Syncope

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Syncope
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Definition

• Transient loss of consciousness due to reduced
  cerebral blood flow

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Major considerations

• Injuries occur in up to 35 of patients who have
  syncope
• Recurrent episodes can be psychologically
  devastating
• Syncope can be a sign of underlying disease

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Etiology of Syncope

• Cardiac- 23
• Neurally mediated- 58
• Neurologic or Psychiatric- 1
• Unexplained- 18

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Causes of Syncope

• Disorders of vascular tone or blood volume
• Vasovagal (neurocardiogenic)
• Orthostatic hypotension
• Drug induced
• Peripheral neuropathy
• Idiopathic
• Physical deconditioning
• Decreased blood volume

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Causes of Syncope

• Carotid sinus hypersensitivity
• Situational
• cough urination defication valsalva
  deglutination

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Causes of Syncope

• Cardiovascular disorders
• Arrhythmias
• Bradyarrhythmias
• Sinus bradycardia sino-atrial block sinus
  arrest sick-sinus syndrome
• Atrioventricular block
• Tachyarrhythmias
• Supraventricular tachycardia
• Atrial fibrillation with Wolff-Parkinson-White
  syndrome
• Atrial flutter

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Causes of Syncope

• Cardiopulmonary
• Pulmonary embolism
• Pulmonary Hypertension
• Atrial myxoma
• Myocardial disease (massive MI)
• Left ventricular restriction or constriction
• Pericardial constriction or tamponade
• Aortic outflow tract obstruction
• Aortic valvular stenosis
• Hypertrophic obstructive cardiomyopathy

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Causes of Syncope

• Cerebrovascular disease
• Vertebrobasilar insufficiency
• Basilar artery migraine
• Cerebrovascular accident

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Causes of Syncope

• Other disorders that may resemble syncope
• Metabolic
• Hypoxia
• Anemia
• Low CO2
• Hypoglycemia
• Psychogenic
• Anxiety attacks
• Hysterical fainting
• Seizures

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Modalities to determine etiology

• History
• Physical examination
• Tests/ Labs
• ECG

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History- Major Considerations

• History and PE can lead to dx in up to 45 of
  patients
• Prior history of heart disease is a strong
  predictor of a cardiac cause
• Occurs in supine position or during effort
• Blurred vision
• Convulsive syncope (not a seizure)
• Neurally mediated syncope
• Four years between episodes
• Abdominal discomfort before syncope
• Nausea and diaphoresis during recovery phase

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History

• Number of Episodes
• Benign causes- usually one episode
• Multiple episodes indicate an underlying disorder
• Associated Symptoms
• Dyspnea- think PE
• Angina- think cardiac
• Nausea, vominting, diaphoreses, pallor- think
  vagal
• Urination/ deficaiton- suggest seizure

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History

• Prodrome
• Nausea, warmth, pallor, lightheadedness, and/ or
  diaphoresis- think vasovagal syncope (also called
  neurocardiogenic syncope)
• Auras- think seizure
• Position
• Erect- think vasovagal
• Supine to errect- think orthostatic hypotenstion
• Supine- consider an arrhythmia

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History

• Warning
• Sudden loss of conciousness- think arrhythmia
• Preceding events
• This can include coughing, eating, drinking cold
  liquids, urinating, and defecating. This is
  referred to as situational syncope
• Duration of symptoms
• Prolonged- more indicative of seizure or aortic
  stenosis
• Brief- more indicative of an arrhythimia or
  vasovagal. The supine position returns blood flow
  to the head, even if the arrhythmia persists.

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History

• Recovery
• Nausea, pallor, diaphoresis- think vasovagal
• Prolonged confusion or neurologic changes- think
  stroke or seizure
• Witness
• Helpful for information about clonus, pallor,
  diaphoresis, or even absence of pulse

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History

• Exertional syncopy
• Causes ventricular tachycardia aortic stenosis
  hypertrophic cardiomyopathy
• Vasovagal syncopy is a diagnosis of exclusion in
  the case of exertional syncope
• Age
• Vasovagal syncope is more likely in young healthy
  individuals

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History

• Injury
• Syncopy may be an indication of an underlying
  disorder while the body is being stressed by the
  injury
• Pain can also lead to syncope
• Also consider significant hemodynamic comprimise
• Medications
• Primarily antiarrhythmics and antihypertensive
  agents
• Also consider EtOH and illicit drugs

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History

• Differentiating Seizures and Syncope
• Seizures
• Have a slow recovery (post-ictal confusion)
• Tonic clonic movements
• May have multiple injury sites due to tonic
  clonic movements
• May have cut tongue
• Prodromal Déjà vu/ aura
• Head turning to one side during loss of
  conciousness

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History

• Differentiating Seizures from Syncope
• Syncope
• Presyncope- lightheadedness
• Prodromal symptoms of diaphoresis or pallor
• Post LOC nausea, diaphoresis, and pallor
• Recent change in position to standing

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Physical Examination

• Vital signs
• Check for orthostatic hypotension
• Drop in systolic BP by 20 laying to standing, or
  drop in diastolic by 10
• Abnormal hearth rhythm
• Hyperventilation- consider PE or psychiatric
  cause

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Physical Examination

• Murmurs- suggestive of pulm stenosis, aortic
  stenosis, or atrial myxoma
• Physiologic maneuvers- valsalva
• Abnormal neurologic findings
• Unilateral deficits are suggestive of CVA
• Rectal exam-
• positive stool guaiac may indicate anemia/
  hypovolemia

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Physical Examination

• Carotid sinus massage
• May be indicative of baroreceptor hypersensitivity

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Testing

• ECG
• Ambulatory monitoring
• Continuous 24- 48 hour monitoring
• Event recorders
• Implantable loop recorder
• Echocardiography
• Neurologic testing
• EEG
• Brain CT, brain MRI, carotid doppler ultrasound

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Testing

• Exercise testing
• Useful in exertion related syncope
• Upright tilt table test
• Useful to confirm vasovagal syncope
• Lab
• BNP
• May be useful to distinguish cardiac from
  non-cardiac syncope

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When to Hospitalize

• Reasons to hospitalize
• Presence of serious injury
• Recurrent symptoms
• Old age
• Diagnosis or suspicion of cardiovascular or
  neurologic cause

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Treatment

• Overall- treat the underlying cause of the
  syncope
• Avoid stimuli that may have caused syncope
• Avoid situations where sudden loss of
  consciousness may result in injury
• Place patient in the supine position with head to
  side

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Treatment

• Pharmacologic treatment of vasovagal syncope
• Beta antagonists (metoprolol, atenolol, or
  nadolol)
• Serotonin reuptake inhibitors (paroxetine, or
  sertraline)
• Buproprion
• Hydrofludrocortisone- to treat volume depletion
  or orthostatic hypotension

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Sources

• www.uptodateonline.com
• Harrisons Internal Medicine
• American Heart Association http//circ.ahajournal
  s.org/cgi/content/full/113/2/316