Chapter 45 Iron Deficiency Anemia
PATHOPHYSIOLOGY
Iron deficiency anemia is the most common anemia affecting children in North America. The full-term infant born of a well-nourished, nonanemic mother has sufficient iron stores until the birth weight is doubled, generally at 4 to 6 months. Iron deficiency anemia is generally not evident until 9 months of age. After that, iron must be available from the diet to meet the child’s nutritional needs. If dietary iron intake is insufficient, iron deficiency anemia results. Most often, insufficient dietary iron intake results from inappropriately early introduction of solid foods (before age 4 to 6 months), discontinuation of iron-fortified infant formula or breast milk before age 1 year, and excessive consumption of cow’s milk to the exclusion of iron-rich solids in the toddler. Also, the preterm infant, the infant with significant perinatal blood loss, and the infant born to a poorly nourished, iron-deficient mother may have inadequate iron stores. Such an infant would be at a significantly higher risk for iron deficiency anemia before age 6 months. Maternal iron deficiency may cause low birth weight and preterm delivery.
Iron deficiency anemia may also result from chronic blood loss. In the infant, this may be due to chronic intestinal bleeding caused by the heat-labile protein in cow’s milk. In children of all ages, the loss of as little as 1 to 7 ml of blood daily through the gastrointestinal tract may lead to iron deficiency anemia. Other causes of iron deficiency anemia include nutritional deficiencies such as folate (vitamin B12) deficiency, sickle cell anemia, thalassemia major, infections, and chronic inflammation. In teenaged girls, iron deficiency anemia may also be due to excessive menstrual flow.
INCIDENCE
1. Of infants 12 to 36 months of age, 3% have iron deficiency anemia.
2. Of infants 12 to 36 months of age, 9% are iron deficient.
3. Incidence of iron deficiency and iron deficiency anemia among adolescent girls is 11% to 17%.
4. The age range of peak incidence for iron deficiency anemia is 12 to 18 months.
5. Prevalence rates of iron deficiency are higher among children living at or below the poverty level and among African-American and Mexican-American children.
6. Of infants fed only non–iron-fortified formula or cow’s milk, 20% to 40% are at higher risk for iron deficiency by age 9 to 12 months.
7. Of breast-fed infants, 15% to 25% are at higher risk for iron deficiency by age 9 to 12 months.
8. The leading cause of anemia in infants and children in the United States is iron deficiency. There was a significant increase in iron deficiency anemia in the United States in the 1990s.
9. Iron deficiency is the most common nutritional deficiency in the world. It is estimated that 20% to 25% of infants worlwide are affected by iron deficiency anemia.
COMPLICATIONS
1. Growth and development: developmental delays (birth to 5 years of age), decreased attention span, decreased social interactions, decreased performance on developmental tests
2. Muskuloskeletal: poor muscular development (long-term)
3. Gastrointestinal: contribution to lead poisoning (decreased iron enables gastrointestinal tract to absorb heavy metals more easily)
4. Nervous system: increased incidence of cerebral vascular accident in infants and children
LABORATORY AND DIAGNOSTIC TESTS
Refer to Appendix F for normal values and/or ranges of laboratory and diagnostic tests.
No single test is acceptable for detecting or diagnosing iron deficiency.
1. Hb concentration (before treatment)—decreased (one of most common tests used); indicates concentration of iron-containing protein Hb in circulating red blood cells
2. Hematocrit—decreased (one of most common tests used); indicates proportion of whole blood occupied by red blood cells
3. Mean corpuscular volume and mean corpuscular hemoglobin concentration—decreased, yielding microcytic, hypochromic anemia or small, pale red blood cells
4. Red blood cell distribution width (cutoff: 14%)
5. Erythrocyte protoporphyrin concentration—1 to 2 years: 80 mcg/dl of red blood cells
6. Transferrin saturation—younger than 6 months: 15 mcg/L or less
7. Serum ferritin concentration—less than 16%
8. Reticulocyte count (during treatment)—increase within 3 to 5 days of initiating iron therapy indicates positive therapeutic response
9. Hb concentration (with treatment)—return to normal value within 4 to 8 weeks indicates adequate iron and nutritional support
MEDICAL MANAGEMENT
Treatment efforts are directed toward prevention and intervention. Prevention includes encouraging parents to feed the infant only breast milk until the infant is between 4 to 6 months of age, to eat foods that are iron-rich, and to take iron-fortified prenatal vitamins (supplementation with approximately 1 mg/kg of iron per day). Iron supplementation should begin when infants are switched to regular milk. Therapy to treat iron deficiency anemia consists of a medication regimen.
1. By 6 months of age, breast-fed infants should receive 1 mg/kg of iron drops per day.
2. For breast-fed infants who were born prematurely or had low birth weight, 2 to 4 mg/kg (maximum of 15 mg) of iron drops daily is recommended starting at 1 month and continuing until 12 months of age.
3. Up to 12 months of age, only breast milk or iron-fortified infant formula should be used for liquid portion of nutrients.
4. Between 1 and 5 years of age, children should not consume more than 24 ounces of soy, goat’s, or cow’s milk daily.
5. Between 4 and 6 months of age, infants should have two or more daily servings of iron-fortified cereal.
6. By 6 months of age, child should have daily feeding of foods rich in vitamin C to improve iron absorption.
Iron is administered by mouth. All iron forms are equally effective (ferrous sulfate, ferrous fumarate, ferrous succinate, ferrous gluconate). Vitamin C must be administered simultaneously with iron (ascorbic acid increases iron absorption). Iron is best absorbed when taken 1 hour before a meal. Iron therapy should continue for a minimum of 6 weeks after the anemia is corrected to replenish iron stores. Injectable iron is seldom used unless small bowel malabsorption disease is present.
Adolescent girls should be encouraged to eat foods rich in iron. Other prevention strategies include comprehensive screening for, diagnosis of, and treatment of iron deficiency.
NURSING INTERVENTIONS
1. Encourage rest periods and naps.
2. Encourage developmentally appropriate play activities as tolerated.
3. Monitor child’s therapeutic and untoward effects from iron therapy.
4. Instruct parents about appropriate nutritional intake (see Medical Management section in this chapter).
5. Gather information about dietary history and eating behaviors.
6. Encourage breast-feeding, because breast milk iron is well absorbed.
7. Make referrals to physical and occupational therapy as needed.
8. Make referrals to psychologist or mental health specialist for cognitive and developmental testing as needed.
Discharge Planning and Home Care
1. Instruct about administering iron therapy (see item 2 under Nursing Interventions).
2. Instruct about meal planning and nutritional intake (see item 4 under Nursing Interventions).
3. Instruct about need for follow-up screenings and treatment approaches.
4. Instruct about outpatient physical and occupational therapy as needed.
5. Instruct about the need for cognitive and developmental follow-up as needed.
CLIENT OUTCOMES
1. Child’s skin color will improve.
2. Child’s pattern of growth will improve (as indicated on growth chart).
3. Child’s activity level will be appropriate for age.
4. Parents will demonstrate understanding of home treatment regimen (i.e., medication administration, diet with appropriate iron-rich foods).
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