hematology and oncology
Megaloblastic Macrocytic Anemias
Etiology of Megaloblastic Macrocytic Anemias
Themost common causesof megaloblastic states are Vitamin B12 Deficiency None Defective utilization of vitamin B12 Folate Deficiency None The most common cause of B12 deficiency is pernicious anemia due to impaired intrinsic factor secretion (usually secondary to the presence of autoantibodies—see Autoimmune Metaplastic Atrophic Gastritis ). Pernicious anemia can develop even in the absence of old age. Other common causes are malabsorption due to . However, folate deficiency can occur in patients with restrictive diets, chronic alcohol use, or anorexia. Malabsorptive conditions such as Celiac Disease , , or immunosuppressants) that interfere with DNA synthesis and rare metabolic disorders (eg, hereditary orotic aciduria). Copper Deficiency can cause megaloblastic changes in some cases and may manifest as macrocytic, normocytic, or even microcytic anemia. 