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.