PATHOPHYSiology of iron deficiency anemia

Answer 1

Iron deficiency develops in several stages. In the first stage, body iron requirement exceeds iron intake, causing progressive depletion of bone marrow iron stores. As iron reservoirs decrease, compensatory increases in absorption of dietary iron occur. During later stages, deficiency is severe enough to impair red blood cell biosynthesis, leading to anemia. Iron deficiency, if severe and prolonged, may cause dysfunction of iron-containing cellular enzymes, which may contribute to fatigue and loss of stamina via mechanisms independent of the anemia itself. Iron deficiency anemia must be differentiated from other types of microcytic anemia, such as anemia caused by deficient erythropoiesis or decreased red blood cell production due to other underlying causes. If tests exclude iron deficiency in a patient with microcytic anemia, then anemia of chronic disease, structural hemoglobin abnormalities (e.g., hemoglobinopathies), and congenital red blood cell membrane abnormalities are considered. Clinical laboratory studies of hemoglobin electrophoresis and HbA 2, as well as genetic testing (e.g., alpha-thalassemia), may help distinguish these entities.