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Iron Deficiency Anemia

Iron deficiency is the most common cause of anemia in many parts of the world and is usually the result of blood loss, often combined with inadequate dietary iron. Iron deficiency occurs most commonly in menstruating women. When iron requirements or the loss of iron exceed the quantity of iron absorbed, the individual experiences a state of negative iron balance. With this negative balance, iron stores decrease progressively and synthesis of hemoglobin is impaired after storage iron is exhausted.

Causes of iron deficiency

Inadequate dietary iron for high physiologic requirements. Iron deficiency is the most common nutritional deficiency in the world. Infants, adolescents and women of child bearing age are at the highest risk of iron deficiency and may become iron deficient because of inadequate dietary iron to meet physiologic needs. Infants one to two years of age and adolescents have.

Blood loss. Other than in children and women of child bearing age, the finding of iron deficiency almost always signifies pathological blood loss of some sort. Populations with hookworm infestation have an increased incidence of iron deficiency due to chronic intestinal blood loss.

Malabsorption, hemoglobinuria, pulmonary hemosiderosis. Iron deficiency also may in patients with defective absorption of food iron due to tropical sprue and other tropical enteropathies, achlorhydria and gastric resection.

Clinical features of iron deficiency. These include fatigue, irritability, headaches, paresthesias, glossitis (a smooth red tongue), angular cheilitis, pallor, and koilonychia (spooning of the nails). Pica, the craving to eat unusual substances such as ice, clay or dirt.

Symptoms. Even in the absence of anemia, iron deficiency may have adverse effects. Non-anemic children with prolonged iron deficiency in the second year of life were later found to have impaired mental and motor development at five years of age. In pregnancy, maternal iron deficiency may be associated with low fetal birth weight and increased prematurity. In adults with iron deficiency, reduced capacity for strenuous work and exercise has been reported.

C. Management of iron deficiency

1. Identify the cause. Iron deficiency as the cause of anemia is suspected on epidemiologic grounds. As discussed above, the condition is a common cause of low hemoglobin in infants, adolescents, women of childbearing age, individuals with hookworm infestation.

2. Oral iron therapy. Iron deficiency anemia is almost always treated with oral iron preparations. The typical adult dose is 200 mg of elemental iron per day, for example one 300 mg ferrous sulfate tablet three times a day (300 mg ferrous sulfate = 65 mg elemental iron). The pediatric dose is 5 mg/kg of elemental iron per day in tablet or elixir form.

Carbonyl iron is an elemental iron powder that may be given in capsule form and has similar efficacy to iron salts in correcting iron deficiency. Elemental iron has the advantage of having remarkably reduced toxicity when compared to iron salts.

The treatment of iron deficiency anemia is oral iron replacement. The most commonly used agent, ferrous sulfate, is inexpensive and well absorbed. Most patients respond to oral iron therapy if they are compliant, and intramuscular or intravenous iron dextran is rarely necessary. 

3. Parenteral iron. Parenteral iron in the form of iron-dextran may be given intramuscularly or intravenously, but does not lead to a more rapid hematologic response than oral iron.

4. Blood transfusion. Blood transfusion should be avoided if at all possible, but may be necessary for individuals with anemia so severe as to cause cardiorespiratory embarrassment.

D. Prevention of iron deficiency. Iron deficiency is such a prevalent problem that it is appropriate to approach prevention on a population basis.