Anemia at the Extremes of Life: Congenital Hemolytic Anemia

Abstract

Congenital hemolytic anemia is an important etiology to consider in the differential diagnosis of pediatric anemia, especially in patients presenting with neonatal hyperbilirubinemia requiring phototherapy or exchange transfusion. It results from inherited or de novo genetic defects that affect the function, shape, or stability of the red blood cell, resulting in red blood cell destruction, primarily via extravascular mechanisms. The main categories of congenital hemolytic anemia include the hemoglobinopathies, red blood cell membrane defects, and red blood cell enzyme defects. Clinical manifestations range from mild, compensated, asymptomatic anemia to transfusion-dependent anemia with extramedullary hematopoiesis. Laboratory evaluation usually reveals a reticulocytosis and negative direct antiglobulin testing, with or without abnormal red blood cell morphology. The typical findings of acute hemolysis, including decreased haptoglobin and increased LDH, might not always be present. Diagnosis depends on family history, drug or infection exposure, and the constellation of clinical findings. Treatment is dictated by the diagnosis, the degree of anemia, and the overall clinical status of the patient.