This document discusses syncope, which is a brief loss of consciousness due to decreased blood flow to the brain. It can be caused by cardiac issues like aortic stenosis or arrhythmias, neurological issues like carotid sinus hypersensitivity, orthostatic changes in blood pressure, psychiatric conditions, or certain medications. The evaluation of syncope involves taking a detailed history, performing a physical exam focusing on cardiovascular and neurological systems, doing tests like an ECG, labs, and tilt table testing, and considering imaging if needed to diagnose the underlying cause. Treatment depends on the identified cause but the goal is to prevent future episodes.

1. Syncope
Paleerat Jariyakanjana, MD
Faculty of Medicine, Naresuan University
7 Jun 2013

2.  composed of
 brief loss of consciousness
 inability to maintain postural tone
 spontaneously and completely resolves without
medical intervention
 distinct from vertigo, seizures, coma, and states
of altered consciousness

3. Epidemiology
 Near-syncope
 premonition of syncope without loss of
consciousness
 shares the same basic pathophysiologic process
as syncope and likely carries the same risks

4. ETIOLOGY

6. Cardiac-Related Syncope
Aortic stenosis
 excluded as a cause of syncope in the elderly
 classic presentation: chest pain, dyspnea on
exertion, and syncope

7. Cardiac-Related Syncope
Dysrhythmias
 occur because of a primary electrolyte
imbalance as in hypomagnesemia (torsades de
pointes)
 rarely occur in structurally normal hearts
 Exceptions: familial disorders of Brugada
syndrome, long QT syndrome, and
catecholamine-associated polymorphic
ventricular tachycardia
 typically sudden and usually without prodromal
symptoms

8. Vasovagal or Neurally/Reflex-
Mediated Syncope
Vasovagal syncope
 sensation of increased warmth
 preceding lightheadedness (prodrome) with
sweating and nausea
 slow, progressive onset with associated
prodrome

9. Vasovagal or Neurally/Reflex-
Mediated Syncope
Vasovagal syncope
 occur after exposure to an unexpected or
unpleasant sight, sound, smell, fear, severe
pain, emotional distress, and/or instrumentation
 occur in association with prolonged standing or
kneeling in a crowded or warm place or on
exertion
 Upright tilt table testing

10. Vasovagal or Neurally/Reflex-
Mediated Syncope
Carotid sinus hypersensitivity
 more common in men, the elderly, and among
those with ischemic heart
disease, hypertension, and certain head and
neck malignancies
 shaving or turning of the head
 considered in all older patients with recurrent
syncope and negative cardiac evaluations

11. Orthostatic Syncope
 Orthostatic blood pressures are recommended
to be taken after 5 minutes of being supine.
 Measurements are repeated after 1 and 3
minutes of standing.
 A decrease of >20 mm Hg in the systolic
pressure is considered abnormal as is a drop in
pressure below 90 mm Hg independent of the
development of symptoms.

12. Orthostatic Syncope
 intravascular volume loss
 dehydration or blood loss
 poor vascular tone
 α-receptor disorders or medications
 other life-threatening causes of syncope should
be considered before orthostasis is considered
the cause

13. Psychiatric Illness
 generalized anxiety disorder and major
depressive disorder
 Hyperventilation: lead to hypocarbia, cerebral
vasoconstriction, and subsequent syncope
 assigned only after organic causes have been
excluded

14. Medication-Induced Syncope

15. PRINCIPLES OF EVALUATION

16. History
 detailed description of the events preceding the
loss of consciousness
 FH: history of prolonged QT syndrome,
dysrhythmias, sudden cardiac death, or other
cardiac risks
Physical Examination
 Evidence of trauma
 focus on both cardiovascular and neurologic
systems

17. Diagnosis
 ECG
 Laboratory Testing
 Complete blood count, urine pregnancy test
 Carotid Massage
 Hyperventilation Maneuver
 Neurologic Testing
 CT scanning, electroencephalogram, or lumbar
puncture

18. DISPOSITION AND FOLLOW-
UP

22. POST-ED EVALUATION

24. Reference
 Tintinalli's Emergency Medicine, 7e

25. ANY QUESTIONS?