中枢神经系统感染.ppt

VIRALMENINGITIS轴突传播：neuronalspreadofthevirusbyaxonaltransport(eg,herpessimplex,rabies狂犬病病毒);自身免疫性感染后脱髓鞘：autoimmunepostinfectionsdemyelination脱髓鞘(eg,varicella水痘病毒,influenza).,Pathologicchangesinviralmeningitisconsistofaninflammatorymeningealreactionmediatedbylymphocytes.,病毒性脑膜炎的病理改变是由淋巴细胞介导的炎性脑膜反应。,Encephalitisischaracterizedbyperivascularcuffing,lymphocyticinfiltration,andmicroglialproliferationmainlyinvolvingsubcorticalgraymatterregions.Internuclearorintracytoplasmicinclusionsareoftenseen.病毒性脑炎的病理改变特点是血管周围套袖样改变、淋巴细胞浸润，以及累及皮层下灰质的小胶质增生，并经常可见到核浆或细胞浆内包涵体。,Clinicalfindings-symptomsandsigns,Clinicalmanifestationsincludefever,headache,neckstiffness,photophobia畏光,painwitheyemovement,andmildimpairmentofconsciousness.Patientsusuallydonotappearasillasthosewithbacterialmeningitis.Systemicviralinfectionmaycauseskinrash,pharyngitis咽炎,lymphadenopathy淋巴结病,pleuritis胸膜炎,carditis心肌炎,jaundice黄疸,organomegaly器官肿大,diarrhea腹泻,ororchitis睾丸炎,andthesefindingsmaysuggestaparticularetiologicagent病原体.,Becauseviralencephalitisinvolvesthebraindirectly,markedalterationsofconsciousness,seizures,andfocalneurologicsignscanoccur.Whensignsofmeningealirritation脑膜刺激征andbraindysfunctioncoexist共存,theconditionistermedmeningoencephalitis脑膜脑炎.,Laboratoryfindings,CSFanalysisisthemostimportantlaboratorytest.CSFpressureisnormalorincreasedalymphocyticormonocyticpleocytosis脑脊液细胞数增多ispresent,withcellcountsusuallylessthan1000/ml.(highercountscanbeseeninlymphocyticchoriomeningitis脉络丛脑膜炎orherpessimplexencephalitis.)Apolymorphonuclear多形核白细胞pleocytosiscanoccurearlyinviralmeningitis,whileredbloodcellsmaybeseenwithherpessimplexencephalitis.,Proteinisnormalorslightlyincreased(usually80120mg/dL).Glucoseisusuallynormal,butmaybedecreasedinmumps腮腺炎,herpeszoster带状疱疹,orherpessimplexencephalitis.Gramsstainandbacterial,fungal,andacid-fastbacillius(AFB)culturesarenegative.Oligoclonalbands寡克隆区带andCSFproteinelectrophoresis电泳abnormalitiesmaybepresent.Anetiologicdiagnosiscanoftenbemadebyvirusisolation,polymerasechainreaction,oracute-andconvalescentphase恢复期CSFantibodytiters抗体滴度.,Bloodcountsmayshowanormalwhitecellcount,leukopenia白血球减少症,ormildleukocytosis白细胞增多.Serumamylase血清淀粉酶isfrequentlyelevatedinmumps腮腺炎;abnormalliverfunctiontestsareassociatedwithbothhepatitisviruses肝炎病毒andinfectiousmononucleosis单核细胞增多症.,TheEEGisdiffuselyslow,especiallyifthereisdirectcerebralinvolvement.,Diagnosis,Differentialdiagnosis,Thedifferentialdiagnosisofmeningitiswithmononuclearcellpleocytosisincludespartiallytreatedbacterialmeningitis治疗不彻底的细菌性脑膜炎aswellassyphilitic梅毒的,tuberculous结核性的,fungal,parasitic寄生物的,neoplastic肿瘤的,andothermeningitides脑(脊)膜炎.,EvidenceofsystemicviralinfectionandCSFwetmounts,stainedsmears,cultures,andcytologicexamination细胞学检查candistinguishamongthesepossibilities.Whenpresumedearlyviralmeningitisisassociatedwithapolymorphonuclear多形核白细胞pleocytosisoflessthan1000whitebloodcells/mLandnormalCSFglucose,oneoftwostrategiescanbeused.,ThepaitentcanbetreatedforbacterialmeningitisuntiltheresultsofCSFculturesareknown;Treatmentcanbewithheldandlumbarpuncture腰椎穿刺术repeatedin612hours.Ifthemeningitisisviralinorigin,thesecondsampleshouldshowamononuclearcellpleocytosis.,Adisorderthatmaybeclinicallyindistinguishablefromviralencephalitisistheimmune-mediatedencephalomyelitisthatmayfollowviralinfectionssuchasinfluenza,measles麻疹,orchickenpox水痘.Progressiveneurologicdisfunctiontypicallybeginsafewdaysaftertheviralillness,butcanalsooccureithersimultaneously同时发生oruptoseveralweekslater.,Neurologicabnormalitiesresultfromperivenous静脉周围的demyelination脱髓鞘,withoftenseverelyaffectsthebrainstem.TheCSFshowsalymphocyticpleocytosis脑脊液细胞数增多,usuallywithcellcountsof50150/mL,andmildproteinelevation.,Treatment,Exceptforherpessimplexencephalitis,whichisdiscussedseparatelynospecifictherapyforviralmeningitisandencephalitisisavailable.Corticosteroidsareofnoprovenbenefitexceptinimmune-mediatedpostinfectioussyndromes.,Headacheandfevercanbetreatedwithacetaminophen醋氨酚,butaspirinshouldbeavoided,especiallyinchildrenandyoungadults,becauseofitsassociationwithReyessyndrome.Seizuresusuallyrespondtophenytoin苯妥英钠orphenobarbital苯巴比妥.Supportivemeasuresincomatose昏睡的patientsincludemechanicalventilationandintravenousornasogastricfeeding鼻饲.,Prognosis,Symptomsofviralmeningitisusuallyresolvespontaneouslywithin2weeksregardlessofthecausativeagent,althoughresidualdeficits后遗症maybeseen.Theoutcomeofviralencephalitisvarieswiththespecificvirus-forexample,herpessimplexvirusinfectionsareassociatedwithseveremorbidityandhighmortalityrates.Mortalityratesashighas20%havealsobeenreportedinimmune-mediatedencephalomyelitis脑脊髓炎followingmeasles麻疹infections.,Herpessimplexvirus(HSV)encephalitis,HSVisthemostcommoncauseofsporadic散发的fatalencephalitisintheUnitedStates.Abouttwo-thirdsofcasespatientsover40yearsofage.Primaryherpesinfectionsmostoftenpresentasstomatitis口炎(HSVtype1)oravenereally性交的transmittedgenital生殖器eruption出疹(HSVtpye2).,Thevirusmigratesalongnerveaxons轴突tosensoryganglia神经节,whereitpersistsinalatentformandmaybesubsequentlyreactivated.ItisnotclearwhetherHSVtype1encephalitis,themostcommontypeinadults,representsaprimaryinfectionorareactivationoflatentinfection.,Neonatal新生儿的HSVencephaltisusuallyresultsfromacquisition获得oftype2virusduringpassagethroughthebrithcanalofamotherwithactivegenital生殖器的lesions.CentralnervoussysteminvolvementbyHSVtype2inadultsusuallycausesmeningitis,ratherthanencephalitis.,Pathology,HSVtpye1encephalitisisanacute,necrotizing引坏死的,asymmetric不对称的hemorrhagic出血性的processwithlymphocyticandplasmacell浆细胞reaction.Usuallyinvolvesthemedialtemporalandinferiorfrontallobes.Intranuclearinclusions核内包涵体maybeseeninneurons神经元andglia神经胶质.Patientswhorecover康复期mayshowcystic囊的necrosis坏死oftheinvolvedregions.,嗜酸性CowdryA型包涵体,ClinicalFinding-ASymptomsandSigns,Theclinicalsyndromemayincludeheadache,stiffneck,vomiting,behavioraldisorders,memoryloss,anosmia嗅觉丧失,aphasia,hemiparesis轻偏瘫,andfocalorgeneralizedseizures.,Activeherpeslabialis唇疱疹isseenoccasionally,butdoesnotreliablyimplicateHSVasthecauseofencephalitis.,HSVencephalitisisuauallyrapidlyprogressiveoverseveraldaysandmayresultincomaordeath.Themostcommonsequelae后遗症inpatientswhosurvivearememoryandbehaviordisturbances,reflectingthepredilection嗜好,偏爱ofHSVforlimbicstructures.,LaboratoryFindings,LaboratoryFindings-CSF,TheCSFinHSVtpye1encephalitismostoftenshowsincreasedpressurelymphocyticormixedlymphocyticandpolymorphonuclear多形核白细胞pleocytosis(50100whitebloodcells/mL)mildproteinelevation,andnormalglucose.Redbloodcells,xanthochromia黄变,anddecreasedglucoseareseeninsomecases.,LaboratoryFindings-VIRUS,ThevirusgenerallycannotbeisolatedfromtheCSF,butviralDNAhasbeendetectedbythepolymerasechainreaction聚合酶链反应insomecases.,HSV抗体检定,ELASA是现今国际上通用的HSV抗体检测方法。本方法采用双份血清和双份脑脊液作HSV-1抗体的动态检测。诊断标准：双份CSF抗体有增高趋势，滴度1:8以上；双份CSF抗体4倍以上升高；血与CSF的抗体比值40。,LaboratoryFindings-EEG,TheEEGmayshowperiodic周期的slow-wavecomplexesarisingfromoneorbothtemporallobes,LaboratoryFindings-CTMRI,CTscansandMRImayshowabnormalitiesinoneorbothtemporallobes.Thesecanextendtofrontalorparietalregions顶区andaresometimesenhancedwiththeinfusion注入ofcontrastmaterial造影剂.However,imagingstudiesmayalsobenormal.,Diagnosis,DifferentialDiagnosis,Thesymptomsandsignsarenotspecificforherpesvirusinfection.ThegreatestdiagnosticdifficultyisdistinguishingbetweenHSVencephalitisandbrainabscess脑脓肿,andthetowdisordersoftencannotbedifferentiatedonclinicalgroundsalone.,brainabscess,brainabscess,OtherCNSinfectionsandvasculitis血管炎canalsomimicHSVencephalitis.Deginitivediagnosiscanbemadebybiopsyofaffectedbrainareas,withthechoiceofbiopsysiteguidedbytheEEG,CT,orMRIfindings.However,beca