医学专业英语课件_3.pptx

Case DiscussionHuang HonghuiDepartment of HematologyRen Ji HospitalCase Summaryn26 year-old,female patientnpersistent nasal bleeding for one day,have an upper respi-ratory infection 2 weeks previously.No fever,chills,nausea,vomiting,abdominal pain,or joint pain.nPE:multiple l-mm reddish spots on her lower extremities.No lymphadenopathy or hepatosplenomegaly.nNo excessive bleeding with menses,childbirth,prior epistaxis,easy bruisability,or bleeding into her joints.nNo family history of abnormal bleeding.nNot take any medication.Objects of AnalysisnLearn the clinical approach to bleeding disorders,specificly platelets disorders versus coagulation disorders.nLearn about the differential diagnosis of thrombocytopenia,specifically thrombocytopenic purpura versus other platelet disorders,such as thrombotic thrombocytopenic purpura(TTP),hemolytic uremic syndrome(HUS),or disseminated intravascular coagulation(DIC).nLearn about the treatment of ITP.Considerationnsuperficial petechiae and mucosal bleeding disordered primarymary hemostasis nlaboratory testing complete blood countprothrombin time(PT)screeningpartial thromboplastin time(PTT)Bone marrow smearAPPROACH TO SUSPECTED THROMBOCYTOPENIAHISTORYnLiver disease,uremia,malignancy,systemic lupus erythematousnMedications:over-the-counter products(aspirin)nFamily history of abnormal bleedingnHistory of epistaxis,menorrhagia,excessive prolonged bleeding from minor cuts,bruising,prolonged or profuse bleeding after dental extraction,excessive bleeding after major surgery or obstetric delivery,trauma followed by bleeding considered excessive relative to the injuryTiming of BleedingnIf bleeding following dental extraction is immediate and lasts for longer than 24 hours,a problem with primary hemostatic plug formation may be present.Therefore,this may suggest a platelet disorder.nIf initial hemostasis seemed normal but prolonged bleeding developed 2-3 days later,a problem in the coagulation phase is suspected.Type of BleedingnSpontaneous mucus membrane bleeding,such as gum bleeding,nose bleeding,and petechiae are suggestive of a vascular disorder,thrombocytopenia,or abnormal platelet function.nHemarthrosis,deep hematoma,and retroperitoneal bleeding are more likely to reflect a severe coagulation abnormality,such as hemophilia,if problems have been lifelongspontaneous inhibitor of factor VIII,if problems appear later in iife.Vascular DisordersnVascular purpura present with bleeding from mucus membranes and the appearance of petechiae but usually the platelet count and the coagulation profile(PT and PTT)are normalnHereditary hemorrhagic telangiectasiasinherited as an autosomal trait of high penetrance.the most common hereditary vascular disorder The physical exam will show the presence of telangiectasias.Causes of thrombocytopenia ndecreased platelet productionndecreased platelet survivalnsequestration(hypersplenism)ndilutionalSpurious ThrombocytopenianAutomated cell counters reports spurious thrombocytopenia in approximately 0.l%of patients.nThis is generally a result of platelet dumping after drawing blood into the anticoagulant ethylene diamine tetra acetate(EDTA).nConfirmationIdentifying platelet aggregates on peripheral blood smearUsing citrate or heparin as an anticoagulantImpaired platelet productionnInfiltration caused by malignancy or myelofibrosisnMarrow hypoplasiaChemicalsDrugsRadiationVirusesDecrease platelet survivalnimmune thrombocytopenia purpua(caused by IgG antibody against the platelets),ndrug-induced thrombocytopenic purpuransecondary immunologic purpura(as in lymphoma,lupus,infection with human immunodeficiency virus type 1)nposttransfusion purpura.nDisseminated intravascular coagulationnhemolytic uremic syndromencavernous hemangiomanacute infections ITPnAcute ITP early childhoodantecedent upper respiratory infectionself-limiting,usually resolves spontaneously within 3-6 months.nChronic ITPin adults,most likely to occur in women ages 20-40 years an insidious or subacute present.persist for months to Years,with uncommon spontaneous remission.Several immunologic disorders may mimic true ITP ndrug induced thrombocytopenic purpuraDiscontinuation of the medication should lead to improvement in the platelet count within a time frame consistent with the drugs metabolism.Many drugs are blown to cause thrombocytopenic purpura,such as quinidine and quinine,Sulfonamide,heparin,and gold compounds.nSLEnLymphomaLymphadenopathy splenomegalynHIV-1 infectionnPosttransfusion purpuraNonimmunologic disorders may mimic true ITPnDICnTTPDICnETIOLOGYSecondary to some other process:sepsis,trauma,metastatic malignancy,obstetric causesnCLINICAL COURSEcan be relatively mild indolent course,or severe llfe-threatening process;ongoing coagulation and fibrinolysis;can cause thrombosis or hemorrhage;consumption of coagulation factors is seen as prolonged PT and PTTDICnTREATMENTTreatment aimed at underlying cause.No proven specific treatment for the coagulation problem.If clotting,consider anticoagulate with heparin.If bleeding,replace factors and fibrinogen with fresh frozen plasma or cryoprecipitate.TTPnETIOLOGYMultiple causes,many seemingly trivial drugs/infection lead to endothelial injury and release of von Willebrand factor,triggering formation of mlcrovascular thrombi.nCLINICAL COURSEfeveraltered mental statesthrombocytopeniaMicroangiopathic hemolytic anemiaRenal failureTTPnTREATMENTPlasmapheresis(removal of the excess/abnormal vWF),most patients recovercorticosteroidsITPnETIOLOGYAntiplatelet antibody leading to platelet destructionnCLINICAL COURSEChildren:following a Viral illness with resolution.Adults:a more indolent course with progression and rarelys spontaneous resolution.Isolated thrombocytopenia,normal PT,PTT.Increased megakaryocytes on bone marrow aspiration.ITPnTREATMENTOral Corticosterolds,Splenectomy if resistant to steroids,ImmunosuppressantsIntravenous ImmmoglobulinAnswersnMost likely diagnosis:Immune thrombocytopenic purpuranBest initial treatment:Oral corticosteroidsComprehension QuestionsnA 50-year-old man has been treated for rheumatoid arthritis for many years.He is currently taking corticosteroids for the disease.On examination,he has stigmata of rheumatoid arthritis and some fullness on his left upper abdomen.His platelet count is slightly low at 56,000/mm3.His WBC count is 3,100/mm3 and Hgb 9.Og/dL.Which of the following is the most likely etiology of the thrombocytopenia?A.Steroid inducedB.SequestrationC.Rheumatoid arthritis autoimmune induced D.Prior gold therapyComprehension QuestionsnA 30-year-old woman with ITP has been taking maximum corticosteroid doses and still has a platelet count of 20,000/mm3 and frequent bleeding episodes.Which of the following should she receive before her splenectomy?A.Washed leukocyte transfusion B.Intravenous interferon therapy C.pneumococcal vaccineD.Bone marrow radiotherapyCLINICAL PEARLSnBleeding abnormalities can be divided into primary hemostatic problems(platelet plug at time of injury)and secondary hemostasis(creation of a stable fibrin clot).nDisorders of primary hemostasis(thrombocytopenia or von Willebrand)are characterized by mucosal bleeding and the appearance of petechiae or superficial ecchymoses.CLINICAL PEARLSnDisorders of secondary hemostasis(coagulation factor deficiencies such as hemophilia)are usually characterized by the development of superficial ecchymoses,as well as deep hematomas and hemarthroses.nITP is a diagnosis of exclusion.Patients have isolated thrombocytopenia(i.e.,no red or white blood cell abnormalities),no apparent secondary causes such as systemic lupus erythematosus,HIV or medication-induced thrombocytopenia,and normal to increased numbers of megakaryocytes in the bone marrow.CLINICAL PEARLSnTreatment of ITPCorticosteroids are the initial treatment of ITP.Patients with more severe disease may be treated with intravenous immunogiobulin(IVIG);chronic refractory cases are treated with splenectomy.Thanks!