神病學(xué)病毒性腦炎virus encephalitis

ViralEncephalitis病毒性腦炎ZhangXinqingXuanwuHospitalTheCapitalUniversityofMedicalSciencesEpidemiologyViralencephalitisoccursinallseasonsbutpeaksinsummerandearlyfall.ViralencephalitiscanoccuratanyagebuttheelderlyandinfantstendtohavemoresevereencephalitisClinicalmanifestationsTheonsetisusuallyabruptclinicalcourseprogressrapidlyover1to3daysthestrainofencephaliticvirusdeterminestheseverityofthesignsandsymptomthetableliststhemostcommonsignsandsymptomsClinicalmanifestationsClinicalmanifestationsLaboratoryfindingsThebloodleukocytecountisoftenelevatedlumbarpuncturefindingsalumbarpunctureshowsanormalorelevatedopeningpressuretheCSFcontains5to300WBC/mm3;50to200mg/dlofprotein;andnormalglucose;bacterialculturesaresterileLaboratoryfindingstheEEGisalwaysabnormalandshowsdiffusebackgroundslowingwithoccasionalepileptiformorelectrographicseizureactivityMRIstudiesoftenshowareasofincreasedsignalintensityonT2-weightedimages.TheCTscanmayappearnormalearly,andlatermayshowcerebraledema,necrosisorhemorrhageDiagnosisTheclinicaldiagnosisismadeon:acuteonsetoffeverprogressivementalstatusdeteriorationfocalneurologicalsignsandseizures(generalizedorfocal)CSFcontaininglymphocyticpleocytosis,normalglucoseandelevatedproteinabnormalMRIabnormalEEGDiagnosisThespecificetiologyoftheviralencephalitisismadeby:PCRassayofCSFCSFIgMantibodiestosomebutnotallvirusesvirusisisolationfromthroatorstoolforsomevirusesacuteandconvalescentserumantibodytitrerisebrainbiopsywithvirusculture;virusisseldomisolatedfromCSFMortalityrateandfrequencyofneurologicsequelae

Herpessimplexencephalitis(單純皰疹性腦炎)EtiologyHSVtype1encephalitisisthemostcommontypeinadults,thevirusmigratesalongnerveaxonstotrigeminalganglia,whereitpersistsinalatentformandmaybesubsequentlyreactivatedHSVtype2encephalitiscausesneonatalHSEbypassagethroughthebirthcanalofamotherwithactivegenitallesionsPathologyHSEtype1encephalitisisanacute,necrotizing,asymmetrichemorrhagicprocesswithlymphocyticandplasmacellreaction.Itusuallyinvolvesthemedialtemporalandfrontallobes.InclusionsmaybeseeninneuronsandgliaClinicalfindingsAcuteonsetRapidprogressionoverseveraldaysHeadache,fever,vomiting,fatigue,behavioraldisorders,memoryloss,aphasia,hemiparesisFocalorgeneralizedseizuresComa,evendeathCSFIncreasedpressureandlymphocyticcellmildproteinelevation,normalglucoseredbloodcellsmaybeseeninsomecasesviralantibodymaybedetectedbyELISAEEGdiffuseslowwaveactivitiesperiodicslow-wavecomplexesarisingfromoneorbothtemporallobesCTorMRIMRI:mayshowhyperintensityintemporallobe,frontallobes,insularcortex,orcerebralconvexityonT2-weightedimagesCT:islesssensitiveandmaybenormalduringearlyphaseandeabnormallatersimilartotheMRIT2-weightedMRIdemonstratedhyperintenselesioninthemesialtemporallobeHSE:MRIT1-weighteddemonstratedmiddlingintenseandhyperintenseinT2-weightT1-weightedMRIdemonstrateshypointenseandT2-weighteddemonstrateshyperintenselesioninthemesialtemporallobeDiagnosisHSEshouldbeclinicallysuspectediftheAcuteonset,clinicalsymptomsNeurologicalsignsEEGshowsacharacteristicpatternofhigh-voltage,periodic,lateralizingepileptiformdischarges(PLEDS)atarateof2-3Hzoriginatingfromthetemporallobe.MRIshowsfocalmedialtemporallobeabnormalityDiagnosisThediagnosisofHSEisconformedbydetectionoffragmentsofHSVDNAinCSForbrainbiopsyshowingdiffuseinflammationwithintranuclearinclusionbodiesidentificationofHSVparticlesbyelectronmicroscopyviralantigenidentificationbyimmunohistochemistryherpessimplexDNAfragmentsbyPCRisolationofHSVfromthetissueTreatmentandprognosistreatmentAcyclovirgivenintravenouslyatadosageof10mg/kgevery8hours,continuedfor14dayssymptomaticandsupportivetherapyprognosisupto50%untreatedcasesdieearlytreatmentwithacyclovircanreducethemortalityrateto20%to30%DifferentialdiagnosisBacterialmeningitis:signsofsystemicinfectionCSF:pressureiselevatedappearancerangesfromslightlyturbidtogrosslypurulentCSFwhitecellcountsof1000-10000/mlmaybeseenproteinconcentrationiselevatedglucoseisdecreasedGram-stainedsmearsofCSFcanidentifythecausativeorganismDifferentialdiagnosisTumorsubacuteorchroniconsetslowlyprogressivecourseCTscanorMRImaybehelpfulAcutedemyelinatedencephalopathyacuteorsubacuteonsetupperrespiratorytractinfectionandfevermaybepresentMRIshowslesioninwhitematterVaricella-zosterencephalitis帶狀皰疹病毒腦炎EtiologyAfterinfectionofvaricella-zostervirus(VZV),thevirusmigratestoganglia(latentinfection)Inconditionoflowerimmunity,thevirusisreactivatedandcausesencephalitisormeningitisPathologyMultifocalnecroticencephalomyelitisneuronaldegenerationdemyelinationvasculitisinvolvingmediumandsmallbloodvesselsoftheCNSresultinmultiplebraininfarctionmainlyinsubcorticalwhitematterClinicalfindingEncephalitismaybeseenincaseswithorwithoutskinrashfever,headache,vomitting,epilepsy,mentaldisorder,unconsciousness,focalneurologicsigns,cognitiveimpairmentsomecasesmaydevelopacutestrokesymptomsinseverecases,comaanddeathmayhappenLaboratoryfindingsCSF:

mildlyelevatedwhitecellcountsandproteinconcentrationparticularantibodycanbedetectedCT:

multifocalischemicandhemorrhagicnecrosismainlyfocusedonwhitematterDSA:pearlstenosisintheproximalpartofmiddlecerebralarteryDiagnosisandtreatmentDiagnosisdetectionofVZVDNAinCSFbyPCRassaydetectionofviralantibodybrainbiopsywithcharacteristichistopathologicchangestreatmentwithacyclovirfor14-21daysusually30mg/kgperdaydividedinto3dosesEnterovirusencephalitis腸道病毒腦炎MainetiologicagentsCoxsackievirusEchovirusEnteroviruspoliovirusClinicalfindingsAbacterialmeningitis:fever,severeheadache,nausea,vomitting,neckstiffness,Kernigsign(+)encephalitis:fever,headache,unconsciousness,epilepsy,fccalneurologicsignssomecasesmayshowmentalandbehavioraldisorders,ataxia,sensorydeficitsacutetransversemyelitis:abrupt,progressiveflaccidparalysis,urinaryretentionMyelitisLaboratoryfindingCSF:pressureisnormalorelevatedmildlymphocyticcellcountsincreaseproteinconcentrationismildlyelevatedparticularantibodycanbedetectedDiagnosisandtreatmentDefinitediagnosis:dependonisolationofCSFvirusTreatment:preventionofviralfecal-oraltransmissionsupportivetherapynospecificdrugsItisself-limiteddisease,andusuallyrecoversafter1weekProgressivemultifocalleukoencephalopathy(進(jìn)行性多灶性白質(zhì)腦病)EtiologyTheJCvirusisthecauseofPMLTheviruselatentinthekidneyandothersitesthevirusappearstoreactivatewhenimmunosuppressionfromAIDS,chronicleukemia,etcpresentsPathologyDiffuseandpachydemyelinationofwhitematterofthecerebralhemispheresometimesbrainstemandcerebellumarealsoinvolvedClinicalfindingsHemiparesis,aphasia,visualdeficits,dysarthriaanddementiaCommoninpatientswithAIDS,lymphomaorleukemia,carcinoma,orpharmacologicimmunosuppressionfollowingorgantransplantationSubacuteonset,progressivecourse,leadingtodeathin3-6monthsLaboratoryfindingsCSFisusuallynormalCTscanorMRIshowsmutifocalwhitematterabnormalitiesDiagnosisandtreatmentThediagnosisisestablishedbybrainbiopsywithchacteritichistopathologyappropriateclinicalsettingwithMRIorCTbrainlesionsissuggestiveJCvirusgenomefragmentsdetectedbyPCRassayissuggestivenoantiviraldrughasprovenefficacycytarabinemaybehelpfulmostpatientsdiewithin6monthsofdiagnosisSubacutesclerosingpanencephalitis(亞急性硬化性全腦炎)EtiologyandpathologyEtiologyItisachildhooddiseaseatypicalmeaslesinfectioniscausepathologydiffuseinflammatorylesionsinwhiteandgraymatter,andbrainstem,cerebellum,cervicalspinalcordcanalsobeinvolvedperivascularlymphocyticinfiltration,andmicroglialproliferationintranuclearorintracytoplasmicinclussionsmaybeseenClinicalfindingsChildrenless12yearsusuallyaffected,aboutahalfofcaseshaveinfectivehistoryofmeaslesthelatencyisusually5to8yearsslowonset,8to12monthscoursesfourphasesofclinicalcoursesClinicalfindingsfourphase