... (as in the immune leukopenias) Hematopoietic failuresyndromes are classified by dominant morphologic features ofthebonemarrow (Table 102-1) While practical distinction among these syndromes ... appear to evolve into another Many of these syndromes share an immune-mediated mechanism ofmarrow destruction and some element ofgenomic instability resulting in a higher rate of malignant transformation ... lymphomas ofbonemarrow Pancytopenia with Cellular BoneMarrow Primary bonemarrow diseases Secondary to systemic diseases Myelodysplasia Systemic Paroxysmal nocturnal lupus hemoglobinuria erythematosus...
... affected with equal frequency, but the age distribution is biphasic, with the major peak in the teens and twenties and a second rise in the elderly Etiology The origins of aplastic anemia have been ... among these disorders may not be possible Epidemiology The incidence of acquired aplastic anemia in Europe and Israel is two cases per million persons annually In Thailand and China, rates of five ... unfortunately, these relationships are not reliable in an individual patient and may not be etiologic In addition, while most cases of aplastic anemia are idiopathic, little other than history separates these...
... cause ofbonemarrowfailure Vast quantities of epidemiologic, clinical, and laboratory data link benzene to aplastic anemia, acute leukemia, and blood and marrow abnormalities The occurrence of ... drug may have been used to treat the first symptoms ofbonemarrowfailure (antibiotics for fever or the preceding viral illness) or provoked the first symptom of a preexisting disease (petechiae ... epidemic of aplastic anemia, its diminished use was not followed by a changed frequency ofmarrow failure) Risk estimates are usually lower when determined in population-based studies; furthermore, the...
... at the time of presentation [and PNH cells are also seen in MDS (see below)]; frank hemolysis and thrombotic episodes occur in patients with large PNH clones (>50%) Functional studies ofbonemarrow ... diagnosis of aplastic anemia may suffer from hemolytic PNH years after recovery of blood counts One popular but unproven explanation for the aplastic anemia/PNH syndrome is selection ofthe deficient ... nails, reticular hyperpigmentation, and the development of aplastic anemia during childhood The X-linked variety is due to mutations in the DKC1 (dyskerin) gene; the more unusual autosomal dominant...
... A Normal bonemarrow biopsy B Normal bonemarrow aspirate smear Themarrow is normally 30–70% cellular, and there is a heterogeneous mix of myeloid, erythroid, and lymphoid ... biopsy D Marrow smear in aplastic anemia Themarrow shows replacement of hematopoietic tissue by fat and only residual stromal and lymphoid cells An intrinsic stem cell defect exists for the constitutional ... proportion of patients with aplastic anemia, and mutations in genes ofthe telomere repair complex (TERC and TERT) can be identified in some adults with apparently acquired marrowfailure and...
... gentleness to avoid trauma; these will often show bleeding from the cervical os and blood in the stool Pallor ofthe skin and mucous membranes is common except in the most acute cases or those ... some ofthe T cells may recognize true self-antigens The rarity of aplastic anemia despite common exposures (medicines, hepatitis virus) suggests that genetically determined features ofthe immune ... expression on CD34 cells, leading to apoptotic cell death; localization of activated T cells to bonemarrow and local production of their soluble factors are probably important in stem cell destruction...
... replacement ofthe absent hematopoietic cells (and the immune system) by stem cell transplant, or it can be ameliorated by suppression ofthe immune system to allow recovery ofthe patient's residual bone ... if the physical examination ofthe abdomen is unsatisfactory MRI may be helpful to assess the fat content of a few vertebrae in order to distinguish aplasia from MDS Diagnosis The diagnosis of ... straightforward, based on the combination of pancytopenia with a fatty, empty bonemarrow Aplastic anemia is a disease ofthe young and should be a leading diagnosis in the pancytopenic adolescent...
... laboratory diagnosis of PNH can generally be made at the time of presentation of aplastic anemia by flow cytometry; recovered patients may have frank hemolysis if the PNH clone expands Bonemarrow examinations ... generally apparent within months of treatment Most recovered patients continue to have some degree of blood count depression, the MCV remains elevated, and thebonemarrow cellularity returns toward ... a leukocyte count adequate to prevent infection) in about 50% of patients The addition of cyclosporine to either ALG or ATG has further increased response rates to about 70% and especially improved...
... Other, more restricted forms ofmarrowfailure occur, in which only a single circulating cell type is affected and the aregenerative marrow shows corresponding absence or decreased numbers of ... Agranulocytosis, the most frequent of these syndromes, is usually a complication of medical drug use (with agents similar to those related to aplastic anemia), either by a mechanism of direct chemical ... Hand washing, the single best method of preventing the spread of infection, remains a neglected practice Nonabsorbed antibiotics for gut decontamination are poorly tolerated and not of proven value...
... associations with immune system diseases A small minority of cases occur with a thymoma More frequently, red cell aplasia can be the major manifestation of large granular lymphocytosis or may occur in ... malignancies (and more rarely other hematologic diseases) Paraneoplastic to solid tumors Connective tissue disorders with immunologic abnormalities Systemic lupus erythematosus, juvenile rheumatoid ... Self-limited Transient erythroblastopenia of childhood Transient aplastic crisis of hemolysis (acute B19 parvovirus infection) Fetal red blood cell aplasia Nonimmune...
... failuresyndromes A Giant pronormoblast, the cytopathic effect of B19 parvovirus infection ofthe erythroid progenitor cell B Uninuclear megakaryocyte and microblastic erythroid precursors typical of ... individuals, the temporary cessation of red cell production is not clinically apparent, and skin and joint symptoms are mediated by immune complex deposition Figure 102-2 Pathognomonic cells in marrowfailure ... precursors typical ofthe 5q– myelodysplasia syndrome C Ringed sideroblast showing perinuclear iron granules D Tumor cells present on a touch preparation made from themarrow biopsy of a patient with...
... appearing) and usually cellular bone marrow, and by consequent ineffective blood cell production A clinically useful nosology of these entities was first developed by the French-American-British ... erythropoietin therapy should be treated with immunosuppression and withdrawal of erythropoietin Myelodysplasia Definition The myelodysplasias (MDSs) are a heterogeneous group of hematologic ... (CMML) The (RAEB-t), World Health and chronic Organization classification (2002) recognizes that the distinction between RAEB-t and acute myeloid leukemia is arbitrary and groups them together...