徐建民－特发性血小板减少性紫癜.ppt

DISORDERS OF HEMOSTASIS Dept.of Hematology ZhongShan Hospital,FuDan University Prof. JlAN-MIN XU General Considerations Disorders of hemostasis defects in platelet number or function problems in fibrin clot (coagulation) Bleeding due to platelet disorders is typically mucosal or dermatologic include epistaxis, gum bleeding, menorrhagia, gastrointestinal bleeding, purpura, and petechiae Thrombocytopenic Purpura Dept.of Hematology ZhongShan Hospital,FuDan University Prof. JlAN-MIN XU Brief 1.definition：bleeding of skin、mucous and organs 2.cause： （1）production ：drug, tumor, infection, radiation （2）destruction ：ITP,DIC,TTP （3）abnormal distribution：splenomegaly 3.classification：primary ,secondary IDIOPATHIC (AUTOIMMUNE) THROMBOCYTOPENIC PURPURA (ITP) General Considerations ITP is an autoimmune disorder in which an IgG autoantibody is formed that binds to platelets It is not clear which antigen on the platelet surface is involved. Although the antiplatelet antibody may bind complement, platelets are not destroyed by direct lysis General Considerations Rather, destruction takes place in the spleen, where splenic macrophages with Fc receptors bind to antibody-coated platelets Since the spleen is the major site both of antibody production and platelet sequestration, splenectomy is highly effective therapy General Considerations 1.definition：thrombocyte unrelated to a drug, an infection, or autoimmune disease is generally classified as ITP 2.character： shortened span of platelet increased megakaryocyte in bone marrow 3.classification：acute, chronic Mechanism 1.Immunity （1）acute： postviral infection immune complex (viral Ag and Ab) connect with platelet Fc-R viral components banding with platelet auto Ab generation （2）chronic：not affected by foreign Ag Mechanism 2.liver and spleen： （1）1/3 platelets are held within the