Ver el código de «Syncope»

''For pediatric patients patients see [[syncope (peds)]]''
==Background==
*Transient loss of postural tone and consciousness due to cerebral hypoperfusion
*Syncope and pre-syncope assessed similarly
*Important considerations:
**Is this true syncope or something else (eg, [[Stroke (main)|stroke]], [[seizure]], [[Head trauma (main)|head injury]])?
**If this is true syncope, is there a clear life-threatening cause?
**If this is true syncope and the cause is not clear, is the patient at high risk for serious outcome?

===Risk Factors for Serious Cause===
*Exertion preceding the event
**Note that syncope during exertion much more concerning than syncope after exertion
*No preceding symptoms
**Concerning for cardiac dysrhythmia
*History of cardiac disease in the patient
*Family history of sudden death, deafness, or cardiac disease
**Consider unexplained deaths and deaths due to single vehicle accidents
*Recurrent episodes
*Recumbent episode
*Prolonged loss of consciousness
*Associated [[chest pain]], [[shortness of breath]] or [[palpitations]]
*Use of medications that can alter cardiac conduction

==Clinical Features==
===Physical Exam===
*Evaluate volume status
*Evaluate for [[head trauma|head]] and [[neck trauma]] (related to fall from syncopal event)
*Focus cardiac exam on detecting murmurs ([[aortic stenosis]], [[mitral regurgitation]], tricuspid stenosis)
*Evaluate for signs of [[heart failure]]
*Palpate abdomen for pulsating mass ([[AAA]])
*Rectal exam to eval for [[GI bleed]]
*Thorough [[neurologic exam]]
*Examine for possible sources of infection

===Clinical Features by Cause===
*'''Cardiovascular-mediated syncope'''
**Usually occurs without warning (absence of prodrome)
**History of structural heart disease
**Family history of sudden cardiac death
**Syncope during exertion 
**[[Chest pain]] or [[palpitations]] associated with syncope
**Abnormal [[ECG]]
*'''Neurally mediated syncope'''
**Trigger event (fear/pain, prolonged standing, warm environment)
**Prodrome of [[nausea/vomiting]], tunnel vision, [[dizziness|lightheadedness]], diaphoresis, warmth <ref>Romme JJCM, van Dijk N, Boer KR, et al. Influence of age and gender on the occurrence and presentation of reflex syncope. Clin Auton Res. 2008;18(3):127-133</ref>
**Associated with head movement or pressure on neck
*'''Orthostatic hypotension-mediated syncope'''
**After standing up
**Change in medications

==Differential Diagnosis==
{{Syncope causes}}

==Evaluation==
===Work-Up===
''ACEP only recommends [[ECG]] and H&P as must haves''
*[[ECG]]
**Perform on every patient, unless trigger clearly identified (i.e. following blood draw) and no risk factors
*Urine pregnancy


;Consider based on history/symptoms:
*CBC (or POC hemoglobin) & chemistry (or POC glucose)
*[[Troponin]]
**Not recommended to rule out A[[MI]] in patients with isolated syncope<ref>Reed MJ, Newby DE, Coull AJ, et al. Diagnostic and prognostic utility of troponin estimation in patients presenting with syncope: a prospective cohort study. Emerg Med J. 2010; 27(4):272-276</ref>
**Elevated troponin predicts adverse cardiac outcome in syncope<ref>Reed MJ, Mills NL, Weir CJ. Sensitive troponin assay predicts outcome in syncope. Emerg Med J. 2012;29(12):1001- 1003</ref> 
**May be useful for risk stratification
*[[CXR]]
*Orthostatics (symptomatic)
*Guaiac
*CT scan of head is not recommended in asymptomatic, insignificant trauma with normal neurologic examination
**Part of [[Choosing wisely ACEP]]
*Does [[Pulmonary Embolism (PE)|PE]] need to be worked up?
**NEJM paper by Prandoni<ref>Prandoni P, Lensing AW, Prins MH, Ciammaichella M, Perlati M, Mumoli N, Bucherini E, Visonà A, Bova C, Imberti D, Campostrini S, Barbar S; PESIT Investigators. Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope. N Engl J Med. 2016 Oct 20;375(16):1524-1531. PubMed PMID: 27797317.</ref> showed that 7.14% of patients admitted for syncope had a pulmonary embolism and of the cohort that were not low risk with a negative d-dimer, the risk was as high as 17.3%
**2018 systematic reviewed <ref>Prevalence Of Pulmonary Embolism In Patients Presenting With Syncope: A Systematic Review And Meta-Analysis Oqab, Z., et al, Am J Emerg Med 36(4):551, April 2018</ref> showed 0.8% of admitted ED pts with syncope had PE
**Also supported by 2019 study showing prevalence of 2.3% in undifferentiated patients admitted with syncope<ref>Prevalence of pulmonary embolism in patients with syncope Badertscher P, du Fay de Lavallaz J, Hammerer-Lercher A, et al. J Am Coll Cardiol. 2019;74(6):744-754.</ref>.
**Both of these two studies refute the findings of the PESIT study listed first
*Bedside [[Ultrasound (main)|US]]
**PSL view may show thickened ventricular septum
**High sensitivity to rule out [[AAA]]

===Diagnosis===
*Overall yield of testing is low
*Cardiovascular findings and evidence of bleeding strongest predictors of adverse outcomes after syncope<ref> D’Ascenzo F, Biondi-Zoccai G, Reed M, et al. Incidence, etiology and predictors of adverse outcomes in 43,315 patients presenting to the emergency department with syncope: an international meta-analysis. Int J Cardiol. 2013;167(1)57-62</ref>
*[[ECG]] findings associated with adverse cardiac outcome in 30 days: <ref>Quinn J, McDermott D. Electrocardiogram findings in emergency department patients with syncope. Acad Emerg Med. 2011;18(7):714-718</ref><ref>Thiruganasambandamoorthy V, Hess EP, Turko E, et al. Defining abnormal electrocardiography in adult emergency department syncope patients: the Ottawa Electrocardiographic Criteria. CJEM. 2012;14(4):248-258</ref>
**Normal ECG has high NPV<ref>Sud S, Klein GJ, Skanes AC, et al. Predicting the cause of syncope from clinical history in patients undergoing prolonged monitoring. Heart Rhythm. 2009;6(2):238-243</ref>
**May show:
***[[Myocardial ischemia|ischemia]]
***[[Heart block]]
***[[WPW]]- short PR, Delta waves, wide QRS
***[[Long QT]] (QTc >0.450 sec), [[short QT]]
***[[Brugada]]- incomplete [[RBBB]] with ST elevations in V1-3
***[[HOCM]]- [[LVH]], ST changes, T wave inversions, lateral leads needle like Q waves and absent R waves
***[[Arrhythmogenic right ventricular dysplasia]]– incomplete [[RBBB]] with T waves inversion in V1-3, epsilon wave is pathognomonic (up-notching of a terminal Q wave)
***[[Early repolarization]]
***[[Low voltage ECG|low voltage]]/[[pericardial effusion]]
***RV strain pattern
***LBBB, 2nd degree Mobitz II, 3rd degree AV block, RBBB w/LAFP or LPFB

==Management==
*Treat underlying cause, if known (~50% of patients do not have a firm diagnosis)

==Disposition==
===Admit<ref>Huff JS, Decker WW, Quinn JV et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with syncope. Ann Emerg Med. 2007;49(4):431-444</ref>===
*Abnormal ECG
*[[CHF]]
*Suspicion of structural heart disease
**Ischemic, dysrhythmic, obstructive, valvular
*HCT <30
*[[Shortness of Breath]]
*[[Hypotension]](SBP <90)
*Family history of sudden cardiac death
*Advanced age
*Evidence of hemorrhage (occult blood)
*Syncope without prodrome
*Exertional syncope in younger patients without an obvious benign cause

===Discharge===
*None of the above findings (esp if age <45)
*No events on telemetry after period of observation (2-4 hours in the ED)
*Consider referral for holter or til-table test
*Instruct to avoid precipitating factors, such as extreme heat, dehydration, postexertional standing, alcohol and certain medications

==Additional Risk Stratification Tools for Selecting Low-Risk patients for Discharge==
===Canadian Syncope Risk Score<ref>Thiruganasambandamoorthy, V et al. Development of the
Canadian Syncope Risk Score to predict serious adverse
events after emergency department assessment of syncope.
CMAJ. 2016 Sep 6;188(12):E289-E298.</ref> [https://www.mdcalc.com/canadian-syncope-risk-score MDCalc]===
{| {{table}}
| align="center" style="background:#f0f0f0;"|'''Category'''
| align="center" style="background:#f0f0f0;"|'''No'''
| align="center" style="background:#f0f0f0;"|'''Yes'''
|-
| Predisposition to vasovagal symptoms (triggered by being in a warm crowded place, prolonged standing, fear, emotion, or pain)||0||-1
|-
| Heart disease history (CAD, afib, flutter, CHF, valvular disease)||0||1
|-
| SBP < 90 or > 180mmHg||0||2
|-
| Elevated troponin||0||2
|-
| Abnormal QRS axis ||0||1
|-
| QRS > 130ms||0||1
|-
| Corrected QT interval >480ms||0||2
|-
| Vasovagal syncope (based on clinical impression||0||-2
|-
| Cardiac Syncope (based on clinical impression)||0||2
|}

*Score < 0 associated with < 2% risk of serious adverse event at 30 days. 
*Externally validated per data presented at SAEM 2018 and only 0.3% 30 day adverse events for very low risk patients in 2020 Jama study <ref>Multicenter Emergency Department Validation of the Canadian Syncope Risk Score.  JAMA Intern Med. 2020 Mar 23. https://doi.org/10.1001/jamainternmed.2020.0288 </ref>

===[[EBQ: San Francisco Syncope Rule | San Francisco Syncope Rule]]===
*1.4% of patients who are rule-negative will have a 7-day serious outcome
*10% of patients meeting the below criteria will have a 7-day serious outcome

{{San_Francisco_Syncope_Rule}}

====Limitations====
*Performed poorly on external validation<ref name="Birnbaum">Birnbaum A, Esses D, Bijur P, Wollowitz A, Gallagher EJ. Failure to validate the San Francisco Syncope Rule in an independent emergency department population. Ann Emerg Med. 2008;52(2):151-9.</ref>
*External validation of San Francisco Syncope Rule showed sensitivity 90% but only specificity of 33% <ref> Thiruganasambandamoorthy et al, External validation of the San Francisco Syncope Rule in the Canadian setting. Ann Emerg Med. 2010 May;55(5):464-72. doi: 10.1016 </ref>

==External Links==
*[http://thennt.com/risk/syncope-in-the-emergency-department The NNT: San Francisco Syncope Rule Criteria]
*[https://www.mdcalc.com/canadian-syncope-risk-score MDCalc Canadian Syncope Risk Score]

==See Also==
*[[Dizziness]]

==References==
<references/>

[[Category:Cardiology]]