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Syncope Evaluation

Key considerations: Seizure mimicking syncope, Cardiac arrhythmia causing syncope, Vertebrobasilar TIA

Cannot miss

  • Seizure mimicking syncope
  • Cardiac arrhythmia causing syncope
  • Vertebrobasilar TIA
  • Subclavian steal syndrome

Likely diagnoses

  • Vasovagal syncope
  • Orthostatic hypotension
  • Cardiac arrhythmia
  • Situational syncope
  • Carotid sinus hypersensitivity

Red flags

  • Syncope during exertion (cardiac cause)
  • Syncope with chest pain
  • Syncope in supine position (not vasovagal)
  • No prodrome
  • Family history of sudden cardiac death
  • Focal neurologic findings post-event
  • Age >60 with first syncope

Workup

  • history: Prodrome, position, activity at onset, witnesses, post-event confusion duration, medications, family history; exam: Orthostatic vital signs, cardiac auscultation (murmurs), carotid bruits, neurologic exam; labs: ECG (mandatory in all), glucose, CBC, BMP, troponin if cardiac concern; imaging: Head CT only if focal findings or head trauma; Echocardiogram if structural heart disease suspected; bedside: Orthostatic vitals, ECG, cardiac monitoring

Management

  • immediate: Treat underlying cause if identified; general: Vasovagal: education, avoid triggers, increase salt/fluid, compression stockings, fludrocortisone if refractory; Orthostatic: volume repletion, medication review, compression garments, midodrine; Cardiac: cardiology referral, pacemaker or ICD as indicated; Tilt-table test for recurrent unexplained syncope

Disposition

  • admit: High-risk features per Canadian Syncope Risk Score, abnormal ECG, cardiac syncope suspected; discharge: Low risk with clear vasovagal etiology and outpatient follow-up; consults: Cardiology if cardiac cause suspected, neurology if seizure suspected

Clinical pearls

  • Tongue biting (lateral tongue, not tip), prolonged post-ictal confusion (>5 min), and witnessed tonic-clonic activity point toward seizure rather than syncope
  • Brief myoclonic jerks CAN occur with syncope — do not mistake for epileptic seizures
  • Canadian Syncope Risk Score effectively risk-stratifies ED syncope patients

Source and review

  • ESC Syncope Guidelines 2018. Last reviewed: 2024-11-01