可逆性后部脑白质病

可逆性后部脑白质病第1页/共19页Posteriorreversibleencephalopathysyndrome(PRES)wasfirstreportedbyHincheyin1996.1.Itmayoccurduetoanumberofcausespredominantlymalignanthypertension,eclampsia,drugssuchastacrolimus,cyclosporine,autoimmunediseaseandpatientsundergoingorgantransplant.

Afterthetimelyandeffectivetreatmentoftheclinicalmanifestationandneuroimagingchangescanfullyrecover,neurologicalsequelaegenerallydoesnotexist第2页/共19页Themostcommonclinicalsymptomsandsignsareheadache,alteredalertnessandbehaviorchangesrangingfromdrowsinesstostupor,seizures,vomiting,mentalabnormalitiesincludingconfusionandabnormalitiesofvisualperception.Seizuresmaybeginfocallybutusuallybecomegeneralized.第3页/共19页ClassicallyPRES：characterizedbyhyperintensityonT2-weightedandFLAIRimagesbilaterallyandsymmetricallyintheparieto–occipitalregionswhichiscausedbysubcorticalwhitemattervasogenicedema.

第4页/共19页AtypicalPRES：otherregionsofthebrainareinvolvedexcepttheparieto-occipitallobes.Includesbrainstem,cerebellum,basalganglia,andfrontallobes.Atypicalimagingappearancesincludecontrastenhancement,hemorrhage,unilateralityandrestricteddiffusiononMRIandinvolvementofgraymatter.第5页/共19页1、Themorepopulartheorysuggeststhathypertensionleadstofailureofautoregulation,subsequenthyperperfusion,andvasogenicedema.2、Theothertheorysuggeststhatvasoconstrictionandhypoperfusionleadstobrainischemiaandsubsequentvasogenicedema.Therelativepaucityofsympatheticinnervationsintheposteriorbrainresultsinincreasedsusceptibilitytohyperperfusionandvasogenicedemaduringacutebloodpressureelevations.MostauthoritiesbelievethathypertensiveencephalopathyandeclampsiasharesimilarpathophysiologicmechanismsPathophysiology第6页/共19页A25-yearoldlady,primigravida；Onthe3rddayofpostpartumwithsuddenonsetofgiddiness,headache,vomiting,bilateralblurringofvisionfollowedbygeneralizedtonic-clonicseizure.HerBPwaswithinnormallimits.Bloodandurineroutineassayswerenormal,andnoproteinuriawasdetectedduringboththepregnancyandpuerperium.SheunderwentPersistentOccipito-posteriorpositionanddeliveredahealthymalebabyandherBPbothduringhersurgeryandpostpartumperiodwasnormal.Case1第7页/共19页Fig.1Case1:MRIbrainFLAIR(A),T2(B),Diffusion(C)andapparentdiffusioncoefficient(D)showingchangesinbilateralcaudate,anterior

limbofinternalcapsule,rightthalamusandbilateralparieto-occipitalsubcorticalwhitematterCase1第8页/共19页Fig.2:Case1:FollowupMRIbrainT2(A)andFLAIR(B)sameareasinFig.1beingnormal第9页/共19页A21-yearoldlady,primigravidawith30weeksgestation；Onthe6thdayofpostpartumwithh/osuddenonsetofheadache,vomiting,bilateralblurringofvisionfollowedbyrecurrentgeneralizedtonic-clonicseizure.ShehadregularANCcheckupandherBPwaswithinnormallimits.Bloodandurineroutinetestswerenormal,andnoproteinuriawasdetectedduringboththepregnancyandpuerperium.SheunderwentemergencyLSCSforPROMdeliveredastill-birthandherBPbothduringhersurgeryandpostpartumperiodwas第10页/共19页Fig.3:Case2:MRIbrainT2(A),diffusion(B)andapparentdiffusioncoefficient(C)showing

changesinbilateralcaudate,globuspallidus,putamenandbilateralparietooccipital

subcorticalwhitematterCase2第11页/共19页Fig.4:Case2:FollowupMRIbrainT2(A),diffusion(B)andapparentdiffusioncoefficient

(C)sameareasinFig.3beingnormal第12页/共19页FIGURE2.Atypicalpresentationofposteriorreversibleencephalopathysyndrome:Non-contrast(A)andpost-contrast(B)braincomputerizedtomographyindicatingahypodenselesionintheleftbasalgangliawithnocontrastenhancement;Brainmagneticresonanceimagingillustratingdiffusionrestrictionondiffusion-weightedimaging(C)andhighvaluesonapparentdiffusioncoefficient(D).AtypicaPRES第13页/共19页FIGURE3.Atypicalpresentationofposteriorreversibleencephalopathysyndrome.Thebraincomputerizedtomographyrevealedglobalbrainedemawithalargeleftparietalhematoma(A),andhemorrhageinthepons(B);theaxialmagneticresonancetomogramalsodemonstratesatypicalpresentationoftheareaswithincreasedsignalintensitiesintheponsbrainstem(C).第14页/共19页Changesindiffusion-weightedmagneticresonanceimaging(DWI)andapparentdiffusioncoefficient(ADC)inposteriorreversibleencephalopathyiswelldocumented,andcansuccessfullydifferentiatePRESfromearlycerebralischemia.DWIisthestudyofchoiceinPREStodiscriminatebetweenvasogenicandcytotoxicedema,thereby,beinghelpfulasascreeningimagingmethodologyinthesettingofischemiccomplicationsofPRESinidentifyingirreversibletissuedamage.ADCmappingcanbeusefultoruleoutotherconditionsthatcanmimicPRES,suchascentralpontinemyelinolysis.第15页/共19页CONCLUSIONItisofparticularimportancenottoexcludePRESasapossiblediagnosiswhenwehavetheappropriateclinicalpresentationwhichisnotaccomp