Syncope
UCI Internal Medicine Core
Curriculum – Mini Lecture
Asad Qasim – PGY3
Learning Objectives
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Understand the Definition of Syncope
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Know the Basic Etiologies of Syncope
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Know how to Work-up High vs Low Risk
Syncope
What is Syncope?
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Syncope is the abrupt and transient loss of
consciousness associated with absence of
postural tone, followed by complete and usually
rapid spontaneous recovery. The underlying
mechanism is global hypoperfusion of both the
cerebral cortices or focal hypoperfusion of the
reticular activating system.
What is Syncope?
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It is important to distinguish Syncope from other
causes of T-LOC (Transient Loss of Consciousness)
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Pre-Syncope: lightheadedness without LOC
Drop Attack: loss of posture without LOC
Coma: LOC without spontaneous recovery
Seizure: Tonic-Clonic Movements that start WITH LOC (vs
hypoxic myoclonus which can occur with syncope), postictal recovery period
Hypoglycemia
Hypoxia
TIA
Cardiac Arrest
Etiologies of Syncope
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Neurocardiogenic / Vasovagal
Most Common
Cardiovascular
Most Dangerous
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Pain/Noxious Stimuli
Situational (micturation, cough,
defecation)
Carotid Sinus Hypersensitivity (CSH)
Fear
Prolonged standing / heat exposure
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Arrhythmia – Tachy or Brady
Valve Stenosis (outflow obstruction)
HOCM (outflow obstruction)
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Drugs: BP meds, Diuretics, TCAs
Autonomic Insufficiency (Parkinsons,
Shy-Dragger, DM, Adrenal
Insufficiency)
Alcohol
Dehydration
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Psuedosyncope
TIA or Vertibro-basilar Insufficiency
Orthostatic Hypotension
“DAAD“
Neuro / Functional / Psychiatric - <5%
Work-up and Risk Stratification
•The syncope work-up should determine who is at HIGH
RISK for a dangerous short-term cardiac event.
•All patient should get basic Work-up Including
•History/Physical including Orthostatics
•Medication Review
•ECG.
•If age >40, consider Carotid Sinus Massage to assess for Carotid Sinus
Hypersensitivity
• CONTRAINDICATED if carotid bruit present or recent TIA/Stroke
• + Test = bradycardia, hypotension, transient pause/asystole, or prodrome symptoms
• All patients should then be Risk Stratified
• Adapted from AHA/ACCF Scientific Statement on the Evaluation of Syncope. (Circulation.2006;113:316-327)
Work-up and Risk Stratification
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Risk Stratification
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High Risk: These patients are at high risk for short term cardiac
mortality and need appropriate cardiac work-up as an INPATIENT
• Evidence of significant heart disease (such as heart failure, low left
ventricular ejection fraction, structural abnormality, or previous
myocardial infarction).
• Clinical (eg palpitations) or ECG features suggesting arrhythmia
• Comorbidities such as severe anemia or electrolyte disturbance.
• High Risk Work-Up
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Echo, Stress test, and/or Ischemic Evaluation
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Check for recent Echo and/or TMST before ordering a new one!
Consider Posterior Circulation imaging of the brain if suspect Neurological
“syncope”
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Carotid Ultrasound has POOR utility in the workup of Syncope and should not be ordered routinely.
Work-up and Risk Stratification
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Low Risk: Patient’s with no High risk characteristics
and/or with highly suspected Vasovagal or
Neurocardiogenic Etiology
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Single Episode: No further workup indicated
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Multiple Episodes: Can workup as outpatient
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Patient having FREQUENT Episodes: Holter Monitor or Event Monitor
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Patient having INFREQUENT Episodes: Implantable Loop Recorder
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These patients DO NOT need “ACS Rule Out” or Imaging (including
Head CT or Carotid Ultrasound)
Imaging in the Workup of Syncope
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So When do I get Brain Imaging?
• Neurological Causes of true Syncope are RARE
• Bilateral Carotid or Basilar Artery Disease
• Non-convulsive Seizure
• Head CT is indicated ONLY if the patient has or experienced
focal neurological deficits or they experienced head trauma from
the event.
• Carotid Ultrasound has LOW utility and should NOT be ordered
routinely.
• Posterior Circulation evaluation with CTA/MRA or Ultrasound is
useful only if Vertibro-basilar insufficiency is suspected
• Typically present with Dizziness, gait instability, blurry vision, nystagmus, or
frank Coma.
“Hey its Triage, have this syncope admit”
• 71y/o M presents after he passed out while walking up the
stairs. He felt slightly lightheaded just prior to the event. Wife
saw him fall but was able to quickly arouse him. He had no
incontinence or tongue biting. Similar event occurred 2 weeks
prior while he was doing yard-work for which he did not seek
medical care. He has a long history of DM, and hypertension
for which he takes Glipizide, Amlodipine, Lisinopril, and HCTZ.
He does not drink. Vitals, orthostatics, and blood sugar are
unremarkable. ECG shows left axis deviation and LVH. Exam
shows 1+ bilateral edema and 4/6 ejection murmur radiating to
the carotids.
• What risk category is this patient and how would you
proceed with workup?
“Hey its Triage, have this syncope admit”
• H/P, Orthostatics, ECG, Meds
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ECG shows evidence of structural heart disease and exam
shows murmur. No orthostasis or suspicious history of
vasovagal syncope. Patient has had multiple episodes.
• Based on initial workup, patient is High Risk
o Needs Admission and Cardiac Work-up including
Echocardiogram and Stress Test
 Dx: Aortic Stenosis
“Last admit of the day!”
35y/o healthy M presents with an episode of syncope while
standing. He did not experience any prodrome
symptoms. This has never happened before. He has no
medical history and uses no medications, drugs, or EtoH.
Physical exam and ECG are normal. No orthostasis.
Carotid massage is negative. Routine labs are
unremarkable.
• What risk category is this patient and how would you
proceed with workup?
Last admit of the day!
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H/P, Orthostatics, ECG, Meds - normal with no obvious cause of syncope
Patient is Low Risk and has had only a Single Episode of syncope
 No Further Work-up Indicated
What if the same patient presented with syncope while working out
at the gym and physical exam showed a grade III systolic murmur
that increased with Valsalva?
o Patient is now High Risk given possible structural heart disease and
exertional syncope
 Admit to telemetry for cardiac work-up including
Echocardiogram to evaluate for Hypertrophic
Cardiomyopathy.
Key Points
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Key Differential Dx
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Vasovagal/Neurocardiogenic - most common
Cardiac – HIGH RISK PATIENTS, most dangerous
Orthostatic – “D A A D”
Other - Neurologic, Functional, Psych
Work-up and Risk Stratification
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H/P, Orthostatics, Meds, ECG, +/- Carotid Massage
Risk Stratify
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High Risk - Admit w/ cardiac work-up
Low Risk - Outpatient workup based on frequency of episodes
Brain Imaging ONLY if focal Neuro Deficits or Head trauma
References
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AHA/ACCF Scientific Statement on the Evaluation of Syncope. (Circulation.2006;113:316-327)
ESC Guidlines for the Diagnosis and Management of Syncope. (European Heart Journal. 2009.
30;2631-2671)
UptoDate
Management of Syncope in the Emergency Department
Etiology and Pathogenesis of Syncope
Diagnosis and Management of Syncope in Adults
Cases Adapted from NMS Medicine Casebook. Tilak Shah 2009
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