Syncope

When to Suspect:
  • Duration of LOC <30 secs.
  • Regains consciousness immediately; may feel sleepy or fatigued for several minutes, but is alert
  • Often a trigger (e.g. sight of blood) — see below
  • May include very brief tonic-clonic movements
  • Head trauma caused by faint might rarely confuse the picture

Causes of Syncope

Vasovagal syncope:
  • Emotional trigger (fear, pain, disgust, laughter, etc.)
  • Autonomic functions: cough, post-micturition, defecation, swallow (esp. cold liquid)
  • Valsalvas: weight-lifting, horn-playing, etc.
  • Situational: crowded room, prolonged standing, heat
  • Post-prandial, a combo of autonomic function plus circulatory steal (stomach from brain)
Orthostatic syncope:
  • Volume depletion
  • Medications / alcohol
  • Autonomic instability (diabetes, Parkinson’s, etc)
Cardiac syncope is due to Arrhythmias, which may be:
  • Benign: supraventricular tachycardia
  • Life-Threatening: heart block, ventricular tachycardia, long QT
Exertional syncope suggests Cardiac in a different way, either:
  • Coronary Artery disease (i.e. angina)
  • Outflow obstruction (hypertrophic cardiomyopathy, tumors, aortic stenosis)
Neck Movement causing syncope may be from either:
  • Carotid sinus pressure (vasovagal)
  • Aberrant carotid artery occlusion (causing a posterior-circulation TIA) [very rare]

Work-Up for Syncope

>   If Hx suggests Vasovagal or Orthostatic syncope: no tests
  • If frequent: Cardiol. referral (may do Tilt Table Testing)

>   Exertional Syncope:  EKG, Echocardiogram, ? Stress Test

>   Completely spontaneous syncope: EKG
  • Implantable Loop Recorder if recurrent faints
  • Cardiol referral if abnormal EKG
> Send to ER if:
  • Same-day exertional syncope
  • Same-day spontaneous syncope + abnormal EKG or cardiac risks

See postings LOC-1 and LOC-2.

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