1、Idiopathic ThrombocytopeniaPurpura（Immune Thrombocytopenia）特发性血小板减少性紫癜王 利重庆医科大学附属第一医院Outlines Definition Epidemiology Pathogenesis Signs and symptoms Laboratory Findings Diagnosis TreatmentDefinition ITP is an autoimmune disease with antibodies detectable可检测可检测against several platelet surface antige
2、ns 血小板表面抗原血小板表面抗原 low platelet count(thrombocytopenia)It causes a characteristic purpuric rash 紫癜性皮疹紫癜性皮疹 and an increasedtendency to bleedEpidemiologyThe incidence going up with the age get older,F:M=4:1 in adults,male dominant in children and senior1.Infection Bacteria,virus infection commonly Acu
3、te ITP:normally has upper respiratory infection 2-3weeks before onset Chronic ITP:Infection could be an induction 诱因诱因Pathogenesis2.Immunology In approximately 60 percent of cases,antibodies againstplatelets can be detected.Most often these antibodies areagainst platelet membrane glycoproteins 血小板膜糖
4、蛋白,and are of theimmunoglobulin G(IgG)type.Normal PLT can be destructed in the patient plasma.Immune suppressive drugs is effective to ITP patients.3.CTL induced platelet destructionThe stimulus for auto-antibody production in ITP is probablyabnormal T cell activity.Preliminary 初步 findings suggest t
5、hatthese T cells can be influenced by drugs that target B cells,such as rituximab 利妥昔单抗.Symptoms Signs include the spontaneous formation of bruises 淤青(purpura),especially on the extremities 四肢,bleeding from the nostrils 鼻孔 and/or gums 牙龈,and menorrhagia 月经过多(excessive menstrual bleeding 月经出血),any of
6、 which may occur if the platelet count is below 20,000 per l.A very low count(80%auto-curable Recurrent attack to yrsLaboratory Findings1.Platelet count2.Bone morrow examination3.PLT antibody:PA IgG4.Evans syndromeBlood count（x109/L）platelets 20 mainly 30-80WBC/RBC Normal NormalLifespan of PLTBM mor
7、phologyLaboratory findingsAcute ITPChronic ITP1-6 hrs 1-3 daysHypercellularityNo of megakaryocytes normal orincreased remarkableNormal of E,GAcute ITPChronic ITP(Chronic ITP,Wright stain,x200)(Megalokaryocyte,Gimsa stain,x400)Serum PA Ig or PA C3PA Ig,G or MPAC3 Evans syndromeITP with AIHADiagnosis1
8、.Clinical presentations of bleeding,no physical signsother than bleedings.2.Low platelet count repeatly3.Despite the destruction of platelets by splenic 脾的macrophages,the spleen is normally not enlarged4.Megakaryocytes in BM normal or increased with maturation 成熟 disorder5.One of the following five:
9、Corticosteriod effectiveSplenectomy 脾切除术 effectivePA Ig(+)PA C3(+)Lifespan 寿命 of PLT shortenedClassification of acute ITP or chronic ITPExclusion of secondary thrombocytopenia 血小板减少(differential diagnosis)1.Aplastic anemia 再生障碍性贫血2.Systemic lupus erythematosus 系统性红斑狼疮3.Drug induced thrombocytopenia
10、药物性血小板减少症4.Myelodysplastic syndrome 骨髓增生异常综合征5.Acute leukemia 急性白血病Treatment Splenectomy(removal of the spleen)Immunosuppressive agentsCyclosporin 环孢素Mycophenolate mofetil(MMF)骁悉Azathioprine 硫唑嘌呤Vincristine 长春新碱Three steps:CorticosteroidsStrategy Corticosteroids Thrombopoietin 促血小板生成素受体促血小板生成素受体 rec
11、eptor agonists Platelet transfusionExcept in an emergency,it is not recommended and usuallyunsuccessful in producing a long-term platelet count increase.Rituximab 利利妥昔单抗妥昔单抗a monoclonal 单克隆的 antibody against the B cell surface antigen CD20,maysometimes be an effective alternative to splenectomy.Introvenous immunoglobulin（IV Ig）Thank you
