Iron Deficiency Anemia
A reduction in hemoglobin production due to an insufficient supply of iron that results in a microcytic, hypochromic anemia
- Iron deficiency is the most common nutritional deficiency of children.
- Leading cause of anemia among infants and children in the United States
- Most commonly seen in children ages 9 months to 3 years and in teenage girls
- Prevalence is variable depending on socioeconomic status, availability of iron-fortified formulas, and prevalence and duration of breastfeeding.
- Prevalence of iron deficiency anemia in United States is generally between 1% and 5% of children.
- Low socioeconomic status
- Certain ethnic groups (e.g., Southeast Asian) may be at increased risk due to dietary practices.
- History of prematurity
- Maintain breastfeeding for the first 5 to 6 months of life if possible.
- Breast milk has lower iron concentration than formula, but iron in breast milk is more bioavailable (50% vs. 10%).
- Iron supplementation
- 1 mg/kg/24 h for infants who are exclusively breastfed beyond 4 months
- 2 mg/kg/24 h by 1 month of life for low-birth-weight and premature infants who are breastfed because of poor iron stores and increased growth rate
- Iron-fortified formula for the first 12 months of life for infants who are not breastfed
- Encourage iron-enriched cereal when infants are started on solid food.
- Screen hemoglobin level at periodic intervals.
- The American Academy of Pediatrics (AAP) recommends screening at 12 months, 1 to 3 years old, and adolescents as well as annually in menstruating females.
- Centers for Disease Control and Prevention (CDC) recommends screening high-risk groups annually between ages 2 and 5 years and all menstruating women every 5 to 10 years.
- Iron is required for oxygen transport by hemoglobin.
- Iron absorption and distribution is regulated by hepcidin, a peptide hormone secreted by liver, macrophages, and adipocytes.
- Iron is absorbed primarily in the duodenum.
- Iron deficiency develops because of an inadequate supply or increased demand for iron or a combination of these.
- Sequential stages of iron deficiency
- Depletion of iron stores: reflected by low serum ferritin and absent bone marrow stores
- Iron-deficient erythropoiesis: near-normal number of red blood cells (RBCs) produced, but they have abnormal hemoglobin synthesis with wide distribution in RBC size
- Iron deficiency anemia: microcytosis evident
- Causes of inadequate supply include dietary deficiency and malabsorption.
- Dietary deficiency in infants and young children results from introduction of cow’s milk prior to age 12 months, exclusive breastfeeding beyond age 6 months without iron supplementation, and excessive cow’s milk intake (>24 oz/24 h).
- Malabsorption results from surgical resection of intestine or celiac disease.
- Certain foods impair iron absorption (tannins in tea and coffee, phytates).
- Causes of increased demand include rapid growth and blood loss.
- Periods of rapid growth include infancy (especially low-birth-weight and premature infants) and adolescence.
- GI blood loss is most common and includes cow’s milk enteropathy (seen in infants), inflammatory bowel disease (IBD), and bleeding from Meckel diverticulum.
- Other etiologies of blood loss include perinatal loss, menorrhagia, pulmonary hemosiderosis, and hematuria.
- Several studies showed an association of obesity and iron deficiency; exact pathophysiologic mechanisms for this association are still under investigation.
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