Infections Hepatitis is the most common preceding infection, and posthepatitis marrow failure accounts for about 5% of etiologies in most series. Patients are usually young men who have recovered from a bout of liver inflammation 1 to 2 months earlier; the subsequent pancytopenia is very severe. The hepatitis is seronegative (non-A, non-B, non-C, non-G) and possibly due to a novel, as yet undiscovered, virus. Fulminant liver failure in childhood also follows seronegative hepatitis, and marrow failure occurs at a high rate in these patients. Aplastic anemia can rarely follow infectious mononucleosis, and Epstein-Barr virus has been found in the. | Chapter 102. Aplastic Anemia Myelodysplasia and Related Bone Marrow Failure Syndromes Part 4 Infections Hepatitis is the most common preceding infection and posthepatitis marrow failure accounts for about 5 of etiologies in most series. Patients are usually young men who have recovered from a bout of liver inflammation 1 to 2 months earlier the subsequent pancytopenia is very severe. The hepatitis is seronegative non-A non-B non-C non-G and possibly due to a novel as yet undiscovered virus. Fulminant liver failure in childhood also follows seronegative hepatitis and marrow failure occurs at a high rate in these patients. Aplastic anemia can rarely follow infectious mononucleosis and Epstein-Barr virus has been found in the marrow of a few patients some without a suggestive preceding history. Parvovirus B19 the cause of transient aplastic crisis in hemolytic anemias and of some PRCAs see below does not usually cause generalized bone marrow failure. Mild blood count depression is frequent in the course of many viral and bacterial infections but resolves with the infection. Immunologic Diseases Aplasia is a major consequence and the inevitable cause of death in transfusion-associated graft-versus-host disease GVDH which can occur after infusion of unirradiated blood products to an immunodeficient recipient. Aplastic anemia is strongly associated with the rare collagen vascular syndrome called eosinophilic fasciitis which is characterized by painful induration of subcutaneous tissues Chap. 316 . Pancytopenia with marrow hypoplasia can also occur in systemic lupus erythematosus. Pregnancy Aplastic anemia very rarely may occur and recur during pregnancy and resolve with delivery or with spontaneous or induced abortion. Paroxysmal Nocturnal Hemoglobinuria An acquired mutation in the PIG-A gene in a hematopoietic stem cell is required for the development of PNH but PIG-A mutations probably occur commonly in normal individuals. If the PIG-A mutant stem cell proliferates the
