English

Abstract

Anemia in children may arise from a wide variety of pathogenetic mechanisms that include congenital and acquired disorders. Often the diagnostic considerations include disorders that are not seen commonly in adults and lifelong disorders that arise in children and persist throughout life. Consideration of diverse causes of anemia such as red cell membrane disorders, red cell enzymopathies, congenital dyserythropoietic anemias, congenital sideroblastic anemias, and hereditary pure red cell aplasia (Diamond-Blackfan anemia), as well as infectious causes such as parvovirus B19 infection, often is required when diagnosing anemia in an infant or young child. Knowledge of these entities that are important causes of anemia in the pediatric population, including clinical manifestations and laboratory workup, will aid in recognition of the specific disease entities and effective workup of pediatric red cell disorders. Inherited and acquired red cell disorders in children include a diverse group of disorders that include red cell enzyme disorders, red cell membrane disorders, congenital dyserythropoietic anemia, sideroblastic anemia, hemoglobinopathies, and red cell aplasias. Most of these disorders are manifested in the child by anemia with hypoproliferative or hemolytic mechanisms underpinning the development of anemia. Hypoproliferative anemia arises secondary to decreased overall RBC precursors or ineffective erythropoiesis, suggesting an abnormality in bone marrow production or erythroid precursors. Conversely, the anemia may be hemolytic in nature, reflecting abnormalities in RBC structure or biologic function that affect RBC life span and are associated with normal to increased erythropoiesis. Clinical manifestations, RBC characteristics, specific laboratory testing, and bone marrow findings are all useful in trying to classify the cause of the anemia and define a specific disease process. INTRODUCTION: Pure red cell aplasia (PRCA) is an uncommon disorder in which maturation arrest occurs in the formation of erythrocytes. Erythroblasts are virtually absent in bone marrow; however, WBC and platelet production is normal. The anemia due to PRCA is usually normocytic but can be macrocytic. In 1922, Kaznelson recognized that this condition was a different entity from aplastic anaemia, which presents with pancytopenia. The characteristics of PRCA include a severe anemia, a reticulocyte count of less than 1%, and the presence of less than 0.5% mature erythroblasts in the bone marrow. The bone marrow is usually normocellular. The etiology of PRCA is heterogeneous. A congenital form of PRCA was initially described by Joseph in 1936 and by Diamond and Blackfan in 1938. Congenital PRCA is a lifelong disorder and is associated with physical abnormalities. PRCA can be transient and reversible. Transient erythroblastopenia of childhood (TEC) can occur after viral infections. PRCA due to medications is also often reversible when these medications are discontinued. PRCA due to infections is often reversible. In adults, most cases of chronic PRCA are idiopathic, and a cause cannot be established. Secondary PRCA occurs in patients with conditions such as autoimmune disorders, thymomas, hematologic malignancies,