Anemia, iron deficiency
Description
Decreased total iron body content, leading to diminished erythropoiesis
Produces smaller (microcytic) cells with less color on staining (hypochromia)
Most common form of anemia
Pathophysiology
Body stores of iron, including plasma iron, decrease.
Transferrin, which binds with and transports iron, increases.
Insufficient body stores of iron leads to a depleted red blood cell (RBC) mass and to a decreased hemoglobin (Hb) concentration.
Oxygen-carrying capacity of the blood is, ultimately, decreased. (See Iron absorption and storage, page 10.)
Causes
Blood loss secondary to drug-induced GI bleeding or due to heavy menses or hemorrhage from trauma, GI ulcers, or malignant tumors
Can be related to lead poisoning
Inadequate dietary intake of iron
Intravascular hemolysis-induced hemoglobinuria or paroxysmal nocturnal hemoglobinuria
Iron malabsorption
Iron absorption and storage
Found in abundance throughout the body, iron is needed for erythropoiesis. Two-thirds of total-body iron is found in hemoglobin (Hb); the other third, mostly in the reticuloendothelial system (liver, spleen, and bone marrow), with small amounts in muscle, serum, and body cells.
Adequate iron in the diet and recirculation of iron released from disintegrating red blood cells maintain iron supplies. The duodenum and upper part of the small intestine absorb dietary iron. Such absorption depends on gastric acid content, the amount of reducing substances (ascorbic acid, for example) present in the alimentary canal, and amount of iron intake. If iron intake is deficient, the body gradually depletes its iron stores, causing decreased Hb levels and, eventually, signs and symptoms of iron deficiency anemia.