Anemia in Children

Background

• Anemia is commonly defined in children as a hemoglobin level ≥ 2 standard deviations below normal for age and gender.
  • Anemia is a common condition in children, with a global prevalence of 43% in children < 5 years old according to the World Health Organization's most recent analysis in 2011.
  • Iron deficiency is the most common cause of anemia in children, but a wide range of inherited and acquired etiologies must be considered.
• Anemia is often asymptomatic and may be detected on screening or during evaluation for other conditions.
• It can also cause acute symptoms and may be associated with long-term neurocognitive sequelae.
• The approach to anemia in children is directed toward identifying the underlying cause in order to enable treatment that will improve symptoms (if present) and avoid or reduce short- and long-term complications.

Evaluation

• Perform a thorough history and physical exam including assessing for:
  • common signs of anemia such as fatigue, pallor, decreased appetite, and headache
  • signs that may indicate severe anemia such as tachycardia, tachypnea, and hypotension
  • findings that may suggest an underlying cause, for example jaundice (suggests hemolysis), pica (may suggest iron deficiency), or dysmorphic features
• A complete blood count (CBC) is the usual initial diagnostic test.
  • A hemoglobin level ≥ 2 standard deviations below normal for age and gender confirms anemia.
  • Evaluate the mean corpuscular volume (MCV) in order to classify the anemia as microcytic, normocytic, or macrocytic.
  • Additional testing to consider includes a reticulocyte count, peripheral blood smear, and condition-specific testing as indicated based on the suspected underlying cause.
• Evaluation of microcytic anemia.
  • A trial of oral iron supplementation may be sufficient for diagnosing iron deficiency in children with mild anemia and low dietary iron intake. A hemoglobin increase of > 1 g/dL (10 g/L) confirms the diagnosis.
  • In other children or if unresponsive to iron supplementation, perform iron studies, and consider hemoglobin electrophoresis (to detect thalassemia or other hemoglobinopathy) and lead level.
• Evaluation of normocytic anemia.
  • Obtain a reticulocyte count and peripheral blood smear.
  • If the reticulocyte count is high, assess for hemolysis.
    • For hemolytic anemia, evaluate the peripheral smear and perform additional testing as indicated (based on clinical presentation and suspected underlying cause) to identify congenital enzymopathies, membranopathies, and hemoglobinopathies, and autoimmune hemolytic anemias.
    • For nonhemolytic anemia, consider assessments for blood loss and/or hypersplenism.
  • If the reticulocyte count is low, consider testing for
    • anemia of inflammation
    • liver or kidney disease
    • endocrine disorders
    • bone marrow disorders (such as leukemia or myelofibrosis), especially if there are abnormalities seen on a peripheral smear
• Evaluation of macrocytic anemia:
  • Assess the peripheral blood smear for hypersegmented neutrophils (indicative of megaloblastic anemia).
  • For megaloblastic anemia, assess for folate and vitamin B12 deficiencies.
  • For nonmegaloblastic anemia, assess the reticulocyte count.
    • If the reticulocyte count is low, assess for bone marrow disorders, liver disease, or hypothyroidism.
    • If the reticulocyte count is high, assess for hemolysis or hemorrhage.
• Refer to pediatric hematologist if cause remains unclear after testing.

Management

• Emergency management of children with anemia who are hemodynamically unstable:
  • Assess for sources of active bleeding and control bleeding if possible.
  • Consider blood transfusion based on overall clinical status, not just hemoglobin level.
    • Consider fluid resuscitation with crystalloids if needed while awaiting transfusion.
    • In life-threatening situations, uncross-matched blood may be used until fully cross-matched blood is available.
• General management depends on the underlying etiology.
  • Treat the underlying cause if possible, for example:
    • nutritional supplementation to correct iron, vitamin B12, or folate deficiency
    • removal of toxin or trigger, such as lead abatement for lead poisoning or drug discontinuation/replacement for drug-induced immune hemolytic anemia
  • Consider other definitive treatments as appropriate, for example:
    • hormone replacement therapy for endocrine disorders
    • corticosteroids for autoimmune hemolytic anemia
    • antibiotics or antiviral medications for infection
    • hematopoietic stem cell transplantation (HSCT) for primary myelofibrosis, aplastic anemia, or sideroblastic anemia
  • Consider supportive measures as needed such as red blood cell transfusion and erythropoiesis-stimulating agents.