DiagnosticApproachtoAlteredMentalStatusMichelStatler,MLA,PACTuesday,May26,2009

I. LearningObjectivesa. Interprettheabnormalitiesonphysicalexamfoundinapatientwithalteredmental

status.b. Recognizethesignsandsymptomsassociatedwithimpendingherniation.c. Selecttheappropriatediagnosticstudiestoevaluateapatientwithalteredmental

status.

II. Introductiona. Consciousnessisthestateofawarenessofselfandtheenvironment

i. Normalconsciousnessdependentupon:1. Intactcerebralhemispheresforcognition2. Reticularformationforalertness

b. Alteredmentalstatusresultsfromanimpairmentofarousalorcognitionc. Disordersofconsciousnesscanseeacuteconfusionalstatesordeliriumd. Disordersofcognitionleadtoimpairmentofmemoryorothercognitivefunction(i.e.

judgmentorabstractthinking)i. Dementiaaffectscognitionwithoutaffectingconsciousnessii. Focalneurologicdiseasecanaffectcognitionifcriticalcorticalareasofcognition

areinvolved.e. Comaduetodysfunctionofbothcerebralhemispheresand/ortheupperbrainstem

III. Etiologies

a. Metaboliccausesi. Hypoxiaii. Electrolyteand/orglucosedisturbancesiii. Uremiaiv. Hepaticfailurev. Drugssedatives,opiates,antidepressants,anticonvulsantsvi. Toxinsalcohol,carbonmonoxide,heavymetalsvii. Psychiatricdisorders

b. Intracranial/structuralcausesi. Traumadiffuseaxonalinjury,epiduralorsubduralhematomaii. Vascularischemicstrokewithmasseffect,brainstemstroke,hemorrhagic

strokeiii. Infectionmeningitis,encephalitis,abscessiv. Otherepilepsy,hydrocephalus

IV. ImportantHistoricalDetails

a. Dependentupontheobservationsofothersi. Onset/timelineofsymptomsii. Historyofrecentsystemicorneurologicsymptomsiii. Historyofheadtraumaiv. Pastmedicalhistoryrenalorhepaticdisease,diabetesv. Medications

vi. Druguse,includingalcoholvii. Associatedsymptoms:fever,HA,stiffneck,seizureactivity

b. Historywithpossibleetiologiesi. Hxofheadachemeningitis,encephalitis,subarachnoidhemorrhage,

intracerebralhemorrhageii. Hxofpriorheadinjurychronicsubduralhematomaiii. Acuteonsetofsymptomsischemicorhemorrhagestrokeiv. Gradualonsetofsymptomsmasslesionormetaboliccausev. Hxoflimbtwitchingand/orincontinenceseizurewithpostictalconfusionvi. Hxofdiabeteshypoglycemiavii. Hxofmalignancyintracranialmetastasis

Case#1A73yearoldrighthandedmanisbroughtinbyhissonforincreasingforgetfulness.Hissonsaysthatheoftenlosesthingsandishavingahardtimerememberingdatesandfindingtherightwordsforthings.Recentlyhehasbeendroppinghiscoffeecupandhastroublefeedinghimselfandwriting.Alertandorientedx2;unabletorecalldate.Wordfindingdifficulty;abletoname3/5objects.Poorrecallatoneminute(1/3);cannotrecallnamesofpresidents;knowsdate/placeofbirth.Unabletodoserial7sorrepeatdigitspan.Abletowrinkleforeheadbilaterally,mildflatteningofthenasolabialfoldontheleftDecreasedhandgriponleft,4/5weaknessleftUE.

V. PhysicalExama. Vitalsigns

i. Signsofinfectionorsepsisii. Respiratorypatterns

1. CheyneStokesrespirationsseenwithbihemisphericlesionsormetabolicencephalopathy

2. Centralneurogenichyperventilation(Kussmauls)seenwithmetabolicacidosisorherniation

3. Apneusticrespirationsseenwithpontinedamage4. Clusterbreathingseenwithpontineorcerebellardamage5. Ataxic(Biots)respirationsseenwithmedullarydamage

iii. Hypertensionwithbradycardiaassociatedwithhighintracranialpressureb. HEENTlookforsignsoftrauma

i. BattlesorRaccoonsignii. CSFotorrheaorrhinorrheaiii. Hemotympanum

c. Skinexamcherryredskinconsistentwithcarbonmonoxidepoisoningd. Neurologicexam

i. Levelofconsciousness1. Lethargicpatientmaybeconversantbutinattentiveandslowto

respond;cantperformsimpletaskslikecounting.2. Stuporincompletearousaltopainfulstimuli;little,ifanyresponseto

verbalcommands3. Comatoseunresponsivetoallstimuli

4. Ifpatientresponsive,attempttoevaluatelanguage,memoryandconcentration

5. Folsteinminimentalstatusexamcanbeusedii. GlasgowComaScale15pointscaleusedtopredictmortality

1. Basedoneyeopening,motor,andverbalresponsesa. Decorticateposturingflexionandadductionofarmsand

extensionoflegs(flexorresponse)i. Reflectslesionincorticospinaltractfromcortexto

uppermidbrainb. Decerebrateposturingextension,adduction,andinternal

rotationofthearmsandextensionofthelegs(extensorresponse)

i. Reflectsdamagetocorticospinaltractatlevelofpoonsoruppermedulla

iii. AVPUalternateassessmenttool;usedprimarilybyEMS1. Alertness2. Verbalresponse3. Painfulstimulus4. Unresponsive

iv. RestingeyepositionGazepreference1. GazepreferenceAWAYfromthesideofthehemiparesisisconsistent

withalargecerebralhemisphericlesiona. Frontaleyefieldsnormallymoveeyestocontralateralsideb. Iflesionpresenteyeslookatthelesionandawayfrom

hemiparesis2. GazepreferenceTOWARDthesideofthehemiparesisisconsistentwith

alesioninthebrainstem(pons)a. Lateralgazemechanismintheponsmovestheeyestothe

ipsilateralsideb. Iflesionpresent,eyesdeviateawayfromthedamagedsideand

towardthehemiparesisv. Spontaneouseyemovement

1. Rovingeyemovementsa. Slow,conjugatehorizontalmovementsb. Indicatesbrainstemcontrolofeyemovementsisintactc. Seenwithbilateralhemisphericdysfunction(ieanoxia)

2. Ocularbobbinga. Downwardjerkingofbotheyesfollowedbyslowreturntomid

positionb. Seenwithpontinelesions;needtoruleoutlockedinstate

vi. Reflexeyemovements1. Oculocephalic(DollsEyes)2. Oculovestibular(Calorics)

vii. LockedInSyndrome1. Patientawakebutquadriplegicwithparalysisofhorizontaleye

movements2. Verticaleyemovementpreserved3. Abletocommunicatebylookingdownorblinking

4. Associatedwithlargepontinelesion,ieaninfarctorhemorrhage5. Prognosisfavorable;recoverypossible

viii. Pupillaryresponses1. Midposition(25mm)andnonreactiveseenwithmidbrainlesions2. Pinpoint&reactiveseenwithpontinelesions3. Unilateraldilated&fixedseenwithaCNIIIlesion/uncalherniation4. Bilateraldilated&fixedseenwithcentralherniation,hypoxia

ix. Fundoscopicexamlookforpapilledema1. Usuallytakes12hoursbeforepapilledemapresent

x. MotorExamlookforspontaneousmovementsandpresenceoffocaldeficits(leftvs.right;uppervs.lowerextremity)

1. Usepronatordrifttoassessforsubtleweaknessesxi. CheckDTRs.corticallesionswillproducehyperactivereflexes,clonus,anda

positiveBabinskixii. Foradditionalcomponentsoftheneurologicexamtobereliable,youneedan

alertandcooperativepatient(i.e.sensoryandcerebellarexams,meningealsigns)

e. PsychogenicComadiagnosisofexclusioni. Patientsarephysiologicallyawakebutunresponsiveii. Suspectwheninconsistentexamfindingsiii. Pupillaryandoculovestibularreflexesareintactiv. EEGisnormal

Case#2A24yearoldWMsustainedaclosedheadinjuryinaMVC.TherewasabriefLOCatthescene,butthepatientwasawakeuponarrivaltotheED.Hewasorientedtonamebutnottoplaceortime.Hecouldmoveallfourextremitiesuponcommand.Pupilswereequal,roundandreactivetolight.12hourslater,hewasunresponsivetoverbalcommandsandwithdrewtopainfulstimuli.Therightpupilwas6mmandsluggishlyreactive;leftpupilwas3mmandbrisklyreactive.

VI. ImpendingHerniationa. Potentiallylifethreateningcomplicationthatcanbeenseenwithamasslesion,

traumaticinjury,orCNSinfectionb. Increasingunresponsivenesstostimulic. Changesinpupillaryresponsesd. Unilateralfixedanddilatedpupilsareconsistentwithuncalherniatione. Changesinrespiratorypatterns

i. CheyneStokes,apneustic,orclusterrespirationsf. Changesinmotorexam(withdrawingtopain,posturing)

VII. DiagnosticEvaluationa. ThebasicsABCsb. Intubateifpatienthasrespiratorycompromiseordeeplycomatosec. StartanIVd. Insertfoleycathetere. Checklabs:CBC,comprehensivemetabolicpanel,arterialbloodgas,PT/PTT,urinalysis,

fingerstickglucose,toxicologyscreen/bloodalcohollevel

f. Mayalsogetthyroidfunctiontests,serumcortisol,andammonialevelg. NeuroimagingCT/MRI

i. NoncontrastCTgeneralfirstlineii. Includecontrastiftumororabscesssuspected

h. LumbarpuncturewithCSFanalysisruleoutCNSinfectionorsubarachnoidhemorrhage

i. EEGifdiagnosisunclear,EEGcanruleoutpostictalstate,nonconvulsivestatusepilepticus,ormetaboliccause

VIII. Puttingitalltogether

a. Patientwithnonfocalexamandintactbrainstemreflexes:i. Characterizedbyreactivepupils,fulleyemovementsandsymmetricmotor

responsesii. Mostlikelyetiologytoxic/metaboliccause,CNSinfectionorhydrocephalus

b. Patientwithfocalhemisphericsignsi. Characterizedbycontralateralhemiparesis,gazeparesisii. Mostlikelyetiologystructurallesion

1. Forexamplestroke,tumor,orsubduralhematomac. Patientwithfocalbrainstemsigns

i. Characterizedbyabnormalpupillaryresponses,cranialnervepalsies,orposturingonmotorexam

ii. Mostlikelycausebrainstemlesion(strokeortumor)oramasslesionwithherniation

IX. PearlsofPractice

a. StructuralcausesofAMSareassociatedwithfocaldeficitsonexamb. Focalfindingsonexamareanindicationforneuroimaging

i. CTgoodfortrauma&acutecerebralischemiaii. MRIgoodfortumorsorotherstructuralabnormalities

c. Bemindfulofchangesconsistentwithimpendingherniationobtainanemergentneurosurgicalconsultation

X. References

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