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Ростовский Государственный Медицинский Университет

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 Nocturnal seizures (i.e., seizures that happen during sleep). There is no known, satisfying explanationforthisone.Wethinkofthisasariskforrecurrencebecauseseizuresthatoccurduring sleepstripawaymanyofthepotential“seizuremimics,”andthereforereflectactual,ongoingseizure activity.Forexample,nonepilepticseizures,vasovagalsyncope,andconvulsivesyncopearenotrisk factorsforseizurerecurrenceanddonotwakeapatientfromsleep.

Thus,ifapatientpresentswithasingleunprovokedseizureandhasanyofthethreeitemslistedabove —anabnormalEEG,arelevantbrainlesionidentifiedonimaging,oraseizureduringsleep—thatpatient canbediagnosedwithepilepsy.

First-TimeSeizure

Seizuresaccountforapproximately2%ofallEDvisits.Approximately25%ofthesewillbeforfirsttimeevents.Suchvisitscanbescary,bothforthepatientandforthehealthcareprovider,butthereisa simplealgorithmtohelpyoumanagethesepatients.

Startwiththebasics.First,takeagoodhistory.Thereareseveral“seizureriskfactor”questionsto askeverypatientwhopresentswithafirst-timeseizure,includingahistoryofdevelopmentaldelay, febrileseizuresduringinfancy,ahistoryofsignificantheadtraumawithlossofconsciousness,prior centralnervoussystem(CNS)infectionssuchasencephalitisormeningitis,andafamilyhistoryof seizures.

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Athoroughhistoryforseizureriskfactors,includingheadtrauma,isessentialwhenyouseeapatientfora first-timeseizure.

Next,performacompleteneurologicexamination.Patientsmaybeentirelybacktotheirbaselineor (asisoftenthecase)verysleepy,because:

1. theyarepostictal(thistermreferstothealteredstateofconsciousnessthatispresentimmediatelypost-seizure)and/or

2. theyhavebeengivenbenzodiazepinesbyEMSorEDproviderstotreattheseizure.

Althoughsleepinessisnotunexpected,focalityisaredflagthatshouldpromptconcernforan underlyingneurologiclesionsuchasanintracranialmassorbleed.Notethat,althoughthepostictalstate ismostoftenassociatedwithlethargyandconfusion,itcanbeassociatedwithagitationandpsychosisas well.

Checklabs.Youwantbasicstudies(includingaSTATfingerstickglucoseandametabolicpanel,as bothhypo-andhyperglycemiaandvariouselectrolyteabnormalitiescancauseseizures),aswellasa serumalcohollevelandurinetoxicologyscreen.Notably,iftheseizuresemiology4wasreportedtobe severalminutesofgeneralized,full-bodyshaking,youshouldnotbesurprisedtoseeamild-to-moderate leukocytosis,anelevatedcreatinekinase(CK),andanelevatedlactate;infact,ifyoudonotseethese things,youmaywanttodigabitdeeperintothehistoryandconsiderdiagnosesotherthanaseizure.

Finally,anoncontrastCToftheheadshouldalwaysbeperformedtoruleoutanyobviousunderlying pathology.

Atthispointyounowhavetwobigdecisionstomake:

1. Doesthepatientrequireadmission?If theaboveworkupisunrevealing(asitoftenis),theneurologicexaminationisnon-focal, and yourpatienthasreturned tohisorherclinicalbaseline,admissionisoftennotnecessary.Ifthelaboratoryworkorimagingisabnormal andrequiresfurtherevaluation,ifthepatientremainslethargicoragitatedforanextendedperiodoftime,oriftherearefocalneurologic abnormalitiesonexamination,thenadmissionisindicated.

2.  Should you start the patient on an antiepileptic medication? Immediate treatment with an antiepileptic drug (AED) has been shown toreducetheriskofseizurerecurrencewithinthe first2years followingthe initialeventbut has not been showntoimprove prognosis(definedassustainedseizureremission)inthelongterm.Further,asalreadydiscussed,theriskofseizurerecurrenceaftera single event is not that high. Thus, we need to weigh the benefits of starting an AED against the possible side effects and risks. Common practice is to defer AED initiationfollowinga first-time event, but there are three exceptions. You should recognize these fromthediscussionabove,andtheymakesense:thesearethefactorsthatsignificantlyincreasetheriskofseizurerecurrence.

a.

Nocturnalseizure

b.

Remote,symptomaticseizure(e.g.,ifthereisarelevantfindingonimaging,suchasencephalomalacia[softeningorlossofbrain tissue] from an old stroke or calcifications from prior neurocysticercosis; other lesions,such as a small arachnoidcystor an incidentallyfoundpituitarylesion,arelikelyincidentalanddonotwarrantAEDinitiation)

c.

AnabnormalEEG(thecaveathereisthatEEGsarenotroutinelyperformed inmostEDs; ifthepatient hasreturnedtohisor herbaseline,itisfinetodefertheEEGtotheoutpatientsetting).

Althoughthisalgorithmworksnearlyallofthetime,wewanttoemphasizethatthesedecisionsshould beindividualizedand,whenpossible,madeinconjunctionwiththepatient.Andthereareexceptions.Ifa patientworksinconstruction,forinstance,andspendshisorherdaysclimbingladders,itmaybe reasonabletostartanAEDatleasttemporarilytoavoidpotentiallysignificantinjuryshouldasecond

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seizureoccurwhileatwork.

Iftheplanisfordischarge,itisimperativetoensurecloseoutpatientfollow-up.AnEEGandMRIof thebrain(orderedwitha“seizureprotocol,”whichspecifiesthincutsthroughthetemporallobes;you’ll understandwhyshortly)shouldideallybescheduledpriortothefirstoutpatientvisitsotheresultscanbe reviewedandthepatientappropriatelytreatedatthattime.AnMRIofthebrainwithgadoliniumisoften indicatedifyoususpectneoplastic,infectious,orinflammatoryetiologies.

SeizureTypes

Whatexactlyisaseizure?Tobuildonthesimplifieddefinitionweusedatthebeginningofthischapter, wecansaythataseizureisasudden,paroxysmaleventcausedbysynchronoushyperactivityofneurons inthecerebralcortex(insimplerwords,awholebunchofneuronsinthebrainstartfiringprettymuchall atonce).Therearetwomaintypesofseizures,generalizedandfocal.

1.  Generalizedseizures. The onset of generalizedseizures involves both hemispheres of the brain simultaneously.There are several types.

a. Generalized tonic-clonic (GTC) seizures. Previously known as grand mal seizures, these are the most common type of

generalizedseizure.Theycanbebrokendownintofourphases:

i.

Theonset,classicallycharacterizedbytheabrup tloss of consciousness, oft enaccomp aniedbyaloud moan(alsoknownas an“ictalcry”due to strongmusclecontractionsthatrapidlypushairoutofthelungs).

ii.

Thetonic(stiffening) phase,during which the muscles of all four extremities,chest, andbackbecome st iff. This canlast any where from several secondstoapproximately1minute.

iii.

Theclonic (jerking)phase,duringwhichthereisgeneralized,rhythmic,nonsuppressiblejerking of allextremit ies.This t y p ically  lasts another 1 to 2minutes

iv.

Thepostictal period. Asmentionedearlier(seep age160),thisismost oft encharact erizedbysleepiness and confusionbutcanalsobeassociated withagit ationandpsy chosis.Thiscantakeanywherefromseveralminutestoseveralhourstofullyresolve.

Box6.1

Itisverycommonforpatients’fam ilymembers (oranyonewhowitnes sesageneralizedtonic-clonics eizure)toreportthattheepisode ofs hakingwentonfor 5,10,oreven20 m inutes .Mostoften,this is notbecaus ethepatientwasintruestatusepilepticus (see page

177),butbecaus ethefamilym embers werescaredandtheirsens eoftimebecameunders tandablydis torted.

1.

Duringtheseizure,familymembersorotherwitnessesshould:

2.

turnthepatientonhisor hersidetodecreasetheriskofaspiration;

3.

NOTstickaspoonoranythingelseinthepatient’smouth(thi sisnotonlyunhelpfulbutcanactuallybedangerous);

4.

timetheeventand,ifpossibl e,takeavi deo(thiscanbeextremelyhelpfuldiag nostical lyforthehealthcar epr oviderwhowilleventuallycareforthepatient);and

5.

call911ifthesei zurelastslong erthan5minutes,iftherearerecurr entseizureswi thoutreturntobaseline,ifthepatient’sskincolortur nsbl ue,orifther eisevidenceofseri ousheadi njuryorlacerati on.

b.

Tonicseizures:Theseconsistofabruptmusclestiffening,oftenassociatedwithlossofconsciousnessandfalling.

c.

Clonicseizures:Characterizedbyrepetitivejerkingmovementsusuallyinvolvingthefaceandarms.

d. Myoclonicseizures:Sudden,briefmusclecontractionsthatcanaffectanymusclegroup(mostoftenthearms);thesecanoccur

asasingleeventoraclusterofevents.Consciousnessisalmostalwayspreserved.

Box6.2Myoclonus

Myoclonus hasm anydifferentetiologies .Inthis chapter,wearetalkings pecificallyaboutepilepticmyoclonus ,m eaningm yoclonus that originatesfromabnormalepilepticactivityinthecerebralcortex.Physiologicmyoclonusisanormalphenom enonthatoccursinhealthy people:com mon examplesincludehypnicmyoclonus (those s uddenjerks  thatoccur whenyou’refallingasleep) and diaphragmatic myoclonus (hiccups!).Essentialm yoclonus ismyoclonusof no clear cause, oris  s uspected to be due togenetic caus es . For more details,seeChapter13.

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e.

Atonicseizures: Colloquiallyknown as “drop attacks,”theseareeffectivelytheoppositeoftonicseizuresin thattheycause a sudden loss ofmuscle toneresulting in abrupt collapsetothe ground. Patients whoexperience recurrentatonic seizures often needtowearhelmetstoprotectthemselves.

f.

Absenceseizures:Absenceseizuresare briefstaringspellstypicallylasting5to10seconds, accompaniedbybehavioralarrest andimpairedconsciousness.Theycanbeassociatedwithstereotypedautomatisms(repetitive,purposelessmovements)suchas eyelidfluttering,lip-smacking,orpickingatbuttons,andarealmostexclusivelyseeninchildren.

2. Focalseizures.Unlikegeneralizedseizures,whichbegininbothhemispheressimultaneously,theonsetoffocalseizuresislimitedtoa single, focal region of brain tissue. Although they begin this way, they can “secondarily generalize” such that the neuronal hyperexcitabilityspreadstoinvolvebothhemispheres;clinically,thepatientisobservedtoprogresstoageneralizedtonic-clonicseizure. Mostfirst-timeunprovokedseizuresinadultsarefocal-onsetseizuresthathavesecondarilygeneralized.

a.

 Focal Aware Seizures (FAS; previously called simple partial seizures). The patient is awake and aware that something abnormalishappening.Thesymptomsdependentirelyonthepartofthecortexthatisinvolved.Examplesincludeflashinglights (duetoinvolvementoftheoccipitalcortex)andrhythmic,jerkingmovementsofanarmorleg(duetoinvolvementofthemotor cortex).Whenthesemovementsbeginin onebodypart(let’s saythefingertips)andgraduallyspreadtoanother(upthe wrist andinto the arm), we callthis a“JacksonianMarch,” andit’s typicalfor thistypeofseizure. Youcanpicturethewaveof hyperexcitabilityspreadingupthehomunculusofthemotorcortex,causingthepropagationofthesesymptoms.

b.

FocalImpairedAwarenessSeizures(FIASs;previouslycalledcomplexpartial seizures).These arethemostcommontypeof seizures in adults with epilepsy. Patients will appear to be awake but are unresponsive and minimally reactive with their environment.Theymaystarestraightaheadordemonstrateautomatismssuchaschewingmovements,lipsmacking,grimacing, orwordrepetition.Thesetypicallylastseveralminutesandarefollowedbyapostictalperiod.Patientsaretypicallyamnesticfor theeventbutareoftenawareoftheirprecedingaura,ifoneexists(seeBox6.3).

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Youcanimagineafocalseizureaffectingthemotorcortexthatbeginsinthehandandthenspreads upwardintothearm.

Box6.3AbsenceSeizuresversusFocalSeizuresWithImpaired Awareness

Afterreadingthesedefinitions,itmayseemtrickytodistinguishbetweenabsenceseizures andfocalseizureswithimpairedawareness,butit’susuallyquitestraightforward.First, absenceseizuresarealmostexclusivelyseeninchildhood.Second,absenceseizuresare verybrief(lastingonlyseconds),neverbeginwithanaura,anddonothaveapostictal phase,whereasfocalseizureswithimpairedawarenessusuallypersistforseveralminutes, oftenbeginwithanaura,andaretypicallyfollowedbyapostictalphase.

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Box6.4Auras

Manypatientswilltellyouthattheyknowwhentheyareabouttoseize.Whattheyare describingaretheirauras,whicharerelativelybrief,focalseizuresthatoccurattheonsetof aseizureepisodeandaresubstantialenoughtocausesymptomsbutnotsolargeasto interferewithconsciousness.Commonexamplesincludea“rising”sensationinthestomach, ametallictasteinthemouthandpleasantorunpleasantsmells,butaurascanreallybejust aboutanything.Asuddensensationoffamiliarity(dejavu),unfamiliarity(jamaisvu), euphoria,orword-findingdifficultyareothercommonexamples.Visualaurasarealso common;thosethatoriginatefromtheoccipitallobeareun-formedelementaryhallucinations (thinkflashingwhiteorcoloredlights),whereasthosethatoriginatefromthetemporallobe canbemorecomplex(imagesofletters,animals,andevenpeople).

AQuickNoteontheDifferentialDiagnosisofSeizures

Asyounowknow,seizurescanpresentinmanydifferentwaysandcantherefore—attimes—bedifficult todiagnose.Twoofthemostcommon,andarguablythemostimportant,alternativediagnosestoconsider aresyncopeandstroke.

SeizureVersusSyncope

Syncopeisthelossofconsciousnessduetoasuddendropinbloodpressure.Itcanlookalotlikea seizure.Syncopeismostoftentheresultofanunderlyingcardiacorneurocardiogenic(vasovagal) etiology(seepage151),thetreatmentofwhichisdistinctlydifferentfromthemanagementofaseizure. Bothseizuresandsyncopecanbeassociatedwithlossofconsciousnessandincontinence.Convulsive syncope—acommonvariantofsyncopethatisassociatedwithbrieftonicormyoclonicactivity—can lookforalltheworldlikeaseizure.Sohowdowedistinguishbetweenthem?Certainfeaturescanhelp:

The period ofconfusionaftera seizurecanlastminutes tohours,whereas with syncopeitlastsat mostaminuteortwo. Whereas premonitory symptoms can occur with both, with syncope they tend to be cardiac (palpitations, diaphoresis, lightheadedness) or visual (tunnel vision, “blacking out”), and with seizuresaremoreoftenanaura(glitteringlights,afunnysmell,agastricrisingsensation,asenseof dejavu). Tonguebitingoccursalmostexclusivelywithseizures.

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Thedistinctionbetweensyncopeandaseizurecanbechallenging.

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SeizureVersusStroke.Thisone’salittleharder,butitcomesupallthetimeintheEDandcanbe challenging—sometimesevenimpossible—tosortout.

Let’sreturntoourpatientatthebeginningofthischapter,Carlton.HepresentedtotheEDwithaleft gazepreferenceandright-sidedweaknessafterbeingfounddowninaparkinglot,withseveralminutesof full-bodyshakingreportedbyabystander.Althoughtheshakingshouldabsolutelypromptyoutothinkhe hashadaseizure,thefirststepinhismanagementistoactivateastrokecode.Why?Carltonispresenting withtheacuteonsetoffocalneurologicdeficits(leftgazepreferenceandright-sidedweakness),sostroke (whichcanoccasionallypresentwithseizureatthetimeofonset)hastobeatthetopofyourdifferential because—asdiscussedinChapter2—strokesaretreatedinahighlytime-sensitivemanner.Sodo everythingyoucantofirstruleastrokeinorout,andthenconsidertherestofyourdifferential.

AcommonfeatureofseizuresthatcanbeconfusedwithstrokeisToddparalysis,atransientpostictal weaknessinvolvingthepartofthebodythatwasactivelyseizing.Let’sassumethatCarlton’sseizure beganinhisleftcerebralhemisphere(andthengeneralized,consistentwiththedescriptionoffull-body shaking).Hisrightarmandlegmusthavebeeninitiallyinvolved.Oncehestoppedactivelyseizing,he couldbedisproportionatelyweakontherightsideofhisbodyduetoToddparalysis,lastinganywhere fromminutestoseveralhours.Why?Theneuronsthatwerefiringawayarenowexhaustedandcantake sometimetorecover.Youcanimaginethatthiskindoffocalweaknesscaninitiallybedifficultifnot impossibletodistinguishfromweaknesscausedbyastroke.

Box6.5

ToddparalysisisnamedafterRobertBentleyTodd,anIrish-bornphysicianwhofirst describedthephenomenon.Hewasalsoknowntoprescribewineandbrandyforfevers,and someattributeoneofourbetter-knowncocktails—thehottoddy—tohimaswell.Whereas itsmedicinalvalueisdebatable,itmightbejustwhatyouneedtogetyouthroughtherestof thischapter!

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