Snapshot An 11-month-old Caucasian boy presents to the emergency department for severe fatigue. His symptoms progressively worsened to the point where he is unresponsive. On physical exam, the patient has a flat nasal bridge and triphalangeal thumbs. Laboratory testing is significant for an isolated macrocytic anemia, reticulocytopenia, and increased HbF. Genetic testing is pursued, which demonstrates a ribosomopathy. Introduction Clinical definition isolated anemia and reticulocytopenia due to a pure red cell aplasia (PRCA) Etiology may be due to congenital (e.g., Diamond-Blackfan anemia) or acquired (e.g., transient erythroblastopenia, paraneoplastic syndromes, and parvovirus B19 infection) causes Pure Red Cell Aplasia Cause Clinical Findings Laboratory Findings Treatment Diamond-Blackfan anemia (DBA) Typically occurs in infancy Congenital abnormalities growth retardation craniofacial abnormalities e.g., hypertelorism and a flat nasal bridge thumb abnormalities e.g., triphalangeal thumbs Predisposition to cancer acute myelogenous leukemia myelodysplastic syndrome Etiology congenital impairments affecting ribosome synthesis Macrocytic, normochromic, and non-megaloblastic anemia Reticulocytopenia Increased HbF Corticosteroids and blood transfusions Hematopoietic cell transplantation in patients unresponsive to steroids Transient erythroblastopenia of childhood (TEC) Transient/temporary red cell aplasia DBA is chronic The child is otherwise healthy Etiology unknown Normocytic anemia at the time of diagnosis Reticulocytopenia Patients typically recover 1-2 months without treatment RBC transfusions may be needed for disabling symptoms Parvovirus B19 Patients with an underlying hemolytic process may experience an aplastic crisis with parvovirus B19 infection e.g., sickle cell anemia, hereditary spherocytosis, and pyruvate kinase deficiency Etiology temporary cessation of RBC production with a viral infection of erythroid progenitors via a P-antigen receptor Proerythroblasts and absent erythroid precursors may be seen in the bone marrow Otherwise healthy children do not require treatment Patients with an underlying hemolytic process receive RBC transfusions for symptomatic anemia Paraneoplastic syndrome Hemoglobin decline in a patient who has not had a transfusion and previously responded to erythropoietin Etiology underlying malignancy can result in the production of anti-erythropoietin antibodies malignancies thymoma myelodysplastic syndromes Bone marrow aspirate severe erythroid hypoplasia very little RBC precursors Present anti-erythropoietin antibodies Transfusions for symptomatic anemia Discontinue recombinant erythropoietin (EPO) products Immunosuppression ?