Parvo B19 and Anaemia: The Various Profiles – A Mini Review

Abstract

Introduction: Parvovirus 19 (Parvo B19) is a single stranded DNA virus which predominantly affects school-aged children, parents of such children and adults who are working in day care centres or schools. Individuals with underlying haemoglobinopathies, haemophilia, immunocompromised, malignancy and pregnancy states are at a higher risk of infection. This virus has been associated with multiple clinical manifestations including erythema infectiosum, arthopathy, fetal cardiomyopathy and hydrops fetalis. However, one of the most significant complications is the anaemia caused in the adult population. This includes pure red cell aplasia and transient aplastic crisis (TAC). Review: Pure red cell aplasia occurs predominantly in patients with immunocompromised states. The aplasia characteristically presents with a chronic or recurrent severe normocytic normochromic anaemia with reticulocytopaenia. The bone marrow reveals an absence of red-cell precursors or with the presence of giant pro-normoblasts with intra-nuclear inclusions. The condition is effectively managed using packed red cell transfusions, based on the degree of anaemia, and with intravenous immunoglobulin at 1g/kg over a period of 2 days or, more preferably, 500mg/kg over 5 days. The majority of patients respond after 1-3 doses. Correction of the underlying patient risk factors is vital. TAC occurs more frequently in patients with underlying red-cell abnormalities. This presents with a one to two week severe anaemia with variable smear and cellular findings varying from microcytic hypochromic to normocytic normochromic. Additionally, there is a reduced reticulocyte percentage and index. Packed red cell transfusion and correction of the underlying risk factor are often sufficient for the management of anaemia. The addition of immunoglobulin administration, 500mg/kg over 5 days, may be needed for patients who are immunocompromised. Conclusion: Parvovirus B19 remains a prevalent and prominent virus associated with multiple medical conditions particularly in immunocompromised states such as that of HIV, as well as erythrocyte disorders. Clinically, the virus has a plethora of presentations, two of which are severe anaemias: transient aplastic crisis and pure red cell aplasia. These conditions may be effectively and successfully managed with intravenous packed red-cell transfusions, intravenous immunoglobulins and by addressing of the underlying patient risk factors.