Iron Deficiency Anemia in Children

Background

• Iron deficiency is the most common nutritional deficiency worldwide and the most common cause of anemia in children.
• Iron deficiency anemia (IDA) is low hemoglobin or hematocrit due to insufficient iron stores and the major consequence of insufficient iron.
• It is most common in infants and children aged 6-20 months whose primary dietary intake is milk or unfortified formula; usually in quantities > 600 mL/day.
• Other major causes of IDA include chronic gastrointestinal blood loss and malabsorption.

Evaluation

• Iron deficiency in children is usually asymptomatic and often discovered during recommended anemia screening of high-risk infants and children, or during a workup for another complaint.
• The patient may exhibit pica (eating nonnutritive items such as soil).
• Pallor, failure to thrive, sleepiness, anorexia, tachycardia, stomatitis, and dysphagia may be present with severe anemia.
• Iron deficiency is associated with abnormal psychomotor development, breath-holding spells, restless legs syndrome, attention deficit hyperactivity disorder, and rarely with Tourette syndrome and stroke.
• Iron deficiency may be associated with lead poisoning.
• Iron deficiency is diagnosed by 2 of:
  • decreased serum ferritin (test of choice)
  • decreased transferrin saturation (iron/total iron binding capacity [TIBC])
  • increased free erythrocyte or zinc protoporphyrin levels
• Ferritin is the single best measure of iron stores in children but may be elevated with infection, inflammation, chronic disorders, hepatic disorders, and malignancy.
• An initial iron deficiency anemia workup (if necessary) includes complete blood count (CBC) with red cell indices, reticulocyte count, iron, TIBC, ferritin, transferrin saturation, and review of a peripheral blood smear.
• Commonly used age- and gender-based definitions of anemia for children and adolescents can be found from the World Health Organization/Centers for Disease Control and Prevention (WHO/CDC).
• IDA is the most likely diagnosis in a child with a low hemoglobin/hematocrit and a low mean corpuscular volume (MCV).
• IDA is presumptively diagnosed without further testing following a diagnostic/therapeutic trial of iron supplementation which demonstrates an increase of 1g/dL (10 g/L) in hemoglobin when remeasured 1 month following supplementation.
• Patients may be iron-deficient without having anemia.

Management

• Ferrous sulfate preparation 3-6 mg/kg/day of elemental iron for 4 months is recommended for infants and toddlers based on expert opinion, although ferrous gluconate and fumarate have similar efficacy and tolerability for equal doses of elemental iron.
• Constipation, nausea, vomiting, diarrhea, dark-colored stools, and abdominal pain are the major side effects of therapy.
• Increase dietary intake of iron-rich foods and decrease products that decrease iron absorption in iron-deficient patients.
• Parenteral iron is indicated for gastrointestinal disease interfering with absorption or intake, noncompliance or intolerance to oral therapy, refractory chronic bleeding, or hemoglobin < 6 in a patient unable or unwilling to have a blood transfusion.
• Exclusively or partially breastfed infants should receive 1 mg/kg/day of iron starting at 4 months and continued until complementary iron-containing foods are started (such as fortified rice cereal).
• Breastfed preterm infants should receive 2 mg/kg/day of iron by age 1 month and continue until taking iron-containing foods (unless the infant has received an iron load from multiple blood transfusions).
• Exclusively formula-fed preterm or term infants obtain adequate iron in the first 4 months as formula contains at least 2 mg/kg/day which remains sufficient when combined with complementary iron-containing foods.
• Children aged 1-3 years should take an iron supplement if not getting 7 mg/day through their diet.
• Universal anemia screening is recommended by the American Academy of Pediatrics (AAP) at age 12 months with additional screening/testing through age 3 years if at risk or anemic (hemoglobin < 11 mg/dL).