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					      Evaluation Syncope
               of

     W.Richard
             Bukata,
                  MD               T h e a s s e ssment pati ents presenti ng w i th a hi story of syncope can be ver y
                                                         of
                                   challenging.    The list of causes syncopeis enormousand not easily remembered,
                                                                    of                                               yet
            Professor
     Clinical      of
                                   many of these etiologies can be life-threateningand, thus, cannot be overlooked. An
     Emergency Medicinethe
                       at
     LosAngeles      /
                County             extensiveliteraturebase exists regardingthe assessment syncope(but little of it is
                                                                                             of
     University
              ofSouthern           from randomizedtrials) and a plethora of tests(many quite costly) can be orderedin an
     CalilomiaMedical
                   Center;                                the
                                   attemptto diagnose causeof syncope.
     MedicalDirectorthe
                  of
     Emergency Department at
                                   Given that this is such a complex, yet important topic, it seemsto be one that is
     San       Valley
         Gabriel    Medical
           in
     Center San  Gabriel,          amenableto the developmentof guidelines so that physicianscan be assistedin
     California;
              Medical
                    Editor of      a p p ro a c h i ngthese pati ents i n a consi stent,evi dence-based,egal l y-def ensible,
                                                                                                           l
     Emergency Medical             cost-effectivemanner.
     Abstracts                     However, on accessing National GuidelineClearinghouse
                                                                the                                   (NGC) it was found that
                                   only two organizations      have developed  and endorsed   guidelinesfor the assessment and
                                   treatmentof syncope- the American Collegeof Physicians(ACP) / American Society
                                   of Internal Medicine and the EuropeanSociety of Cardiology (ESC). Somehow the
                                   guidelines developedby the American College of Emergency Physiciansthat were
                                   publishedin the Annals of EmergencyMedicine in June of 2001 were not included in
                                   the NGC citations.
                                   As an aside,the NGC (http://www.guideline.gov/body_home_nf.asp?view=home)             is an
                                   excellent resourcedevelopedto assisthealth care providers and others in finding and
                                   comparingauthoritative        guidelines.The NGC, asidefrom its apparent    omissionof the
                                   ACEP guidelines,is claimed to be a comprehensive              database evidence-based,
                                                                                                            of
                                   clinical practiceguidelinesand relateddocuments,        althoughclearly it missedinclusion
                                   of the ACEP guidelines.It is producedby the Agency for HealthcareResearchand
                                   Quality (AHRQ) (formerly the Agency for Health Care Policy and Research
                                   [AHCPR]), in partnership         with the American Medical Association(AMA) and the
                                   AmericanAssociationof HealthPlans(AAHP).
                                   Although a small textbook could be written on syncope,it is the purposeof this essay
                                   to hone down and focus on the initial assessment the syncopalpatient using these
                                                                                           of
                                   three setsof literature-based      guidelinesas a reference. The ACP and ESC guidelines
                                   can be accessed       via the NGC site. The two-part ACP/ASIM guidelineswere also
                                   publishedin the June l5th and July lst issuesof the Annals of Internal Medicine
                                   (1997), while the ESC guidelines were published in the August, 2001, issue of the
                                   EuropeanHeart Journal.
                                   Were it not difficult enoughto assess      syncopealone,a more basicquestionin patients
                                   is whetherthey were truly syncopalor not. Sometimea mixed picture can be present
                                   (e.9., a patient may have a brief seizure as the results of transient poor cerebral
                                   perfusionthat precipitated syncope).
                                                                   the          Was it just a dizzy spell in which the patients
                                   thought they were going to faint? Clearly, it would appearsafestto assumethe worst
                                   and evaluatethesepatientsusing the "syncope"algorithm. Specificallyexcludedfrom
                                   this discussionare patientshaving syncopein association         with ongoing symptomsas
                                   may occur with aortic rupture, pulmonary embolism, myocardial infarction, intracranial
                                   hemorrhage,       cardiac tamponadeand the like.
                                   All three sets of guidelines stressthe fact that the initial history and physical, if
                                   carefully performed and appropriatelyfocused, when combined with an EKG, will




8   lsraeliJournalof EmergencyMedicineVol 3, No. 2, May 2003
                                                                       Orlginal Article



likely be able to identify the causeof syncope in about half of the patients.The ESC
guidelinesalso recommendthat orthostaticvital signsbe a consistentpart of the routine
evaluationof thesepatientsas well.

FourMajorCategories Causes Syncope
                  of     of
To make the diagnosisof the causeof syncope,the basic pathophysiologicmechanisms
need to be considered. The following is basically the categoization adopted by the
ACP guidelines:
l. Neurally MediatedSyncope
Syncopeassociated         with inappropriatevasodilatation,bradycardiaor both.
a. Vasovagal syncope is often associatedwith a sensationof increasedwarmth and
   may be accompaniedby nausea.It may occur after exposureto an unexpectedor
   u n p l e a s a n tsi ght, sound or smel l , fear, severe pai n, emoti onal di stre ss and
   instrumentation.It may also occur in associationwith prolonged standing or
   kneeling in a crowded or warm place or on exertion (all three latter scenariosmay
   also be due to autonomicfailure)
b. Situational syncope occurs during or immediately after coughing, micturition,
   defecationor swallowing. Syncope associated          with throat or facial pain, however,
   may be due to glossopharyngeal trigeminal neuralgia
                                         or
c. Carotid sinus syncopecan be associatedwith neck pressure(shaving, tight collar)
   or headturning
2. OrthostaticSyncope
Occurs when there is documentedhypotensionassociated    with syncopalor presyncopal
symptoms.According to ECS guidelines,orthostaticblood pressures recommended
                                                                   are
to be taken after five minutes of being supine.Measurements repeatedafter one and
                                                           are
three minutes of standing and further continued if blood pressureis still falling after
three minutes or until symptomatic.A decrease more than 20mm Hg in the systolic
                                                of
pressureis consideredabnormal as is a drop in pressurebelow 90mm Hg independent
of the developmentof symptoms.

3. Neurologic Syncope
Neurologic causesof apparentsyncopeinclude seizures,              TIAs, migraine headaches and
subclavian steal syndrome. Confusion after "syncope" that lasts more than five
mi n u te s , to n g u e bi ti ng, i nconti nence,epi l epti c aura suggestthi s di agno sis. A
significant differential in the blood pressureof the two arms suggests       subclaviansteal.
4. Cardiac-Related   Syncope
By far, the potentially most dangerousform of syncope falls into this class. Patients
with know cardiac diseaseand syncopehave a significant incidence of cardiac-related
death. Unfortunately, many patients with syncope may be unknown to have cardiac
disease, and, as such, dependingon the nature of the history and the age of the patient,
a relatively aggressivesearch for cardiac problems may be necessary.The major
categoriesof cardiac diseaseassociated       with syncope are ischemia,valvular and
anhythmic.
Physicians should be aware that a variety of drugs can be associatedwith syncope,
some as a result of relatively benign causes(orthostatichypotension)while othershave
been associated  with lethal ventricular anhythmias. Drugs of particular concerninclude
antianginalagents,diuretics, antihypertensives,   antidepressants,  antiarrhythmicsand
drugs associated  with QT prolongation.A list of drugs associated with QT prolongation
and/or that induce torsadesde pointes has been compiled by Raymond L. Woosley,
MD, Vice Presidentfor Health Sciencesat University of Arizona Health Sciences
Center and is availableat www.qtdrugs.org/.



                                       2003rND,2 ll)rl ,3 il91n1nNl9l) r)N'lurritnyil tn)         9
      Original Article



                                  Clinical   to            of
                                                      Causes Syncope
                                         Clues Specific
                                 If you don't ask the right question, you won't get the right answer. Specifically, if
                                 physiciansdon't systematically        ask questionsthat will guide them to the causeof
                                 syncope,they won't be likely to diagnosethe cause.In performing the history, it is
                                 particularly important to focus on questionsthat will help differentiate the causeof a
                                 patient'sepisodeof syncope.The following list was adaptedfrom
                                 http://www.homestead.com/emguidemaps/files/syncope.           htm#clue.
                                 l. Sudden    syncope restwhen non-erect
                                                       at                               a                   or
                                                                              suggests cardiacarrhythmia atrial myxoma
                                 2. Sudden syncopeon exertion suggestsaortic stenosis,hypertrophicobstructive
                                      cardiomyopathy
                                 3. Preceding"lightheadedness"        prodrome with sweatingand nauseawhen erect that
                                      has a slow, progressive   onset suggests   vasovagalsyncope(orthostatic     hypotension
                                      would not likely have the sweating and nauseaand is anothercause of syncope
                                      precededwith lightheadedness)
                                 4. Preceding     palpitations          a
                                                              suggests cardiacanhythmia
                                 5. Precedingor accompanying          dyspneasuggests     pulmonary embolism (PE), tension
                                      pneumothorax,cardiactamponadeand air embolism
                                 6 . Pre c e d ingchest pai n suggests    myocardi al i schemi a,P E , cardi ac tam ponade,
                                      dissecting  aneurysm, and mitral valve prolapse
                                 7. Precedingor accompanyingback pain suggestsdissectingaortic aneurysmor
                                      leaking abdominalaortic aneurysm
                                 8 . Pre c e d ing or accompanyi ng abdomi nal pai n suggestsa l eaki ng a bdom inal
                                      aneurysmor ectopic pregnancy
                                 9. Occurring when turning head side to side, shaving or with neck compression
                                      suggests  carotidsinussyncope
                                 10.Occurringwhen exercising upperarrn suggests
                                                                   an                       subclavian  stealsyndrome
                                 I l. Occurringduring (or immediatelyafter) coughing,laughing,vomiting, swallowing,
                                      urination, defecation,combing hair or stretchingsuggests      situationalsyncope
                                 12.Occurringafter prolongedstandingsuggests          vasovagal   syncope
                                 13.Occurring after an emotional upset suggests         either vasovagalsyncope,prolonged
                                      QT syndromeor torsadesde pointes
                                 14.Recentillicit drug use suggests cardiacanhythmia,air or foreign body embolism
                                                                        a
                                 15.Syncopeassociated      with a sudden   headache  suggests subarachnoid
                                                                                                a              hemorrhage
                                 16.Recentneurologicsymptoms        suggests brain stemstroke,vertebrobasilar
                                                                             a                                   insufficiency,
                                      basilarmigraine,carotidor vertebral   arteryaneurysm aorticdissection
                                                                                             or
                                 17.Recentvaginalinsufflationsuggests air embolism
                                                                             an
                                 18.Recentblack stoolssuggest GI bleed
                                                                    a
                                 19.Recentfluid loss (vomiting, diarrhea,      sweating)or poor intake suggest   hypovolemia
                                      and orthostatichypotensionor Addisonian crisis
                                 20. Postprandialsyncopeis associated       with a recentmeal
                                                      or
                                 21. Polypharrnacy sildenafilsuggest        orthostatic  hypotension a causeof syncope
                                                                                                      as
                                 22. A history of known cardiac ischemia or structural heart diseasesuggestsa cardiac
                                      arrhythmia or a drug-inducedarrhythmia or cardiac valvular dysfunction
                                 23. A history of a mechanicalheart valve can be associated          with syncopecausedby
                                      valve-relatedthrombosis
                                 24.Cancer, obesity, pregnancy,recent surgery or trauma, prolonged bed rest and prior
                                      thromboemboliceventssuggestthe presence a pulmonary embolism as the cause
                                                                                       of
                                      of syncope.
                                 25. A history of autonomic dysfunction manifestedby impotence,anhydrosis,sphincter
                                      dysfunction can be associated    with orthostatichypotension-related   syncope.
                                      Next month we'll cover key aspects the physicalexam in assessing
                                                                             of                                   syncopeand
                                      the role of diagnostic tests.


l0   lsraeli
           Journalof Emergency      Vol
                             Medicine 3, No. 2, May 2003
                                                                                       Origtnal Article



The obtaining of a history that effectively addresses various mechanismsby which
                                                    the
syncopecan occur, and the diagnostic entities responsible,is likely to be the most
rewarding effort in the assessment the syncopal patient. There are, however, some
                                    of
very specific elementsof the physical exam that can be particularly rewarding when
assessingsyncopeand a variety of teststhat may add additional useful information.

ThePhysical
          Examination the Patient
                    in          with Syncope
Although the history is likely to have narroweddown the likely causeof syncopein
any one patient, a systematicexamination,focusing particularly on the cardiovascular
and neurologicsystems, essential.
                        is
Orthostatic Vitals
Orthostatichypotensionhas been implicated as the causeof syncopeby various studies
i n 4 V a - 1 2 7 o f c a s e s .T h e c o m b i n a t i o n o f o l d e r a g e a n d c o n c o m i t a n t u s e o f
                  o
antihypertensive       and/or antidepressant         agentsand/or vasodilatoryantianginalagents
clearly predisposes orthostatic syncope.Autonomic insufficiency and hypovolemia
                          to
may also be detectedon orthostatic testing. Customarily orthostatic hypotensionis
defined as a drop in systolic blood pressureof 20mm Hg or more when going from the
supineto standingpositionafter waiting two minutes.
Unfortunately, orthostatic hypotensioncan be present in asymptomatic individuals as
well, so the test is not particularly sensitivenor specific. In fact, positive orthostatic
changeshave been documentedin up to 40Voof asymptomaticpatientsover the age of
70 and in about a quarter of those younger than 60. Similarly, a goodly number of
children who are asymptomatichave been documentedto have orthostatichypotension
as well. A differential blood pressurein the arrnsexceeding20mm Hg is abnormal and
suggests    subclavian    stealsyndromeor aortic dissection.
Cardiovascular Exam
An examinationof the neck specifically noting the presence absence carotid bruits
                                                                 or          of
a n d th e p re s e n ceof neck vei n di stenti on i s appropri ate.C aroti d si nus syncope
(resulting from reflex-mediatedbradycardia and hypotension) can be the result of
carotid compression(tight collar, neck pressure)or a hypersensitive              baroreceptor
response. loud bruit could suggestsubclaviansteal syndrome or carotid artery
                 A
d i s s e c ti o n .T h e presenceof neck vei n di stenti on may suggestthe di agno sisof
congestiveheart failure (a known cause of arrhythmic suddendeath) or pericardial
tamponade.
The presence an unusually slow, fast or irregular cardiac rhythm should be soughtas
                     of
the cause of syncope and, in addition, it is important to determine whether any
murmurs are present.Aortic valvular pathology is particularly associated       with syncope.
Specifically, exenional syncopeis characteristicof tight aortic stenosis(cardiac output
is unable to keep up with demandin this setting).Typically this occurs in elderly
patients.It also seemsthat there is a predispositionto cardiac anhythmias in conditions
associatedwith aortic area pathology in the heart, e.g., idiopathic hypertrophic
subaorticstenosis         (IHSS).

Miscellaneous ltems on The Physical Exam
As noted in the introduction to this seriesof essays,we are focusing on transient
episodes syncopewithout ongoing symptoms.Clearly syncopecan be the presenting
        of
symptom of a ruptured aortic aneurysmor ectopic pregnancy,a large pulmonary
embolism or some other entity in which patients can be expectedto have ongoing
symptomsafter the initial syncopalepisode,and as such, they will not be discussed




                                                2003rNll ,2 1lr)r1 il9lnT i'lNlgl) r)Nlturnnlrn tn)
                                                                 ,3                                                      1l
     Original Article



                                 here. There are, however, a number of findings that should be sought on the physical
                                 exam that will be helpful in evaluating the syncopalpatient. The presence
                                 of incontinenceor of tongue biting (particularly along the sides) is consistentwith
                                 a significant seizure (although it is not uncommon for syncope to be associatedwith
                                 someconvulsive movementsas the brain becomesischemic).

                                                               in          of
                                                         Testing the Setting Syncope
                                                Adjunctive
                                 EasilyAccessible
                                 The Electrocardiogram
                                 Most guidelines advise that EKGs be routinely obtained unless the diagnosis is
                                 otherwiseclear cut. Some authorshave claimed that about 57oof patientswith syncope
                                 will have the diagnosis made via an EKG or rhythm strip. Some of the abnormalities
                                 that are observedon an EKG may have an unlikely relationshipto syncope(e.g., stable
                                 left bundle branch block), while others will clearly reflect the etiology (e.9., a short run
                                 of ventricular tachycardia).There is some value in maintaining a patient on a cardiac
                                 monitor during the emergency departmentevaluation of syncope in the hope of
                                 demonstratinga transientanhythmia not noted on the EKG. Abnormalities on the EKG
                                 that should be specifically soughtare:
                                 a. Previousor acutecardiac ischemic changes
                                 b. Signs of pericarditisor electrical alternans(cardiactamponade)
                                 c. LVH (hypertension,    aortic stenosis,HOCM)
                                 d. RVH (PE or pulmonary hypenension)
                                 e. Classical/non-specific  ECG signsof PE
                                 f. WPW or Lown-Ganong-Levinesyndrome
                                 g. LBBB or bifasicularblock (conductingsystemdisease)
                                 h. Bradyarrythmiasor tachyarrhythmias
                                  i. Long QT interval
                                 j Brugada syndrome (a familial dysrhythmic syndrome characterizedby partial
                                      RBBB with elevatedST segments leadsVl-3 and peculiar downslopingof the
                                                                          in
                                      elevatedST segments   with inverted T waves in those leads)
                                  k. Anhythmogenic right ventriculardysplasia(RBBB, QRS complex > I l0 msec in
                                      leadsV I -3, invertedT wave or epsilonwave)

                                 LabTests
                                 All three sets of guidelines make it clear that blood counts and comprehensive
                                 chemistry panelsdone without concomitantsuspicionof abnormalitieshave a very low
                                 yield in the setting of syncope.The ACP guidelines note that in syncope studies
                                 (including patientswith seizures),2-37o patientshad hypoglycemia,hyponatremia,
                                                                           of
                                 hypocalcemiaor renal failure. Specifically, the position of the ACP is:
                                 "Routine use of basic laboratory tests is not recommended;these test should be done
                                 only if they are specifically suggestedby the results of the history or physical
                                 examination. Pregnancytesting should be consideredin women of child-bearing age,
                                 especiallythosefor whom tilt- table or electrophysiologictesting is being considered."
                                 Here'swhat the American College of EmergencyPhysiciansguidelinesspecifically say
                                 concerningthe value of lab testing in this setting:
                                 "In an evaluation of syncope,blood tests rarely yield diagnostically useful information
                                 and their routine use is not recommended."
                                 The European Society of Cardiology guidelines support the position of the ACP and
                                 ACEP guidelinesstating:
                                 "Basic laboratory tests are only indicated if syncopemay be due to loss of circulation
                                 volume, or if a syncope-likedisorderwith a metabolic causeis suspected."




l2   lsraeli                        Vol
                             Medicine 3, No. 2, May 2003
           Journalof Emergency
                                                                                          Original Article



Otherlesfs
Although there are a large variety of teststhat can be used in the evaluationof syncope,
we will only discuss here tests that are generally immediately available. Tests for
neurally mediated syncopeare the tilt table test and carotid sinus massage. the two                        Of
tests, carotid massageis easily performed and most readily available, while tilt table
testing requires a table that will take a patient from 60 degreesto horizontal and, as
such,is not routinely available.
The ECS guidelines advise that carotid sinus massage recommendedin patientsover
                                                                            is
the age of 40 with syncope of unknown cause after the initial evaluation.Massage
should be avoided in patients with bruits and in those at risk for stroke (prior TIA or
stroke within the last three months, except when carotid diseasehas been ruled out by
imaging studies).
EK G a n d c o n ti nuous bl ood pressuremoni tori ng duri ng massagei s cons ider ed
mandatory. Intermittent measurementof blood pressureis specifically not advised
becausethe drop in blood pressurethat may occur may be substantialbut very
transient.Initially the massageshould be done on the right carotid artery with massage
l a s t i n g f o r f i v e t o t e n s e c o n d sa n d p e r f o r m e d a t t h e a n t e r i o r m a r g i n o f t h e
sternocleidomastoid the level of the cricoid cartilage.A positive responseis defined
                               at
as asystolelasting three secondsor more and/or a drop in the systolic blood pressureor
50mm Hg or more. Becausesome nonsyncopalpatients can also have a positive
response,presyncopalsymptoms should accompanya positive responsefor the test to
be truly diagnostic.
Some advise performing the procedurewith the patient initially in the supine position.
If there is no positive responseafter several minutes, compressionof the left carotid
can then occur. The ECS suggests                 that the test also be performed in the upright position
if supinetestingis negative.
Echocardiographyis another commonly available test; however, in the absenceof
clinical, physical or EKG findings suggestiveof cardiac abnormalities,diagnosticyield
can be anticipatedto be low. Although mitral valve prolapse is likely to be the most
commonly found abnormality, its relationship to syncope is probably coincidental in
m o s t c a s e s .E x ampl es of cardi ac di seasei n w hi ch there can be expectedt o be
echocardiographicabnormalities include: valvular disease(most frequently aortic
stenosis),cardiomyopathies,                 regional wall motion abnormalities,                   infiltrative heart
disease(e.g., amyloid), cardiac tumors, aneurysmsand atrial thrombi. It is observed
that echocardiography              can be useful in stratifying syncopal risk as being cardiac in
origin by identifying whether manifestationsof heart diseaseare presentand, if so, by
determining its severity.Echocardiographyis likely to make the definitive diagnosisof
the causeof syncopeonly in the presence severeaortic stenosisand atrial myxoma.
                                                          of

          for
lndications Admission Syncope
                    for
The three sets of guidelines all include admissionrecommendations.           ACEP advises
a d m i s s i o n fo r a ny pati ent w i th syncope and a hi story or physi cal evi dence of
congestive heart failure, ventricular arrhythmia or valvular heart disease,those with
chest pain or findings compatible with an acute coronary syndrome and those with an
E KG d e m o n s trati ngi schemi a, prol onged QT i nterval or bundl e branch block.
Admission should be consideredfor those over the age of 60, those with known
coronary artery diseaseor congenital heart disease,a familial history of suddendeath
and younger patients with exertional syncope without an obvious benign etiology for
the syncope.




                                                  2003rND,2 1lt)tl ,3 ilglnT ilNl9t) r)N'lurrit
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     Original Article


                                                \..
                                   To this list ofpatients advised to be admitted, the ACP recommendationsadd those
                                   who are on medicationsassociated     with arrhythmiasand patients with symptoms
                                               of
                                   suggestive a TIA or stroke. The ECS extendsthe admissionrecommendations            to
                                   include anyone having syncope associated     with exerciseand those with syncope
                                   associated  with severeinjury. They also suggestthat "occasionally"the following
                                   patientsmay need to be admitted for diagnostictesting - patientswithout heart disease
                                   but with suddenonset of palpitationsshortly before syncope,those having syncope
                                   while supine,patientswith frequent recurrentepisodesand those with minimal or mild
                                   heartdisease                             for
                                                 when thereis high suspicion cardiacsyncope. would seemthat all of
                                                                                                It
                                   these latter patients would warrant routine admission rather than "occasionally."
                                   Finally, admission is advised for those patients with cardioinhibitory,
                                   neurally-mediated  syncopewhen pacemaker   implantationis planned.




                                   The articlewas published the "Emergency
                                                          in                    and
                                                                         Medicine AcuteCareEssays"   Volume  26,
                                           7
                                   Number July2OO2 Volume Number August
                                                      &       26,      I       2002,and has beenreprinted the
                                                                                                        with
                                   permission theauthor.
                                             of




                                   Response
                                   TheEvaluation Syncope: Neurologisf's
                                               of       The           Perspective
                                   llan Blatt, MD
                                   Epilepsy     and
                                           Clinic EEGLab,                  The
                                                         DepartmentNeurology, Chaim
                                                                 of               ShebaMedical
                                                                                            Center,
                                   Tel-Hashomer, theTel-Aviv
                                                and              Sackler
                                                          University        of
                                                                       School Medicine

                                   Emergency departmentphysicians usually have the privilege of obtaining a first-hand
                                   history of the syncopal event from the patient and eyewitnesses.  Dr. Bukata correctly
                                   statesthat a properly taken history is likely to be the most rewarding effort in the
                                   a s s e s s ment the pati ent w i th syncope.H e emphasi zes
                                                  of                                             that the hi st or y should
                                   effectively addressthe various precipitating mechanismsand diagnosticentities. Many
                                   patients are subsequently    referred to a neurologist,who only receivessecond-hand,
                                   indirect information, including the emergencydepartmentdischargesummary. This
                                   summaryoften containsa variety of laboratory and ancillary test resultsbut a very brief
                                   history, which leavesmany questionsunanswered. may even be misleadingwhen
                                                                                         It
                                   any motor manifestation labeledas "generalized
                                                             is                       convulsions".
                                   The most common question,which then confronts the neurologist,is distinguishing
                                   between a convulsive syncopeand a true seizure.This topic is well covered in several
                                   publications,   notably those contributedby Dr. Lempert (1,2).The term "convulsive
                                   syncope" specifies a common variant of syncope that is accompaniedby tonic or
                                   myoclonic activity. Convulsionsare an integral componentof the brain's response       to
                                   hypoxia; they representthe rule rather than the exception.Whether or not syncope
                                   manifestswith convulsionsdependson the degreeof cerebralhypoxia. In contrastto an
                                   epileptic seizure,which is a cortical phenomenon,   muscleactivationduring syncopeis
                                   subcortical and originatesfrom abnormal firing of the reticular formation in the lower


14 lsraeliJournalof EmergencyMedicineVol 3, No. 2, May 2003

				
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