Docstoc

Response

Document Sample
Response Powered By Docstoc
					     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
                                                                                        Original Article



brainstem. This may occur as a consequence direct hypoxic activation of reticular
                                                 of
 neuronsmediatedby chemoreceptors       and releasefrom conical inhibition (3). Reported
 frequencies of syncopal convulsions vary; when film or video recordings were
employed, myoclonus was observedin 90Voof 56 syncopalepisodesand additional
movements    in79Vo(2).
Clinically, the motor manifestations   may include myoclonicjerks, tonic posturingand
more complex movements.Myoclonus is often multifocal with asynchronousmuscle
jerks in different parts of the body, but may be generalizedwith a few jerks of bilateral
synchronous    muscle activation.Syncopalmyoclonusis not rhythmic and usually lasts
less than 30 seconds.   Tonic muscle activity during syncopetypically consistsof head
and body extension;the arms may be flexed or extended,and the fists may be clenched.
If tonic body extensionstartsearly in the courseof syncope,the fall may be stiff rather
than flaccid. More complex movementsmay simulate automatisms(which commonly
occur during complex partial seizures),   and may include vocalization.
Post-ictalconfusion and disorientationlasting longer than 30 secondsis useful in
distinguishingan epileptic seizurefrom a convulsive syncope.Tongue biting usually
indicates a seizure, but urinary incontinence and head injury are common in both
entities. Sheldon et al (4) devised a simple point score of historical featureswhich
distinguishes  syncopefrom seizures    with very high sensitivityand specificity.
The electroencephalogram often overusedand misusedin the evaluation of syncope.
                              is
A normal EEG does not preclude the diagnosis of a seizure disorder, the most
commonly reportedEEG abnormalitiesare not epileptiform, and interictal epileptiform
activity may support the diagnosisof epilepsy but does not rule out the possibility that
the episode in question may have been syncopal.The routine use of EEG in the
evaluation of syncope is not recommended;in a retrospectiveEEG review of 73
patients with syncope, 13.7Vo     had abnormal findings, but the final diagnosisand
treatmentwere affectedby the EEG findings in only one case(5).
Thus, there is no substitutefor a detailed history of the syncopal event, and if any
motor manifestationsare reported they should be documentedwith as much detail as
possible. No one is in a better position to glean this information than the emergency
medicinephysician.



References

1.   Lempert T. convulsive syncope.Medlink Neurology, Medlink corporation ,2003
2.   Lempert T, Bauer M, Sghmidt D. Syncope. a videometric analysis of 56 episodesof transient cerebral
     hypoxia. Ann Neurol 1994;36:233-7
3.   Dell P, !-ug-e]in A, Bonvallet M. Effects of hypoxia on the reticular and cortical diffuse systems. In:
     Gastaut f_I,^    V.y9. JS, editors. Cerebral anoxia and the electroencephalogram.         Springfield:-Charles C
     T h o m a s ,l 9 6 l : 4 6 - 5 8
4.   Sheldon R, Rose S, Ritchie D, Connolly SJ, Koshman ML, Lee MA, FrenneauxM, Fisher M, Murphy
     W. Historical criteria that distinguish syncopefrom seizures. Am Coll Cardiol 2002;40:142-8
                                                                          J
5.   Davis TL, Freemon                                          should not be routine in the evaluation of syncope in
                                     _n\ _ll^e^ctlggn-cephalography
     adults. Arch Intern Med 1990:l5O:2027-9




                                                2003rND,2 1lr)rl ,3 ilglnT i'lNlg]) r)N'lurrn
                                                                                            nyn tn)                     l5

				
DOCUMENT INFO