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Definitions

• Distinguish from seizure: syncope often has triggers (emotion, pain), prodrome (dizziness, nausea), brief unconsciousness, no post-ictal state.
• Neurally mediated syncope: common, due to inappropriate autonomic reflex (e.g. vasovagal, situational syncope, carotid sinus hypersensitivity).
• Postural syncope: caused by orthostatic hypotension; common causes include drugs (antihypertensives, diuretics), hypovolaemia, autonomic failure.
• Arrhythmic syncope: caused by bradyarrhythmias (sick sinus syndrome, AV block) or tachyarrhythmias (VT, long QT syndrome); check for family history.
• Structural syncope: mechanical obstruction in the heart (e.g. aortic stenosis, hypertrophic cardiomyopathy), usually during exertion.
• Investigations: ECG, ambulatory ECG, echocardiography, tilt table testing, lying and standing BP, carotid sinus massage. </aside>

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Criteria for syncope

1. Loss of consciousness
2. Transient loss of consciousness (i.e. no intervention is needed for the patient to fully recover → cardiac arrest and hypoglycaemic coma are not considered syncope)
3. It is caused by global cerebral hypoperfusion (i.e. focal cerebral hypoperfusion from TIA is not considered syncope) </aside>

• History
  • History tips: ask about precipitants, prodrome, position, palpitations, post-event phenomena, colour, convulsions, continence, cardiac problems, family history of sudden cardiac death
    • The five Ps:

      • Precipitant

        • Vasovagal: fear, pain, blood phobia, prolonged standing
        • Situational: cough, sneeze, defecation, micturition, exercise, post prandial
        • Carotid sinus: shaving, tight fitting collars, sudden turning of the head
        • Structural: physical exertion
        • Standing from sitting
        • Working with arms elevated above head → subclavian steal syndrome

      • Prodrome

        • Progressive light-headedness
        • Visual disturbances (dimming of vision, epileptic auras)
        • Weakness or sensory disturbances of the extremities
        • Sweating
        • Nausea
        • Tinnitus

        ---

        • “Did you have any symptoms before you lost consciousness?”
        • “Did you notice any visual changes before your lost consciousness?”
        • “Did you feel nauseated or sweaty before you lost consciousness?”
        • “Did you notice any changes to your hearing before you lost consciousness?”
        • “Did you notice any weakness or changes in sensation before you lost consciousness?”
        • “Did you notice that your heartbeat became more prominent before you lost consciousness?”
        • “Did you experience any chest pain before you lost consciousness?”
        • “Did you notice any unusual smells or tastes prior to losing consciousness?”
        • “Did you experience any visual hallucinations prior to losing consciousness?”
        • “Did you experience a sense of déjà-vu prior to losing consciousness?”
        • “Did you experience any changes to the sensation of your body prior to losing consciousness?”
        • “Did you notice any twitching or weakness or your arms, legs or face prior to losing consciousness?”

      • Position

      • Palpitations

      • Post-event phenomena

    • The five Cs:
      • Colour
      • Convulsions
      • Continence
      • Cardiac problems
      • Cardiac death family history
  • Break down history into before, during and after
  • Syncope is strongly suggested by:
    • Rapid onset
    • Short duration (20 seconds → some minutes)
    • Spontaneous and complete recovery
  • Additional questions
    • “Did you see any evidence of injuries during or after the period in which they lost consciousness?”
    • “Did they fall as a result of the loss of consciousness?”
    • “Have you got any pain anywhere at the moment?”
    • “Did the patient hit their head at any point during the episode?”
    • “Did the patient vomit whilst unconscious and was there evidence of any loose objects within their mouth during or immediately after the episode?”
• Systemic enquiry
  • Systemic: fevers (e.g. cerebral abscess, meningitis), weight change (e.g. malignancy)
  • Neurological: visual symptoms (e.g. pre-syncope), headache (e.g. brain tumour), motor or sensory disturbances (e.g. stroke)
  • Cardiovascular: palpitations (e.g. arrhythmia), chest pain (acute coronary syndrome), shortness of breath (e.g. heart failure)
  • Respiratory: dyspnoea, cough (e.g. pneumonia), pleuritic chest pain (e.g. pulmonary embolism)
  • Gastrointestinal: diarrhoea, vomiting (e.g. dehydration/hypotension)
  • Genitourinary: oliguria (e.g. dehydration/hypotension)
  • Musculoskeletal: trauma (e.g. secondary to syncope)
  • Dermatological: rashes (e.g. meningococcal sepsis)
• Social Hx
  • Determine risk if they have subsequent syncopal episodes

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Red Flags

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• Exam
  • A→E
• Diagnostic approach
  • Can remember the categories using SNAP:

    • Structural and arrhythmic syncope are potentially life-threatening

      • Arrhythmic syncope
        • Bradyarrhthmias (e.g. sick sinus syndrome, 2° AV block, 3° AV block)
        • Tachyarrhythmias (SVT (e.g. AF AVNRT) or VT)
      • Structural syncope (∵ of mechanical obstruction to LV inflow or outflow)

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    • Neurally mediated and postural syncope are both typically benign (although they can have more serious underlying causes)

  • Can remember specific aetiologies
  • Mnemonic: HEAD, HEART, VESSELS

HealthPathways

<aside> ⚠️ Don’t request Holter monitoring, carotid duplex scans, echocardiography, electroencephalograms (EEGs) or telemetry in patients with first presentation of uncomplicated syncope and no high risk features

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• Patients may also report lightheadedness, a feeling of warmth, diaphoresis, nausea, and visual blurring occasionally proceeding to blindness

Sources:

• Talley O’Connor
• Geeky medics
• Emergency Care Institute