Iron Deficiency Anemia
A common disease worldwide, iron deficiency anemia affects 10% to 30% of the adult population of North America. It’s most prevalent among premenopausal females, infants (particularly premature or low–birth weight infants), children, adolescents (especially females), alcoholics, and elderly people (especially those unable to cook). The prognosis after replacement therapy is favorable.
Causes
Iron deficiency anemia stems from an inadequate supply of iron for optimal formation of red blood cells (RBCs), which produces smaller (microcytic) cells with less color on staining. Body stores of iron, including plasma iron, decrease, as does transferrin, which binds with and transports iron. Insufficient body stores of iron
lead to a depleted RBC mass and, in turn, to a decreased hemoglobin (Hb) concentration (hypochromia) and decreased oxygen-carrying capacity of the blood. (See Understanding iron absorption and storage.)
lead to a depleted RBC mass and, in turn, to a decreased hemoglobin (Hb) concentration (hypochromia) and decreased oxygen-carrying capacity of the blood. (See Understanding iron absorption and storage.)
Understanding iron absorption and storage
Essential to erythropoiesis, iron is abundant throughout the body. 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 dietary ingestion of iron and recirculation of iron released from disintegrating red 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 dietary iron intake. If iron intake is deficient, the body gradually depletes its iron stores, causing decreased Hb and, eventually, signs and symptoms of iron deficiency anemia.
Iron deficiency can result from any of the following:
inadequate dietary intake of iron, as in prolonged unsupplemented breast-or bottle-feeding of infants, during periods of stress such as rapid growth in children and adolescents, and in elderly patients existing on a poorly balanced diet
iron malabsorption, as in chronic diarrhea, partial or total gastrectomy, and malabsorption syndromes such as celiac disease
blood loss secondary to drug-induced GI bleeding (from anticoagulants, aspirin, or steroids) or due to heavy menses, hemorrhage from trauma, GI ulcers, malignant tumors, and varices
pregnancy, in which the mother’s iron supply is diverted to the fetus for erythropoiesis
intravascular hemolysis-induced hemoglobinuria or paroxysmal nocturnal hemoglobinuria
mechanical erythrocyte trauma caused by a prosthetic heart valve or vena cava filter.
Complications
Potential complications of this disorder include infection and pneumonia. Lead poisoning may result from increased intestinal absorption of lead when combined with pica, another symptom of this disorder. Another complication is bleeding, which may be identified by ecchymotic areas on the skin, hematuria, and gingival bleeding. Plummer-Vinson syndrome can occur in severe cases.
The most significant complication of iron deficiency anemia stems from overreplacement of iron with oral or I.M. supplements. Hemochromatosis (excessive iron deposits in tissue) can result, affecting the liver, heart, pituitary gland, and joints.
Pediatric pointerIron poisoning can occur in children when toxic levels are allowed to build up during therapy.
Assessment
Iron deficiency anemia may persist for years without signs and symptoms. The characteristic history of fatigue, inability to concentrate, headache, and shortness of breath (especially on exertion) may not develop until long after iron stores and circulating iron become low. The patient may report increased frequency of infections and pica, an uncontrollable urge to eat strange things, such as clay, starch, ice and, in children, lead. A female patient may give a history of menorrhagia.
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