4/27/2015 HypertensiveEncephalopathy

http://emedicine.medscape.com/article/166129overview#a0104 1/3

HypertensiveEncephalopathyAuthor:IrawanSusanto,MD,FACPChiefEditor:MichaelRPinsky,MD,CM,Drhc,FCCP,MCCMmore...

Updated:Apr14,2015

BackgroundThetermhypertensiveencephalopathywasintroducedin1928todescribetheencephalopathicfindingsassociatedwiththeacceleratedmalignantphaseofhypertension.Thetermsacceleratedandmalignantwereusedtodescribetheretinalfindingsassociatedwithhypertension,asfollows:

Acceleratedhypertensionisassociatedwithgroup3KeithWagenerBarkerretinopathy,whichischaracterizedbyretinalhemorrhagesandexudatesonfunduscopicexaminationMalignanthypertensionisassociatedwithgroup4KeithWagenerBarkerretinopathy,whichischaracterizedbythepresenceofpapilledema,heraldingneurologicimpairmentfromanelevatedintracranialpressure(ICP)

Withadequatecontrolofhypertension,lessthan1%ofpatientsexperienceahypertensivecrisis.Ahypertensivecrisisisclassifiedaseitherahypertensiveemergencyorahypertensiveurgency,[1]asfollows:

Acuteorongoingvitaltargetorgandamage(eg,damagetothebrain,kidney,orheart)inthesettingofseverehypertensionisconsideredahypertensiveemergencyapromptreductioninbloodpressureisrequiredwithinminutesorhoursTheabsenceoftargetorgandamageinthepresenceofasevereelevationinbloodpressure(withdiastolicbloodpressurefrequentlyexceeding120mmHg)isconsideredahypertensiveurgencyareductioninbloodpressureisrequiredwithin2448hours

Acontinuumexistsbetweentheclinicalsyndromesofhypertensiveurgencyandemergencyhence,thedistinctionbetweenthe2syndromesmaynotalwaysbeclearandpreciseinpractice.[2]

Hypertensiveencephalopathyreferstothetransientmigratoryneurologicsymptomsthatareassociatedwiththemalignanthypertensivestateinahypertensiveemergency.Theclinicalsymptomsareusuallyreversiblewithpromptinitiationoftherapy.Intheevaluationofanencephalopathicpatient,itisvitaltoexcludesystemicdisordersandvariouscerebrovasculareventsthatmaypresentwithasimilarconstellationofclinicalfindings.

PathophysiologyTheclinicalmanifestationsofhypertensiveencephalopathyareduetoincreasedcerebralperfusionfromthelossofbloodbrainbarrierintegrity,whichresultsinexudationoffluidintothebrain.Innormotensiveindividuals,anincreaseinsystemicbloodpressureoveracertainrange(ie,60125mmHg)inducescerebralarteriolarvasoconstriction,therebypreservingaconstantcerebralbloodflow(CBF)andanintactbloodbrainbarrier.

Inchronicallyhypertensiveindividuals,thecerebralautoregulatoryrangeisgraduallyshiftedtohigherpressuresasanadaptationtothechronicelevationofsystemicbloodpressure.[3]Thisadaptiveresponseisoverwhelmedduringahypertensiveemergency,inwhichtheacuteriseinsystemicbloodpressureexceedstheindividualscerebralautoregulatoryrange,resultinginhydrostaticleakageacrossthecapillarieswithinthecentralnervoussystem(CNS).BrainMRIscanshaveshownapatternoftypicallyposterior(occipitalgreaterthanfrontal)brainedemathatisreversible.Thisusuallyistermedreversibleposteriorleukoencephalopathyorposteriorreversibleencephalopathysyndrome(PRES).[4]

Withpersistentelevationofthesystemicbloodpressure,arteriolardamageandnecrosisoccur.Theprogressionofvascularpathologyleadstogeneralizedvasodilatation,cerebraledema,andpapilledema,whichareclinicallymanifestedasneurologicdeficitsandalteredmentationinhypertensiveencephalopathy.

EtiologyThemostcommoncauseofhypertensiveencephalopathyisabruptbloodpressureelevationinachronicallyhypertensivepatient.Otherconditionsthatcanpredisposeapatienttoelevatedbloodpressureandcausethesameclinicalsituationincludethefollowing:

ChronicrenalparenchymaldiseaseAcuteglomerulonephritisRenovascularhypertensionWithdrawalfromhypertensiveagents(eg,clonidine)Encephalitis,meningitisPheochromocytoma,reninsecretingtumorsSympathomimeticagents(eg,cocaine,amphetamines,phencyclidine[PCP],andlysergicaciddiethylamide[LSD])EclampsiaandpreeclampsiaHeadtrauma,cerebralinfarctionCollagenvasculardiseaseAutonomichyperactivityVasculitisIngestionoftyraminecontainingfoodsortricyclicantidepressantsincombinationwithmonoamineoxidaseinhibitors(MAOIs)

EpidemiologyandPrognosis

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4/27/2015 HypertensiveEncephalopathy

http://emedicine.medscape.com/article/166129overview#a0104 2/3

Ofthe60millionAmericanswithhypertension,lessthan1%developahypertensiveemergency.Themorbidityandmortalityassociatedwithhypertensiveencephalopathyarerelatedtothedegreeoftargetorgandamage.Withouttreatment,the6monthmortalityforhypertensiveemergenciesis50%,andthe1yearmortalityapproaches90%.

Hypertensiveencephalopathymostlyoccursinmiddleagedindividualswhohavealongstandinghistoryofhypertension.Hypertensioningeneralismoreprevalentinmenthaninwomen.Thefrequencyofhypertensiveencephalopathyinvariousethnicgroupscorrespondstothefrequencyofhypertensioninthegeneralpopulation.Hypertensionismoreprevalentinblackpeople,exceedingthefrequencyinotherethnicminoritygroups.Theincidenceofhypertensiveencephalopathyislowestinwhitepeople.

PatientEducationReferpatientstoadietitiantoreducetheriskofvascularandhypertensivedisease.Encouragelifestylemodifications,includingsmokingcessation,increasingexercise,moderationofalcohol,andavoidanceoftobacco.

Educatepatientsaboutmedicationadherenceandcompliance,andstronglyemphasizetheneedformedicalcompliance.Explaintheeffectsofuncontrolledhypertension,includingthecomplicationsofpersistenthypertension.Informpatientsaboutsignsofacutetargetorgandamage,includingvisualchanges,persistentheadaches,andneurologicalchanges.

ContributorInformationandDisclosuresAuthorIrawanSusanto,MD,FACPClinicalProfessorofMedicine,DirectorofPulmonaryConsultationandProcedures,DivisionsofInterventionalPulmonologyandCriticalCare,UniversityofCalifornia,LosAngeles,DavidGeffenSchoolofMedicine

IrawanSusanto,MD,FACPisamemberofthefollowingmedicalsocieties:AmericanCollegeofPhysiciansAmericanSocietyofInternalMedicine

Disclosure:Nothingtodisclose.

Coauthor(s)NajiaHuda,MDAssistantProfessor,WayneStateUniversitySchoolofMedicineDirectorofMICU,DivisionofPulmonaryandCriticalCare,DetroitReceivingHospital

NajiaHuda,MDisamemberofthefollowingmedicalsocieties:AmericanCollegeofChestPhysicians,AmericanThoracicSociety,andSocietyofCriticalCareMedicine

Disclosure:Nothingtodisclose.

ChiefEditorMichaelRPinsky,MD,CM,Drhc,FCCP,MCCMProfessorofCriticalCareMedicine,Bioengineering,CardiovascularDisease,ClinicalandTranslationalScienceandAnesthesiology,ViceChairofAcademicAffairs,DepartmentofCriticalCareMedicine,UniversityofPittsburghMedicalCenter,UniversityofPittsburghSchoolofMedicine

MichaelRPinsky,MD,CM,Drhc,FCCP,MCCMisamemberofthefollowingmedicalsocieties:AmericanCollegeofChestPhysicians,AmericanCollegeofCriticalCareMedicine,AmericanHeartAssociation,AmericanThoracicSociety,AssociationofUniversityAnesthetists,EuropeanSocietyofIntensiveCareMedicine,ShockSociety,andSocietyofCriticalCareMedicine

Disclosure:LiDCOLtdHonorariaConsultingiNTELOMEDIntellectualpropertyrightsBoardmembershipEdwardsLifesciencesHonorariaConsultingMasimo,IncHonorariaBoardmembership

AdditionalContributorsRyanCChang,MDConsultingStaff,DepartmentofInternalMedicine,DivisionsofPulmonaryandCriticalCare,KaiserPermanenteSanFrancisco

RyanCChang,MDisamemberofthefollowingmedicalsocieties:AmericanCollegeofChestPhysiciansandAmericanThoracicSociety

Disclosure:Nothingtodisclose.

OlehWasylHnatiuk,MDProgramDirector,NationalCapitalConsortium,PulmonaryandCriticalCare,WalterReedArmyMedicalCenterAssociateProfessor,DepartmentofMedicine,UniformedServicesUniversityofHealthSciences

OlehWasylHnatiuk,MDisamemberofthefollowingmedicalsocieties:AmericanCollegeofChestPhysicians,AmericanCollegeofPhysicians,andAmericanThoracicSociety

Disclosure:Nothingtodisclose.

FranciscoTalavera,PharmD,PhDAdjunctAssistantProfessor,UniversityofNebraskaMedicalCenterCollegeofPharmacyEditorinChief,MedscapeDrugReference

Disclosure:MedscapeReferenceSalaryEmployment

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