Megaloblastic Anemias: Nutritional and Other Causes

Vitamin B and folate deficiencies are major causes of megaloblastic anemia. Causes of B deficiency include pernicious anemia, gastric surgery, intestinal disorders, dietary deficiency, and inherited disorders of B transport or absorption. The prevalence of folate deficiency has decreased because of folate fortification, but deficiency still occurs from malabsorption and increased demand. Other causes include drugs and inborn metabolic errors. Clinical features of megaloblastic anemia include anemia, cytopenias, jaundice, and megaloblastic marrow morphology. Neurologic symptoms occur in B deficiency, but not in folate deficiency. Management includes identifying any deficiency, establishing its cause, and replenishing B or folate parenterally or orally.