Anemia: Production Defects Generally Associated with Marrow Erythroid Hyperplasia and Ineffective Erythropoiesis

This review focuses on anemia resulting from production defects generally associated with marrow erythroid hyperplasia and ineffective erythropoiesis. The definition, epidemiology, etiology, pathogenesis, diagnosis, differential diagnosis, management, complications, and prognosis of the following production defects are discussed: Megaloblastic anemias, megaloblastic anemia caused by cobalamin deficiency, megaloblastic anemia caused by folic acid deficiency, copper deficiency, and sideroblastic anemias. Figures depict intracellular interdependent cofactor activity of cobalamin and folic acid, synthesis of succinyl–coenzyme A from methylmalonyl–coenzyme A, folic acid functions as a coenzyme in single-carbon transfer reactions, cobalamin assimilation, peripheral blood smear in folic acid or cobalamin deficiency, and a Prussian blue stain showing ring sideroblasts. Tables list causes of cobalamin deficiency and folic acid deficiency. This review contains 5 figures; 2 tables; 95 references.