The Fainting Phenomenon: Understanding Why People Faint and What to Do About It, Second Edition PDF
Preview The Fainting Phenomenon: Understanding Why People Faint and What to Do About It, Second Edition
The Fainting Phenomenon UNDERSTANDING WHY PEOPLE FAINT AND WHAT TO DO ABOUT IT ToBarbaraStrausMD.Physician,wife,motherandsoulmate;andtoHelen andAlexnever-endingsourcesofprideandjoy;andtoPaulB.Grubb...may hismemorybeforablessing. The Fainting Phenomenon UNDERSTANDING WHY PEOPLE FAINT AND WHAT TO DO ABOUT IT Second Edition Blair P. Grubb, MD ProfessorofMedicineandPediatrics Director,CardiacElectrophysiologySectionand ClinicalAutonomicDisordersCenter UniversityMedicalCenter HealthScienceCampus UniversityofToledoSchoolofMedicine Toledo,Ohio,USA (cid:2)C 2001FuturaPublishingCompany,Inc.,NewYork (cid:2)C 2007BlairP.Grubb PublishedbyBlackwellPublishing BlackwellFuturaisanimprintofBlackwellPublishing BlackwellPublishingInc.,350MainStreet,Malden,Massachusetts02148-5020,USA BlackwellPublishingLtd,9600GarsingtonRoad,OxfordOX42DQ,UK BlackwellScienceAsiaPtyLtd,550SwanstonStreet,Carlton,Victoria3053,Australia Allrightsreserved.Nopartofthispublicationmaybereproducedinanyformorbyany electronicormechanicalmeans,includinginformationstorageandretrievalsystems,without permissioninwritingfromthepublisher,exceptbyareviewerwhomayquotebriefpassages inareview. Firstpublished2001 Secondedition2007 1 2007 ISBN:978-1-4051-4841-2 LibraryofCongressCataloging-in-PublicationData Grubb,BlairP. Thefaintingphenomenon:understandingwhypeoplefaintandwhattodoaboutit/ byBlairP.Grubb.–2nded. p. cm. Includesbibliographicalreferencesandindex. ISBN-13:978-1-4051-4841-2 ISBN-10:1-4051-4841-1 1. Syncope(pathology)–popularworks. I. Title. RB150.S9G782007 616(cid:3).047–dc22 2006025823 AcataloguerecordforthistitleisavailablefromtheBritishLibrary Acquisitions:GinaAlmond Development:BeckieBrand Setin9.5/12PalatinobyTechBooks,India PrintedandboundinHaryana,IndiabyReplikaPressPvtLtd. ForfurtherinformationonBlackwellPublishing,visitourwebsite: www.blackwellcardiology.com Thepublisher’spolicyistousepermanentpaperfrommillsthatoperateasustainableforestry policy,andwhichhasbeenmanufacturedfrompulpprocessedusingacid-freeandelementary chlorine-freepractices.Furthermore,thepublisherensuresthatthetextpaperandcoverboard usedhavemetacceptableenvironmentalaccreditationstandards. BlackwellPublishingmakesnorepresentation,expressorimplied,thatthedrugdosagesinthis bookarecorrect.Readersmustthereforealwayscheckthatanyproductmentionedinthis publicationisusedinaccordancewiththeprescribinginformationpreparedbythe manufacturers.Theauthorandthepublishersdonotacceptresponsibilityorlegalliabilityfor anyerrorsinthetextorforthemisuseormisapplicationofmaterialinthisbook. Contents Abouttheauthor,vii 1 Introduction,1 2 Thefaintingphenomenon,3 3 Thenormalnervoussystem,5 4 Thenormalcardiovascularsystem,15 5 Orthostaticintoleranceandorthostatic(postural)hypotension,33 6 Neurocardiogenicsyncope,47 7 Posturaltachycardiasyndromeandchronicfatiguesyndrome,55 8 Otherpossiblecausesoffainting,61 9 Faintinginchildrenandadolescentsandinolderpeople,67 10 Diagnosingtheunderlyingcausesoffainting,79 11 Treatingfainting,93 12 Wrappingup,107 Glossaryofusefulterms,109 Index,131 v About the author BlairP.Grubb,MD,isaProfessorofMedicineandPediatricsattheUniversity of Toledo, School of Medicine, in Toledo, OH. A native of Baltimore, MD, DrGrubbjoinedtheUniversity’sfacultyin1988,aftercompletingtrainingin cardiovasculardiseaseandelectrophysiologyatthePennsylvaniaStateUni- versity.Hehasbeeninvolvedinresearchintothecausesoffaintingandauto- nomicnervoussystemdisorderssince1988. Dr Grubb has written over 160 scientific papers and is the coeditor of a textbook for physicians on fainting (Syncope: Mechanisms and Management. BlackwellPublishingLtd.,2005).HereceivedtheUniversityofMaryland’sDis- tinguishedAlumnusAwardin1994andtheMedicalCollege’sDean’sAward forTeachingExcellencein1996,theLegacyofAchievementAwardfromthe NorthwestOhioAmericanHeartAssociationin2001,andthePhysicianofthe YearAwardfromtheNationalDysautonomiaResearchFoundationin2002.In 2006,hereceivedtheLeonardTowHumanisminMedicineAward.DrGrubb liveswithhiswifeBarbaraandhischildrenHelenandAlex.Forrelaxation,he writesandpublishesproseandpoetryandcollectsfountainpens. vii The Fainting Phenomenon: Understanding Why People Faint and What to do About It, Second Edition Blair P. Grubb Copyright © 2007 by Blair P. Grubb CHAPTER 1 Introduction TheFaintingPhenomenonisintendedtohelpthelargenumbersofpeoplewhose lives are negatively affected by the threat—and the reality—of fainting. Re- searchhasdiscoveredalotaboutwhatcausesfainting.However,wehavea longwaytogo,especiallyineducatingbothphysiciansandthepublic. Wenowknowthatthebrainandtheautonomicnervoussystem(ANS)auto- maticallyregulatemanyofthenormalfunctionsofthebody.Thisisespecially truewhenthefunctionsareoutsideofyourconsciouscontrol,suchascontrol ofyourheartrate,bloodpressure,bodytemperature,andbowelfunction. Thinkofyourbrainasbeinglikeathermostat.Thethermostatinyourhome automaticallyinstructsyourheatingsystemtoturnonandoffinresponseto changesintemperature.Onceyousetthethermostat,youdonotusuallyhave tothinkaboutitafterthat.Butwhatifyourfurnacesuddenlywasnotputting outtheheatneededtokeepyouwarm?Youmightassumethatsomethingis wrongwiththefurnace—allyouknowisthatyouarecold.Whatif,whenyou called in a repair person, you were told that there was nothing wrong with your furnace? Hopefully, the repair person would next think to check your thermostat to see if it was working properly. But think how you would feel if,insteadofcheckingthethermostat,therepairpersonconcludedthatyour blue-tingedskinandgoosebumps“mustallbeinyourimagination.” This is what can happen to someone with a disorder that causes fainting. Yourbrainandnervoussystemworkinmuchthesamewayasthethermostat. YouarenotnormallyawareofyourbrainandANSfunctioning,onlyofthe endresults...orlackofthem.Imagineasituationinwhichyouwenttoyour doctorandreportedthatyourheartseemedtostopattimes.Itwouldbeboth upsettingandfrustratingif,aftercheckingyourheart,yourdoctorconcluded thatsincetherewasnothingwrongwiththeheartitself,theproblemmustbe “inyourhead.”Inaway,thedoctormightberight,butnotthewayyouthink. Thestoppingofyourheartmightactuallybeduetosomemalfunctionofthe signalssenttotheheartfromthebrainandtheANS.Thefurnace—yourheart— mightcheckoutokay,butstillnotbeworkingproperlybecauseofproblems withthethermostat—yourbrain—orthewiringconnectingthetwo—theANS. Awholenewbranchofmedicinehasdevelopedtolookatsymptomscaused bymalfunctioningofyourbrainand/orANS. ItisinterestingtonotethatanumberofpeoplewithdisordersoftheANS havebeenmisdiagnosedashavingotherdisorders.Forexample,peoplewith sometypesofANSdisorderscanexperienceextremefatiguebecauseoftheway thebrainandANSregulatebloodpressureandheartrate.Theseindividuals 1 2 Chapter1 maybemistakenlydiagnosedashavingchronicfatiguesyndrome.Itisesti- matedthatasmanyas20%ofthepeoplediagnosedashavingchronicfatigue syndromemayactuallyhaveANSproblems.Whyisthisimportant?Thereis currentlynouniformlyeffectivetreatmentforchronicfatiguesyndrome.ANS disorders, on the other hand, can often be successfully treated, allowing the persontoreturntonormalfunctioning.Whenthecorrectdiagnosisismissed, it can be tragic for individuals who may continue to be almost totally inca- pacitated;theymaynotbeabletofunction.Thesymptomscanhavenegative effectsonallaspectsoftheirlife,includingpersonalrelationships,theability toholdajob,andenjoymentofhobbies,amongothers. Knowledgeispower!Itisimportantforyoutoknowthatsymptomssuchas faintingorchronicfatiguemaypossiblybeasignofadisorderofyourANS. Justbecausetheunderlyingcauseforthesesymptomsdoesnotshowupina basicphysicalexaminationorabloodtestisnotproofthatyourproblemsare psychosomatic,thatis,causedbypsychologicalinsteadofphysicalproblems. The Fainting Phenomenon: Understanding Why People Faint and What to do About It, Second Edition Blair P. Grubb Copyright © 2007 by Blair P. Grubb CHAPTER 2 The fainting phenomenon This book is all about fainting—losing consciousness and, unless something or someone prevents it, slumping to the floor. A faint usually does not last very long, and you typically regain consciousness within a few seconds or minutes, even when nothing is done to awaken you. (The medical term for fainting, which appears throughout this book, is syncope.) As you continue toread,youwillseethatthereisaverybroadrangeofunderlyingcausesfor syncope—thefaintingphenomenon.Someofthecausesarenottooseriousin themselves,whileotherscanbelethal. Fainting is no minor matter Fainting is more common than you might think. It is estimated that about one-third of all adults will experience at least one fainting episode at some timeintheirlife.Peoplewhoexperiencerecurringfaintingepisodescanhave areducedqualityoflife,comparabletothatresultingfromsuchdebilitating conditionsassevererheumatoidarthritisorlowbackpain.And,asyoumight imagine, the more frequent the fainting episodes, the greater the impact on qualityoflife.Oneexampleofanegativeeffectonthequalityoflifeisthatthe threatoffaintingmaybarsomeonefromsafelydrivingacarorothervehicle. Donotwriteofffaintingasaminorinconvenience—itcanposearealhealth risk.Itisestimatedthatfaintingaccountsfor3%ofallvisitstotheemergency roomandupto6%ofallhospitaladmissions.Peoplewhofaintwithoutwarn- ingcanbehurtwhentheyfall.Thesefallscancauseseriousinjuriessuchasa subduralhematoma(aleakageofbloodinthebrain)orfracturesofthebones intheface,skull,arms,andlegs.Inolderindividuals,asinglefaintingepisode cancauseinjuriesseriousenoughtorequirepermanentplacementinanursing home.AsAmericanhumoristWillRogersoncecommented,“it’snotthefall thathurts,it’sthatsuddenstopattheend.”Andrecurringfaintingepisodes aresometimestheonlysymptomthatprecedessuddendeath. What causes most faints? Faintingisasymptom,ratherthanadiseaseorcondition.Youtypicallyfaint whenthereisadecreaseintheamountofoxygen-carryingbloodflowingto yourbrain.So,faintingisactuallycausedbyashort-termreductioninblood pressuretoyourbrain—atypeoftemporarylowbloodpressure(hypotension). Adecreaseinbloodflowasbriefas8–10secondsmaycauseyoutofaint.When 3 4 Chapter2 thecellsofyourbrainarenotabletogetenoughoxygenfromyourbloodto functionproperly,youloseconsciousness. Sometimesyoumayfirstfeeldizzyorlight-headed—it’sawarningyouthat you are about to faint. Fainting often occurs when you sit up from a lying positionorstandupfromalyingorsittingposition.Aninabilitytomovetoan upright position without developing symptoms is called orthostatic (having todowithyourposition)intolerance.Orthostatic(postural)hypotensionisthe termusedtodescribeadropinbloodpressurethatoccurswhenyourposition orposturebecomesupright. If you fall when you faint, your blood pressure usually comes back up to morenormallevelsonceyouareontheground,allowingyoutoregaincon- sciousness. The rise in blood pressure may be due to your lying down, or sometimes the original cause of your fainting episode has passed. Keep in mindthattryingtogetuptooquicklymayleadtoyourfaintingagain. Undercertaincircumstances,evennormalpeoplemaydevelopthesymp- tomsthatoftenprecedeafaintorevenexperiencethefaintitself.Thiswould typicallybecausedbyacombinationofcircumstances.Letussaythatyouare inawarmenvironment,whichwouldcausethebloodvesselscarryingbloodto yourskintobecomelarger.Next,youhyperventilate—breathingmorerapidly than normal. This results in the blood vessels in your brain contracting, or becoming smaller. If you now suddenly stand up from a crouched position, bloodwillpoolinyourlowerbodyandhaveadifficultbattleagainstgravity toflowbackuptoyourbrain.Theresult:yougetsymptomsoryouactually loseconsciousness. Yourbloodpressurecanalsodropwhenyoulosealotofthefluidfromyour system,decreasingtheamountofbloodavailabletoreachthebrain.Thiscan resultfromdehydrationduetoexcessivesweatingorurinationorfromfluid lossesduringdiarrhea.Ofcourse,yourbloodvolumealsodropsifyourlose bloodduetoaninjury. Thereareanumberoffactorsthatcanloweryourbloodpressureandde- creasethesupplyofoxygentoyourbrain.Inthisbook,wewilldealinsome detailwiththemostcommoncausesunderlyingthefaintingphenomenonin peoplewhogotoadoctorforthisproblem. Looking forward... Tomakeiteasiertounderstandwhatcangowronginbloodpressurecontrol, wewillfirstlookathowyourbodynormallycontrolsbloodpressure.Chapter3 containssomeusefulinformationonthoseaspectsofthenervoussystemmost involvedincontrollingandmaintainingbloodpressure.
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