobin and/or hematocrit, caused by impaired erythropoiesis resulting in enlarged erythrocytes.

Causes

• Nutritional deficiencies

  • Vitamin B12 deficiency

  • Folate deficiency

  • Malabsorption disorders causing impaired vitamin absorption

  • Pernicious anemia

  • Dietary deficiency or malnutrition

• Alcohol-induced bone marrow suppression

• Liver disease

• Medications interfering with DNA synthesis

  • Chemotherapy agents

  • Antiseizure medications

  • HIV antiretroviral therapy

  • Methotrexate

• Hypothyroidism

• Myelodysplastic syndrome causing bone marrow failure

• Reticulocytosis due to increased red blood cell turnover

• Hemolytic anemia with increased reticulocyte production

• Chronic systemic illness

• Pregnancy

• Genetic disorders affecting red blood cell maturation