再生障碍性贫血英文

,Aplastic anemia(AA),Definition,Aplastic anemia is a life-threatening syndrome characterized by failure of the bone marrow to produce peripheral blood cells and their progenitors.,Etiology and pathogenesis,The major causes for aplastic anemia: 1.Infections (e.g. Hepatitis, Epstein-Barr virus and Parvovirus B19). 2.Radiation X rays, rays 3.Chemicals:benzene 4.Drugs:Chloramphenicol(氯霉素),Immune-Mediated injury is the main pathogenesis. In addition, absent or defective hematopoietic stem cells and abnormal bone marrow microenviroment can also cause aplastic anemia.,Clinical manifestation and classification,Clinical manifestation Anemia ,Bleeding and Infections are common symptomsClassification1.Severe Aplastic anemia（SAA）2.Non-severe Aplastic anemia（NSAA）,Physical Examination,1.Petechiae and ecchymoses are typical.,2.Pallor of the skin and mucous membranes is common.,Laboratory Studies,1.Blood Smear: Pancytopenia (anemia, leukopenia, and thrombocytopenia) is a universal presenting finding.,SAA blood smear,Normal peripheral blood smear,2.bone marrow biopsy:,Biopsy is superior for determination of cellularity and shows mainly fat under the microscope, with hematopoietic cells occupying 25% of the marrow space; in the most serious cases the biopsy is virtually 100% fat. It is required to establish the diagnosis.,A.Normal bone marrow biopsy. This specimen shows an abundance of hematopoietic cells, including Myeloid and erythroid precursors and Normal-appearing megakaryocytes,B. Aplastic anemia biopsy. This specimen shows few detectable hematopoietic cells, and those that can be seen (one small nest) are largely lymphocytes.,3.Bone marrow smear,The bone marrow is usually readily aspirated but dilute on smear, and the fatty biopsy specimen may be grossly pale on withdrawal; In severe aplasia the smear of the aspirated specimen shows only red cells, residual lymphocytes, and stromal cells.,D,D.Marrow smear in aplastic anemia. The marrow shows replacement of hematopoietic tissue by fat and only residual stromal and lymphoid cells.,C. Normal bone marrow aspirate smear. The marrow is normally 3070% cellular, and there is a heterogeneous mix of myeloid, erythroid, and lymphoid cells.,C,Reference standard of diagnosis for AA,1.Peripheral blood pancytopenia, reticulocyte percentage less than 0.01 and the ratio of Lymphocyte is increased. 2.Generally,without the liver and spleen enlargement.3.At least one area of hypoplasia in bone marrow. Non-hematopoietic cells increase .4. Elimination of other diseases which may cause pancytipenia such as PNH, MDS, acute arrest of hemopoiesis,etc.5.Common therapy for anemia is ineffective.,SAA laboratory criteria,To define SAA there must be at least two of the following: (1) absolute neutrophil count less than 0.5 109/L, (2) platelet count less than 20 109/L, or (3) reticulocytes less than 20 109/L. Non-severe AA:Patients not fulfilling the criteria for severe aplastic anaemia.,Treatment,Hematopoietic Stem Cell Transplantation This is the best therapy for the young patient with a fully his