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1、Posteriorreversibleencephalopathysyndrome(PRES)Posteriorreversibleencephalopathysyndrome(PRES)wasfirstreportedbyHincheyin1996.1.Itmayoccurduetoanumberofcausespredominantlymalignanthypertension,eclampsia,drugssuchastacrolimus,cyclosporine,autoimmunediseaseandpatientsundergoi
2、ngorgantransplant.Afterthetimelyandeffectivetreatmentoftheclinicalmanifestationandneuroimagingchangescanfullyrecover,neurologicalsequelaegenerallydoesnotexistThemostcommonclinicalsymptomsandsignsareheadache,alteredalertnessandbehaviorchangesrangingfromdrowsinesstostupor,sei
3、zures,vomiting,mentalabnormalitiesincludingconfusionandabnormalitiesofvisualperception.Seizuresmaybeginfocallybutusuallybecomegeneralized.ClassicallyPRES:characterizedbyhyperintensityonT2-weightedandFLAIRimagesbilaterallyandsymmetricallyintheparieto–occipitalregionswhichisc
4、ausedbysubcorticalwhitemattervasogenicedema.AtypicalPRES:otherregionsofthebrainareinvolvedexcepttheparieto-occipitallobes.Includesbrainstem,cerebellum,basalganglia,andfrontallobes.Atypicalimagingappearancesincludecontrastenhancement,hemorrhage,unilateralityandrestricteddiff
5、usiononMRIandinvolvementofgraymatter.1、Themorepopulartheorysuggeststhathypertensionleadstofailureofautoregulation,subsequenthyperperfusion,andvasogenicedema.2、Theothertheorysuggeststhatvasoconstrictionandhypoperfusionleadstobrainischemiaandsubsequentvasogenicedema.Therelati
6、vepaucityofsympatheticinnervationsintheposteriorbrainresultsinincreasedsusceptibilitytohyperperfusionandvasogenicedemaduringacutebloodpressureelevations.MostauthoritiesbelievethathypertensiveencephalopathyandeclampsiasharesimilarpathophysiologicmechanismsPathophysiologyA25-
7、yearoldlady,primigravida;Onthe3rddayofpostpartumwithsuddenonsetofgiddiness,headache,vomiting,bilateralblurringofvisionfollowedbygeneralizedtonic-clonicseizure.HerBPwaswithinnormallimits.Bloodandurineroutineassayswerenormal,andnoproteinuriawasdetectedduringboththepregnancyan
8、dpuerperium.SheunderwentPersistentOccipito-posteriorpositionanddeliveredahealthyma