Do pets reduce the likelihood of sudden unexplained death in epilepsy?

Short

communication

Do

pets

reduce

the

likelihood

of

sudden

unexplained

death

in

epilepsy?

Vera

C.

Terra

,

Ame´rico

C.

Sakamoto

,

He´lio

R.

Machado

,

Luciana

D.

Martins

,

Esper

A.

Cavalheiro

,

Ricardo

M.

Arida

,

Claudia

Sto¨llberger

,

Josef

Finsterer

*

,

Fulvio

A.

Scorza

a_{CentrodeCirurgiadeEpilepsia(CIREP),DepartamentodeNeurocieˆnciaseCieˆnciasdoComportamento,FaculdadedeMedicinadeRibeira˜oPreto,UniversidadedeSa˜oPaulo,Ribeira˜o}

Preto,Sa˜oPaulo,Brazil

b_{DisciplinadeNeurologiaExperimental,UniversidadeFederaldeSa˜oPaulo/EscolaPaulistadeMedicina(UNIFESP/EPM),Sa˜oPaulo,Brazil} c_{DepartamentodeFisiologia,UniversidadeFederaldeSa˜oPaulo/EscolaPaulistadeMedicina(UNIFESP/EPM),Sa˜oPaulo,Brazil} d_{KrankenanstaltRudolfstiftung,Vienna,Austria}

1. Introduction

Suddenunexpecteddeath in epilepsy(SUDEP) is one of the mostimportantepilepsy-relatedmodesofdeathinpatientswith long-standing uncontrolled epilepsy. The pathomechanism of SUDEPisunknown.ProbablepredisposingfactorsforSUDEPare long-standing epilepsy, the genetic background, antiepileptic drugs, coldtemperatures, or unknownfactorsthat transform a seizureintoafatalevent,likelackofsupervision.7,10_Strategiesto

prevent SUDEP comprise pharmacological measures, surgery, cardiac and respiratory interventionsbut their benefit hasnot beenestablishedyet.10

Thereareindicationsthatepilepsypatientswholivetogether withadoghaveabetterqualityoflife,lowerseizurefrequency, andabetterglobaloutcomethanepilepsypatientswithoutpets.4,9

Inthelightoftheuncertaintiesaboutthepathogenesisandrisk factorsforSUDEP,itwouldbeinterestingtoknowifpatientswith epilepsy who live together with dogs develop SUDEP less

frequentlythanepilepsypatientswithoutdogs.Aimofthepresent studywastoassesstherelationshipbetweenthepresenceofpets in homes of epilepsy patients and the occurrenceof SUDEP in childrenandadolescentswithepilepsyinalargeepilepsyunitover a10-yearperiod.

2. Methods

To examine the potentially beneficial role of pets for the occurrenceofSUDEPwereviewedchildrenandadolescentswith SUDEPofourepilepsyunitovera10-yearperiod(2000–2009).A conversational interview with parents or relatives of SUDEP patientswascarriedoutinJuly2009toinvestigateifthepatient livedtogetherwithanydomesticpet(suchasdogs,cats,andbirds) at the time of death or not. The 1081 patients who did not experienceSUDEPservedasacontrolgroup.

Includedwereallepilepsypatients,agedzeroto18years,of the Clinical Hospital of Ribeira˜o Preto who died from SUDEP between January 2000 and June 2009. The Ribeira˜o Preto epilepsy center is a tertiary referral center in Brazil that provides services for pediatric patients from all over the country. The history of 1092 patients was retrospectively reviewed for the occurrence or absence of SUDEP. For the Seizure21(2012)649–651

ARTICLE INFO

Articlehistory: Received20June2012

Receivedinrevisedform22June2012 Accepted23June2012

Keywords: Epilepsy Suddendeath Companionanimals Petownership

ABSTRACT

Purpose:Toassesstherelationshipbetweenthepresenceofpetsinhomesofepilepsypatientsandthe occurrenceofsuddenunexpecteddeathinepilepsy(SUDEP).

Methods: ParentsorrelativesofSUDEPpatientscollectedoveraten-yearperiod(2000–2009)inalarge epilepsyunitwereaskedifthepatientlivedtogetherwithanydomesticpetatthetimeofdeathornot. PatientswhodidnotexperienceSUDEPservedascontrols.

Results andconclusions: Elevenoutof the1092includedpatients(1%)experiencedSUDEP,allwith refractorysymptomaticepilepsy,butnoneofthemhadpetsintheirhomesatthetimeofdeath.In contrast,thefrequencyofpet-ownershipinthecontrolgroup(n=1081)was61%.Accordingtoprevious studiestherearesomeindicationsthathumanhealthisdirectlyrelatedtocompanionshipwithanimals inawaythatdomesticanimalspreventillnessandfacilitaterecoveryofpatients.Companionanimalscan bufferreactivityagainstacutestress,diminishstressperceptionandimprovephysicalhealth.These factorsmayreducecardiacarrhythmiasandseizurefrequency,factorsrelatedtoSUDEP.Companion animalsmayhaveapositiveeffectonwell-being,thusimprovingepilepsyoutcome.

ß_{2012BritishEpilepsyAssociation.PublishedbyElsevierLtd.Allrightsreserved.}

*Correspondingauthorat:Postfach20,1180Vienna,Austria. Tel.:+4317116592085;fax:+4314781711.

E-mailaddress:fifigs1@yahoo.de(J.Finsterer).

ContentslistsavailableatSciVerseScienceDirect

Seizure

j o urn a lhom e pa g e :ww w . e l se v i e r. c om / l oca t e / y se i z

retrospective analysis demographic and clinical data (age at onset of epilepsy, epilepsy syndrome, seizure frequency, antiepilepticdrug(AED)therapy,courseofneurological abnor-malities,electroencephalographic(EEG)findings,neuroimaging findings,presenceorabsenceofpetsinhomesofpatients)were collected. Excluded were cases in which the diagnosis of epilepsywasuncertain.Familieswerecontactedforelucidation ofthecauseofdeath,andautopsiesthathadbeenaccomplished were revised. The etiology of epilepsy was classified as symptomaticincaseofknowncauseoftheseizure,cryptogenic in case the etiology was unknown, and as idiopathic in case clinicalandEEGfindings wereclearly relatedto anidiopathic syndromebutthechilddidnotpresentanydevelopmentaldelay orassociatedneurological condition.Patients withexclusively febrileseizuresorasingleseizurewereexcludedfromthestudy. ‘‘Definite’’SUDEPwasdiagnosedaccordingtopublishedcriteria ifa childwith epilepsyandrecurrent unprovokedseizuresdied unexpectedlywhileinareasonablestateofhealth,ifdeathoccurred suddenlyduringnormalactivitiesin benigncircumstances,ifno obviousmedicalcauseofdeathcouldbeidentified,orifdeathwas notdirectlycausedbyanepilepticstate. SUDEPwasconsidered ‘‘probable’’incaseallabove-mentionedcriteriawerepresent,but post-mortem data were not available. SUDEP was considered ‘‘possible’’whenconclusiveandpost-mortemdatawerelacking.6

3. Results

SUDEPwasdiagnosedin11ofthe1092patientsincludedinthis study(1.01%).Clinicalanddemographicdetailsofthese11patients arepresentedinTable1.All11SUDEPpatientshadsymptomatic epilepsy(67%focal,33%generalized)(Table1).Almostallpatients had at least monthly seizures (81% of the cases) (Table 1). Accordingtotheirrelatives,noneofthepatientshadpetsathome atthetimeofdeathorduringtheyearspriortoSUDEP.Amongthe 1092 included patients, 665 (60%) had a pet in their family. Excludingthe11patientswithSUDEP,whodidnothaveapet,the frequencyofpetsinthecontrolgroupwas61%.

4. Discussion

ThisstudyinchildrenandadolescentswithSUDEPshowsthat petswereabsentinallhouseholdsorpublicsurroundingswhen SUDEPoccurred.Incontrast,thefrequencyofpetsamongthose whodidnotexperienceSUDEPwashigh.Whetherthepresenceof petsatthetimeofthecriticaldeteriorationofhealthwouldhave preventedthefataloutcomeremainsspeculative.

Generally, there is increasing evidence that dogs have a beneficialeffect ontheirowners’healthbyenhancingphysical activity, social contacts, or by providing an anti-depressive effect.5 _{Additionally,service dogshavea positive influenceon}

the well-being, self-esteem, and community integration of people with disabilities.1,2 _{Dogs may be preventive against}

SUDEPbyreducingstressandsympatheticresponses.1_Stressisa

majorriskfactorforsuddencardiacdeathsuggestingthatstress mayalsoplaya pathogeneticroleinSUDEP.Stress inepilepsy patients may originate from insufficient seizure control, emotional stressrelatedto seizurefrequency, deprivation and stigmatization by the disease, AEDs or other drugs known to increase the sympathetic tone, or from uncertainties about futureperspectives.Furthermore,dogsarereportedtoreactto medical emergencies of their owners like hypoglycemia, ventricular fibrillation, or subarachnoid hemorrhage.12 _{It has}

beenalsoreportedthatdogsareabletoanticipateseizuresofthe ownersandtoreacttoseizuresbysearchingforhelp.4,9_Though

various speculations have been raised to explain SUDEP, its pathogenetic background remainselusive.11 _Apossible

patho-mechanismtoexplainSUDEPis thedevelopmentofa seizure-triggeredTakotsubo-syndrome.3_{Absenceofpetsatthetimeof}

SUDEPinanyoftheincludedpatientscouldbeexplainedbythe fact thatthe riskof SUDEPis highest in patients with severe epilepsy not controlled by two or more AEDs or a low IQ,13

which may limit the ability of persons at risk for SUDEP to havepets.

Limitationsofthestudywerethatithadaretrospectivedesign, thatitwasnotassessedifthe11SUDEPpatientslivedinasingle individual household or together with others, that potential cardiacorpulmonaryriskfactorsforSUDEPwerenotreviewed, andthatstresswasnotquantified.

Inconclusion, pet-ownership is infrequentin SUDEP cases, and living without a pet could be a potential risk factor for SUDEP.There is aneed tore-evaluatealready published case-control studies with respect to pet-ownership.8,10 The higher frequency of pet-owners in controls compared to SUDEP patients supports a possible protective role of pets against SUDEP. A lower prevalence of SUDEP in pet-owners with epilepsy living in single individual households than in non-pet-owners living in single individual households would emphasize that pets play a beneficial role as supervisors of epilepsypatients.

WeconfirmthatwehavereadtheJournal’spositiononissues involved in ethical publication and affirm that this report is consistentwiththoseguidelines.

Table1

DemographicdatafrompatientswhodiedofSUDEP.

Patient Sex Ageatonset ofepilepsy

MRI EEGabnormalities Epilepsy syndrome

Ageat death(years)

Seizure frequency

Conditionofdeath

1 F 1 Demyelination Unspecific

findings

FSE 11 Two/week Inbed,duringsleep

2 F 2 Porencephaly Focal FSE 8 Daily Cardiacarrest

3 F 0.8 Normal Multifocal FSE 3 2/year Inbed,duringsleep

4 F 0 Atrophy Multifocal FSE 2 4/year Inbed,duringsleep

5 M 0.6 Normal Generalized GSE 2 3/week Inbed,duringsleep

6 M 0.7 Normal Focal FSE 9 Daily Inbed,duringsleep

7 M 0.6 Normal Multifocal FSE 11 Daily Inbed,duringsleep

8 F 1.6 - Multifocal FSE 3 Daily Inbed,duringsleep

9 M 0.5 Atrophy Normal FSE 9 1/week Cardiacarrest

10 M 2 Mesiotempporal

sclerosis

Multifocal FSE 16 1/week Instreet,duringa

seizure

11 M 1.6

Normal Focal FSE 18 3/week Instreet,

duringaseizure

M:male;F:female;FSE:focalsymptomaticepilepsy;GSE:generalizedsymptomaticepilepsy.

Conflictofinterest

Noneoftheauthorshasanyconflictofinteresttodisclose.

Acknowledgements

FAPESP,CInAPCe-FAPESP,CNPqandINCT/MCTforsupporting ourstudies.

References

1.AllenK,BlascovichJ,MendesWB.Cardiovascularreactivityandthepresenceof pets,friends,andspouses:thetruthaboutcatsanddogs.Psychosomatic Medi-cine2002;64_:727–39.

2.AllenK,BlascovichJ.Thevalueofservicedogsforpeoplewithsevere ambula-torydisabilities.Arandomizedcontrolledtrial.JournaloftheAmericanMedical Association1996;275:1001–6.

3.FinstererJ,Sto¨llbergerC. Cardiopulmonarysurveillanceto preventSUDEP. LancetNeurology2009;8:131–2.

4.KirtonA,WirrellE,ZhangJ,HamiwkaL.Seizure-alertingand-response beha-viorsindogslivingwithepilepticchildren.Neurology2004;62:2303–5.

5.McNicholas J, GilbeyA,Rennie A,AhmedzaiS, DonoJ-A, OrmerodE.Pet ownershipandhumanhealth:abriefreviewofevidenceandissues.British MedicalJournal2005;331_:1252–5.

6.NashefL.Suddenunexpecteddeathinepilepsy:terminologyanddefinitions. Epilepsia1997;38_:S6–8.

7.ScorzaFA,deAlbuquerqueM,AridaRM,CavalheiroEA.Suddenunexpected deathinepilepsy:arewintertemperaturesanewpotentialriskfactor?Epilepsy &Behavior2007;10:509–10.

8.Sto¨llbergerC,WegnerC,FinstererJ.Seizure-inducedTakotsubosyndromeis more frequentthanreported.InternationalJournalofCardiology2011;150: 359–60.

9.StrongV,BrownS,HuytonM,CoyleH.Effectoftrainedseizurealertdogson frequencyoftonic–clonicseizures.Seizure2002;11:402–5.

10.TomsonT,NashefL,RyvlinP.Suddenunexpecteddeathinepilepsy:current knowledgeandfuturedirections.LancetNeurology2008;7:1021–33. 11.VlooswijkMC,MajoieHJ,DeKromMC,TanIY,AldenkampAP.SUDEPinthe

Netherlands: a retrospective study in a tertiary referral center. Seizure 2007;16:153–9.

12.WellsDL,LawsonSW,SiriwardenaN.Canineresponsestohypoglycaemiain patientswithtype1diabetes.JournalofAlternativeandComplementaryMedicine 2008;14:1235–41.

13.WalczakTS,LeppikIE,D’AmelioM,RarickJ,SoE,AhmanP,etal.Incidenceand riskfactorsinsuddenunexpecteddeathinepilepsy:aprospectivecohortstudy. Neurology2001;56:519–25.