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Iron deficiency anemia

Iron deficiency anemia is a disorder of oxygen transport in which hemoglobin synthesis is deficient. A common disease worldwide, iron deficiency anemia affects 10% to 30% of the adult population of the United States. Iron deficiency anemia occurs most commonly in premenopausal women, infants (particularly premature or low-birth-weight infants), children, and adolescents (especially girls). The prognosis after replacement therapy is favorable.

Causes

Possible causes of iron deficiency anemia are:

Ø inadequate dietary intake of iron (less than 1 to 2 mg/day), as in prolonged nonsupplemented breast-feeding or bottle-feeding of infants or during periods of stress, such as rapid growth, in children and adolescents

Ø iron malabsorption, as in chronic diarrhea, partial or total gastrectomy, and malabsorption syndromes, such as celiac disease and pernicious anemia

Ø blood loss due to drug-induced GI bleeding (from anticoagulants, aspirin, steroids) or heavy menses, hemorrhage from trauma, peptic ulcers, cancer, or varices

Ø pregnancy, which diverts maternal iron to the fetus for erythropoiesis

Ø intravascular hemolysis-induced hemoglobinuria or paroxysmal nocturnal hemoglobinuria

Ø mechanical trauma to RBCs caused by a prosthetic heart valve or vena cava filters.

Pathophysiology

Iron deficiency anemia occurs when the supply of iron is inadequate for optimal formation of RBCs, resulting in smaller (microcytic) cells with less color (hypochromic) on staining. Body stores of iron, including plasma iron, become depleted, and the concentration of serum transferrin, which binds with and transports iron, decreases. Insufficient iron stores lead to a depleted RBC mass with subnormal hemoglobin concentration, and, in turn, subnormal oxygen-carrying capacity of the blood.

Signs and Symptoms

Because iron deficiency anemia progresses gradually, many patients exhibit only symptoms of an underlying condition. They tend not to seek medical treatment until anemia is severe.

At advanced stages, signs and symptoms include:

Ø dyspnea on exertion, fatigue, listlessness, pallor, inability to concentrate, irritability, headache, and a susceptibility to infection due to decreased oxygen-carrying capacity of the blood caused by decreased hemoglobin levels

Ø increased cardiac output and tachycardia due to decreased oxygen perfusion

Ø coarsely ridged, spoon-shaped (koilonchyia), brittle, and thin nails due to decreased capillary circulation

Ø sore, red, and burning tongue due to papillae atrophy

Ø sore, dry skin in the corners of the mouth due to epithelial changes.

Complications

Possible complications include:

Ø infection and pneumonia

Ø pica, compulsive eating of nonfood materials, such as starch or dirt

Ø bleeding

Ø overdosage of oral or IM iron supplements.

Diagnosis

Blood studies (serum iron, total iron-binding capacity, ferritin levels) and iron stores in bone marrow may confirm iron deficiency anemia. However, the results of these tests can be misleading because of complicating factors, such as infection, pneumonia, blood transfusion, or iron supplements. Characteristic blood test results include:

Ø low hemoglobin (males, less than 12 g/dl; females, less than 10 g/dl)

Ø low hematocrit (males, less than 47; females, less than 42)

Ø low serum iron with high binding capacity

Ø low serum ferritin

Ø low RBC count, with microcytic and hypochromic cells (in early stages, RBC count may be normal, except in infants and children)

Ø decreased mean corpuscular hemoglobin in severe anemia

Ø depleted or absent iron stores (by specific staining) and hyperplasia of normal precursor cells (by bone marrow studies).

Ø exclusion of other causes of anemia, such as thalassemia minor, cancer, and chronic inflammatory, hepatic, or renal disease.

Treatment

The first priority of treatment is to determine the underlying cause of anemia. Only then can iron replacement therapy begin. Possible treatments are:

Ø oral preparation of iron (treatment of choice) or a combination of iron and ascorbic acid (enhances iron absorption)

Ø parenteral iron (for patient noncompliant with oral dose, needing more iron than can be given orally, with malabsorption preventing adequate iron absorption, or for a maximum rate of hemoglobin regeneration).

Ø Because total-dose I.V. infusion of supplemental iron is painless and requires fewer injections, it's usually preferred to IM administration. Considerations include:

Ø total-dose infusion of iron dextran (INFeD) in normal saline solution given over 1 to 8 hours (pregnant patients and geriatric patients with severe anemia)

Ø I.V. test dose of 0.5 ml given first (to minimize the risk for an allergic reaction).

Nursing Intervention

• —Monitor VS
• —Weight pt daily
• —Monitor other S/Sx of anemia
• —Stop activity if RR and PR increase-People with anemia experience easy Fatigueability that is why it is one of the priorities in managing anemia.
  
• —Teach pt to move slowly when changing position —Allow periods of rest between activities
• —Administer iron supplements as prescribed
• —Do not give oral iron supplements with milk and antacids
• —Give iron w/ orange juice because Vit C increases absorption
• —Give iron IM on Z-tract method
• —Give iron IV on slow push to prevent vein irritation—
• Give Elixir by straw to prevent staining of the teeth
• —Increase fluid intake and fruits and vegetables to prevent constipation
• —Teach pt that iron supplements causes stools to be dark
• —Teach pt signs of toxicity: nausea and vomiting, abdominal cramping, fever,diarrhea

Sources: Brunner and Suddarth's textbook of Medical-Surgical Nursing, Frizzell- handbook of pathophysiology, Saunder's Manual of Nursing Care, Lippincott's Critical Care Challenges