Basics of Convulsive Disorders: Febrile Seizures

Abstract

Febrile seizure is the most common disorder faced in pediatric neurology. Two third of children with history of seizure have febrile seizure1. Lenox in 1949 wrote that febrile seizures may cause brain pathology with transient or permanent neurological deficit. In contrast Robinson in 1991 referred febrile seizures as having a “generally excellent prognosis”2. To make the diagnosis of febrile seizures, there must be documented fever and a clear cut history of convulsions. It is important to note that syncope in small in small childen may be precipitated by fever3. Therefore one must exam and investigate a child with fever carefully especially if it is the first febrile seizure.
A. Strong history of febrile seizures in siblings and parents suggest that it has a genetic predisposition. During past two decades the debate on febrile seizures has shifted from their natural history to their treatment.

Full text

Basics Of Convulsive Disorders:-
Febrile Seizures
Wajid Ali MD, Mushtaq A Bhat MD, Parvez Ahmad
MD, Javeed Iqbal MBBS
clinicalreview
Febrileseizureisthemostcommondisorderfacedin
pediatricneurology. Twothirdofchildrenwithhistoryofseizure
havefebrileseizure .Lenoxin1949wrotethatfebrileseizuresmay
causebrainpathologywithtransientorpermanentneurological
deficit.IncontrastRobinsonin1991referredfebrileseizuresas
havinga“generallyexcellentprognosis” . Tomakethediagnosisof
febrileseizures,theremustbedocumentedfeverandaclearcut
historyofconvulsions.Itisimportanttonotethatsyncopeinsmall
insmallchildenmaybeprecipitatedbyfever . Thereforeonemust
examandinvestigateachildwithfevercarefullyespeciallyifitis
thefirstfebrileseizure.
A.Stronghistoryoffebrileseizuresinsiblingsandparentssuggest
thatithasageneticpredisposition.Duringpasttwodecadesthe
debateonfebrileseizureshasshiftedfromtheirnaturalhistoryto
theirtreatment.
TheNationalInstituteofHealth(NIH)consensus
conference,hasdefinedfebrileconvulsionas“aneventthatoccurs
betweentheageof3monthsto3yearsandthatisassociatedwith
feverwithoutevidenceofintracranialinfectionorotherdefined
neurologicalcauseandwithoutahistoryofpreviousfebrile
seizures.”NIHhasnotgiventheprecisetemperatureatwhicha
seizureisconsideredfebrile cohortstudieshaveshownthatfebrile
seizuresisusuallyassociatedwithacoretemperaturethatrapidly
increasesto39oCorgreater . ThecommissiononEpidemiology
andprognosisoftheInternationalLeague AgainstEpilepsyhas
definedafebrileconvulsionas“anepilepticseizureoccurringin
childhoodafterageonemonth,associatedwithafebrileillness,not
causedbyaninfectionoftheCNS,withoutpreviousneonatal
seizuresorpreviousunprovokedseizureandnotmeetingthecriteria
foranotheracutesymptomaticseizures”
Nationalcollaborativeperinatalproject(NCCP)hassub-
classifiedfebrileseizuresintoSimplefebrileseizuresandComplex
febrileseizures.Complexfebrileseizureisone:-
a) whichlastsformorethan15minutes.
b) Whichrecurreswithin24hours.
c) Whichhasfocalfeatures.
d) Whichhasabnormalneurologicalsatus.
e) Withhistoryoffebrileseizuresinparentsorsibling.
Simplefebrileseizureisonewhichdoesnothavecomplexfeatures .
Between2and4%ofallchildrenhaveoneormore
febrileseizuresbytheageof5years.In AmericaNelsonand
Ellenbergreportedanincidenceof3.5%inwhiteand4.2%inblack
children.InJapantherateisreportedtobe9-10%. Thismaybedue
togeneticsusceptibility.Seizureisusuallyassociatedwithacore
temperaturethatrapidlyincreasesto39oCorgreater .
Nationalcollaborativeperinatalproject(NCCP)hassub-
classifiedfebrileseizuresintosimplefebrileseizuresandcomplex
febrileseizures.Overallprevalenceisabout4-5%. A higher
incidenceisnotedinboysascomparedtogirlsintheratioranging
from1.1:1to4:1.80%seizuresaregeneralizedandsimple. A
febrileseizurecanbepartialorgeneralizedtype.4%ofchildren
havefocalonsetand0.5%havefocaldeficit(Todds’ plasy). Tonic,
clonicevenatonicepisodesmaycharacterizefebrileseizures .18%
childrenhavecomplexseizuresin America,22%inBritainand
8.6%inScandinavia .Inanefforttopredictwhichchildisatarisk
offebrileseizures,fourriskfactorshavebeenidentified:-
1) Febrileseizuresinfirstorseconddegreerelative.
2) Neonataldischargeat28daysorlater.
3) Parentalreportofdevelopmentaldelay.
1
2
3
5
6.
5
1
DEFINITION
INCIDENCE ANDPREVALENCE
;
4) Daycareattendance.
Withtwooftheseriskfactors,theprobabilityofachild
developingfebrileseizuresisapproximately30%1.
A strongfamilyhistoryinparentsorsiblings
suggestsageneticbackground.Familystudieshaveshown
thatsimplefebrileseizuresmaybeinheritedasanantosomal
dominanttraitwithhighpenetrance .Geneoffebrileseizures
hasbeenmappedtochromosome19P and18Q13-21.Other
studieshaveshownthatepilepsywithfebrileseizuresisan
importantchildhoodgeneticepilepsysyndromewith
heterogenousphenotypes .
Theheightanddurationoffeverisimportantin
evaluatingfebrileseizuresbutrecordingthetemperatureisnot
usuallypossiblebecausetheseseizuresusuallyoccur
randomlyathome.
Viralinfectionscommonlycausethefeverleading
tofebrileseizures.SynthesisofimmunoglobulininCSFof
childrenwithfebrileseizureshasbeendemonstrated,
suggestingthatencephalitismaysometimesoccurandnot
recognized . Thereisanevidencethatexenthemsubtiumis
frequentlyaccompaniedwithfebrileseizures. AcuteHIV -6
infectionisacauseoffebrileseizures .Bacterialinfections
likeurinarytractinfections,shigella,otitismediaand
pneumocococalinfectionsareassociatedwithfebrile
seizures.Recentstudyhasshownincreasedriskoffebrile
seizuresonthedayofreceiptofDPT vaccineand8-14days
afterMMRvaccine,apparentlynotassociatedwithlongterm
adverseconsequences .
Approximately30-50%ofchildrenhaverecurrent
seizuresofthesehalfwillhavethreeand9%willhavemore
thanthree.Mostimportantriskfactorforrecurrenceistheage
ofonset.50%ofchildrenyoungerthan1yearexperience
recurrenceascomparedto28%ofchildrenwhodevelopfirst
febrileseizureafter1yearofage .Focal,prolongedor
complexeventsincreaserisksofarasrecurrenceisconcerned.
Riskfactorswhichpredictrecurrenceinclude:-
a) ahistoryoffebrileseizuresinfirstdegreerelative.
b) A seizureinducedbylowgradefever.
c) A briefdurationbetweentheonsetoffeverandthe
convulsion.
Althoughthechildrenwithsimplefebrileseizures
areatnogreaterriskoflaterepilepsythanthegeneral
population,somefactorsareassociatedwithincreasedrisk.
Theseinclude:
a) Presenceofatypicalfeatures.
b) Abnormalpostictalperiod.
c) Positivefamilyhistoryofepilepsy
d) Febrileseizuresbefore9monthsofage.
e) Delayeddevelopmentalmilestones.
f) Pre-existingneurologicaldisorder .
Thechancesofdevelopingepilepsyis90%when
severalriskfactorsarepresentascomparedtoincidenceof
1%inchildrenwhohavefebrileseizuresandnoriskfactors.
Theconsequencesoffebrileseizureson
developmentalmilestonesandbehaviorappeartobelimited.
Noresidualneurodeficitoccurseveninchildrenwhohad
convulsionslastingover30minutes.Studieshaveshownno
differencebetweencontrolsandchildrenwithfebrileseizures
inIQtestingandacademicperformance.Immediateshortterm
changeinbehaviorhasbeenreportedinupto35%children
afterfebrileconvulsionsbutlongtermfollowupshowsno
differenceinbehaviorinthesetwogroups. Therelationship
betweenfebrileseizuresandtemporallobeepilepsy(TLE)is
recognized.Controversyexistsastowhetherhippocampal
sclerosisof TLCisapreexistingcauseoraconsequenceof
AETIOLOGY
PRECIPITATING FACTORS
OUTCOME
10
11
12
13
1
5
.
JK-Practitioner Vol.13,No.3,July-September2006 161

febrileseizure.Betterneuroimagingtechniqueshaveshown
thatmesialtemporallesionof TLEexistedbeforetheonsetof
febrileseizures,sotheroleoffebrileseizuresasacauseof TLE
remainscontroversial . Twosynoumeshavebeenrecognizedto
beassociatedwithrecurrentfebrileconvulsions.
a) Hemiconvulsion,hemiplegia,epilepsy(HHE)
b) Progressivemyoclonicepilepsy(PME)ofchildhood.
InHHEanormallydevelopingchilddevelopsfebrile
statusepilepticuscharacterizedbyhemiconvulsionanda
persistantpostictaldeficit.HHEbeginsabruptlyandtriggering
causeisnotknown.Insomepatientscoagulationdefectswith
infectionisbelievedtobethecause.Inprogressivemyoclonic
epilepsyofchildhood,thechildpresentswithrecurrentfebrile
seizuresinfirstyearoflife. Theseseizuresareoftenlateralized.
Duringensuringmonthsprogressivedeclineincongnitiveskills
occur .
Thereisnoevidencethatfebrileseizuresare
associatedwithincreasedmortality .
Firstobjectiveistocontroltheconvulsions,thenthe
temperatureshouldbemeasuredtoconfirmthatthechildis
febrile.Itisimportanttodeterminewhetherornotthefever
precededtheconvulsion. Thehistoryandtheexaminationwill
providetheclueaboutthecauseoffever.
Febrileconvulsionusuallystopswithimmediate
intervention.Ifitdoesnotthechildeshouldbeadmittedto
hospitalfollowingfactorsfavouradmissionafterfirst
convulsion.
a) Complexconvulsion
b) Childagedlessthan18months
c) Reviewbydoctorathomenotpossible.
d) Unusualparentalanxiety.
Investigationsusuallyarenotneededinfebrile
seizures:-Investigationsareneededtofindoutcauseoffever.
Themostimportantaspectofdiagnosisistoruleout
anunderlyinginfectionofthecentralnervoussystem.Clinical
signswillclearthediagnosisofmeningitisandencephalitisin
mostofthecases.Howeverinchildrenlessthan18monthsof
age,thesesignscanbesubtleorabsent. Thedecisiontoperform
lumbarpunctureinsuchcasesiscriticalone.Recommendations
todolumberpunctureinfirstfebrileconvulsionsare:
-Iftherearesignsofmeningismus
-Iftheconvulsionsarecomplex.
-Ifchildisundulydrowsy,irritableorsystemicallyill.
-Ifthechildislessthan18monthsold(Probably)andalmost
certainlyifthechildisagedlessthan12months.
Doctorshouldreassessthechildagainafterfewhourstoassess
thedecisionofnotperforminglumbarpunctureiscorrect.One
shouldneverassumethatachildwithpreviousfebrileseizure
willnotdevelopmeningitisandoneshouldalwaysobserve
childrenwithpersistentfevereveniftheinitiallumbarpuncture
isnegative.ChildrenwithinitialnormalLumbarpuncturemay
laterdevelopbacterialmeningitis .
ThevalueoftheEEGinevaluationoffebrileseizures
hasbeendisappointing.Itisabnormalearlyonin2/3 of
affectedchildren.Bothfocalandgeneralizedabnormalitieshave
beendescribedinimmediateportictalperiodbutthese
abnormalitiesarenotpredictiveofeithertheriskofarecurrence
ortheriskoflongtermepilepsy .
ReportedabnormalitiesofEEGinclude:
1) Focalslowingmainlyoveroccipitalregions
(5%).
2) Focalsharpwaves,mainlytemporooccipital
region(3%).
3) focalormultifocalspikes(1.6%).
4) Hypnologicbursts.
5) Generalizedspikedischarge.
EEGisrecommendedonlytoruleoutencephalitic
processinachildwithcomplexfebrileseizuresorabnormalpost
ictalcourse.NoroutineEEGisrecommendedforsimplefebrile
seizures .
:
Mostofthefebrileseizuresstoptillthepatientis
broughttohospital.Inrareinstancesthechildcontinuestohave
aseizureuponarrivalatthehospitalorhasaprolonged
recurrenceinhospital.Insuchcasesactualtreatmentmaybe
initiated.Diazepam0.5mgto1mgperkgisgivenparentrally.
Rectaldiazepam.5mg/kgandrectalLorazepam0.1mg/kgalso
stopsanattack.Fevershouldbecontrolledbyacetaminophen
1.5mg/kg/dosetobegivenevery4-6hourswhenrectal
temperatureexceeds37.9oC.Ifthechildisvomiting
acetaminophencanbegivenrectally.Iffeverdoesnotcome
downibuprofen5mg/kg/dosewithacetamophen10mg/kg/dose
canbegiven. Thiscombinationreducesfeverthereissignificant
seizurereduction.Studieshaveshownthatacetaminophenis
moreeffectiveincontrollingfeverthanthephysicalmethods
suchasfanning,coldbathingandtepidsponging .
a) Intermittentprophylaxis
b) Continuousprophylaxis
:
Intermittentprophylacticoralorrectaldiazepam
reducesthenumberofrecurrencesinfebrileseizures.Diazepam
preventsseizureswhengivenattheonsetoffever.
Phenobarbitoneisneededinlargedoseanditseffectiveblood
concentrationreachesin90minutessoitisnotrecommended.
Oraldiazepamof1mg/Kg/dayor0.3mg/kg/doseq8hourlyis
veryeffectiveinreducingtherecurrence.Itcanbecontinuedfor
2-3days.Sideeffectsofdiazepamincludeataxia(30.0%)
lethargy28.8%andirritability24.2%15.
c) :
Phenobarbitoneatadoseof4-5mg/kg/dayreducesthe
numberofrecurrencesinfebrileconvulsionsandcauses:
behavioralsideeffectandcognitivedysfunctionandisnot
recommended.Sodiumvalproatehasalsoshowntoreducethe
recurrenceratebutthepotentialrisksofdrugdonotjustifyits
useinadisorderwithanexcellentprognosis.Despiteevidence
thatthedrugscanreducetherecurrence,therearegood
argumentsthatprophylacticmedicationisrarelyindicated.
Recentstudyhasshownthatoverallcontinuousprophylaxiswith
Phenobarbitoneorvalproatedidnotlessentheriskofrecurrence
infebrileconvulsionssothesedrugsarenotrecommended.
Febrileseizuresarecommonandbenigndisorder.
Majorityofthechildrenhaveoneattackinlifetimeand
subsequentlyhavenormalintellectualbehaviorandneurological
function.Inmorethan80%ofchildrenfebrileseizurespresent
theexpressionofageneticallyinheritedresponsetofever.For
thesechildrennotreatmentisrequiredandparentsshouldbe
reassured.Rarelyfebrileseizuresrepresentlittleevidencefor
laterepilepsy.Lumbarpunctureisnotroutinelyrecommended
excepttoruleoutCNSinfectionandinchildrenyoungerthan18
months.EEGisnotpredictiveoflaterepilepsyinchildrenwith
febrileseizures.Diazepamgivenintermittentlyinpatientsof
febrileseizuresreducesthechancesofrecurrence.Rarelyshould
dailyprophylacticanticonvulsanttherapybeconsideredforuse
inchildrenwithfebrileconvulsions.
Deptt.OfNeonatology,SKIMSSoura,Srinagar
Dr. Wajid Ali
AdditionalProfessor,Deptt.OfNeonatology,SKIMSSoura,
14
14
rd
1
1
15
MANAGEMENT
ADMISSION TOHOSPITAL:
INVESTIGATIONS:
LUMBARPUNCTURE:
ELECTROENCEPHALOGRAM(EEG)
TREATMENT OF THE ACUTE ATTACK
PROPHYLACTIC TREATMENT
CONCLUSION:
:
:
Authors’ affiliations:
Correspondence
INTERMITTENT PROPHYLAXIS
CONTINUOUSPROPHYLAXIS
JK-Practitioner2006;13(3):161-163
clinicalreview
JK-Practitioner Vol.13,No.3,July-September2006
162

1. Lionel Ca rma nt: Current Managemen t of Ch ildhood
Neurology.Parther Publishers Ltd., 1999; pp.120-124.
2. Robinson, R.J. Febrile Convulsions further reassuring news
about prognosis. Br. Med. J. 1991; 33,1345-1346.
3. StevensinJBP, fits and faints Oxford: Mac Keith Press, 1990.
4. Nelson KB, Ellenberg JH. Prognosis in children with febrile
seizures. Perdiatrics 1978; 61: 720-727.
5. Robert H.A. Haslam. Nelson’s Text book of Pediatrics. 17
edition W.B. Saunders 2004; P.P1994-1995.
6. Commission on Epidemiology and Prognosis, Internatiuonal
League Against Epilepsy Guidelines for epidemiologic studies
on epilepsy Epilepsia, 1993, 34, 592-596.
7. Nelson KB; Ellenberg J H. Predictors of epilepsy in children
who have experienced febrile Seizures. New England Journal
of Med. 1976, 295, 1029-1033.
8. Forsgren L, Sidenvall R; An incident case referent study of
febrile convulsions in Children: genetic and social aspects.
Neuropaediatrics 1990, 21, 153-159.
9. Nabbout R, Prud Homme JF; A locus for pure simple seizures
maps to chromosome 6 q 22- q 24. Brain, 2002, 125, 2668-2680.
10. Wallace R, Scheffer IE; Generalised epilepsy with febrile
seizures plus: Mutation of sodium channel subunit SCN 1 B.
2002.
11. Wallace, S. J. The Child with febrile seizures. John Wright,
London 1988.
12. Koudo K, Nagafuji H. Associaiton of Human Herpes virus 6
infection of the Central Nervous System with recurrence of
febrile convulsions. J. Infect. Diseases 1993, 167, 1197-1198.
13. Hirtz DG, Nelson KB. Seizures following childhood
immunizations. Paediatrics 1983, 102, 14-18.
14. Nelson KB et al, Prognosis in children with febrile seizures.
Pediatrics 1978, 61, 720-727.
15. Joint Working Group of the Research Unit of Royal College of
Physician and the British Ped. Association. Guidelines for
management of convulsing with fever. B.M. J. 1991, 303, 634-
636.
References:
JK-Practitioner Vol.13,No.3,July-September2006 163
clinicalreview