Megaloblastic Anemia Complicated by Parvovirus B19 Induced Erythroblastopenia: A Case Report

Human parvovirus B19 is a known etiological agent for aplastic crisis in patients with chronic hemolysis and immunodeficiencies. The aplastic state caused in healthy children and adults is usually transient as compared to the more severe form seen in at risk population. Here we present a case of adult immuno-competent male with megaloblastic anemia complicated by aplastic crisis induced by parvovirus B19. A 23 year old male on treatment for megaloblastic anemia, presented with breathlessness, weakness and mild hepatomegaly. Laboratory investigations revealed an Hb-5.7g/dl, reticulocyte count-0.13% and absolute 6 reticulocyte count of 0.00 × 10 /µL. His serum vitamin B12 levels were 974 pg/ml. Bone marrow studies were done to evaluate the cause. Aspiration smears showed erythroid suppression with large proerythroblasts having vacuolated cytoplasm and eosinophilic intranuclear inclusions (Lantern cells). Biopsy showed proerythroblasts with nucleomegaly, pale chromatin and eosinophilic intranuclear inclusions, morpho-logically suggestive of parvovirus infection. Parvovirus B19DNA was isolated by TaqMan PCR. Patient was managed by red blood cell transfusion to which he responded well. Aplastic crisis due to parvovirus B19 has been reported in patients with sickle cells anemia, thalassemia, haematological malignancies, transplant recipients and acquired immunodeficiency states. Development of erythroblastopenia due to parvovirus in background of nutritional anemia is unusual. A bone marrow examination in such a scenario helps to exclude causes like myelodysplastic syndrome, lympho-proliferative disorder and provides clues for diagnosis of parvovirus infection which is a treatable etiology.