Chapter 209: Iron Deficiency Anemia

Patient Story

A 24-month-old well appearing girl who is at the 50th percentile for height and 95th percentile for weight is being evaluated by her pediatrician. Her vital signs reveal a heart rate of 150 per minute, blood pressure 85/50 mm Hg, and respiratory rate of 15 per minute. She is noted to be an active toddler sucking on a bottle and upon questioning the mother reveals that the girl drinks 38 ounces of whole milk a day. She is not jaundiced or icteric but the pediatrician notes that she has conjunctival pallor (Figure 209-1). No hepatosplenomegaly is appreciated. Because of the conjunctival pallor and the dietary history, the pediatrician obtains a complete blood count, which shows a white blood cell count of 5100/mm3, hemoglobin 6.1 g/dL, and platelet count of 499,000/mm3. The lab reports microcytosis, hypochromia, mild anisocytosis, and polychromasia. There is no basophilic stippling. A diagnosis of iron deficiency anemia is made and the girl is treated with oral ferrous sulfate. The pediatrician suggests that the amount of milk intake should be limited to 20 ounces per day. One month later, her hemoglobin increased to 8 g/dl and she is continued on iron supplementation for 3 months after her hemoglobin is normal for age.

Introduction

Iron deficiency is the most common cause of anemia in the United State and worldwide.¹ Although iron deficiency has decreased with the use of iron supplements and with iron fortification of foods, especially infant formula, it remains a common problem.

Epidemiology

• Iron deficiency is rare before 9 months of age in full term infants.

• Iron stores are usually high in the full-term newborn and sufficient until 4 to 6 months of age. Children between 9 and 18 months of age are at highest risk for developing iron deficiency due to rapid growth combined with insufficient intake.

• Iron deficiency anemia is present in 7 percent of toddlers aged 1 to 2 years and 9 percent of adolescent girls.²

• Risk factors include early introduction of cow’s milk and consumption of more than 24 ounces of day of milk per day.

• Iron deficiency anemia is frequently seen in toddlers with excessive milk intake. The iron in milk is poorly absorbed. Further, the child may forego intake of other calorie sources because he or she is full from the milk. In addition, the child may develop mild blood loss from the gastrointestinal tract associated with the excessive milk.

• Preterm infants are at increased risk for iron deficiency anemia because of lower iron stores at birth and greater requirements due to faster growth rate.

Etiology and Pathophysiology