Causes of Syncope
Head
|
- CVA / TIA
- Seizure
- Cancer
- Orthostatic hypotension
- Carotid stenosis
- Psychosis
|
Heart
|
- Myocardial infarction
- Arrhythmia
- tachycardia / bradycardia / Long QT Syndrome / Brugada Syndrome / WPW
- Aortic stenosis
- Obstructive cardiomyopathy
- Pacemaker malfunction
- Pericardial tamponade
|
Lungs
|
- Pulmonary Embolism
- Tension pneumothorax
|
Vessels
|
- Hypovolemia
- Toxins
- drugs / alcohol / Prescription Rx
- Electrolytes
- Ammonia (hepatic encephalopathy)
- Vasodilation
- sepsis / anaphylaxis / heat
- Aortic Dissection
- Ruptured AAA
- Anemia
- Vasovagal (neurocardiogenic)
- See Below
|
Vasovagal
Etiologies
(Neuro-cardiogenic)
|
- Carotid massage
- Defecation / Micturition
- Post-prandial
- Post-exercise
- Cough / sneeze
- Trumpet playing
- Weight lifting
- Prolonged standing
- Bezold-Jarisch Reflex
- pain / fright / emotion / blood loss / needles
- See Below
|
Bezold-Jarisch Reflex Explained Briefly
Common cause of Neuro-cardiogenic syncope (aka, vasovagal syncope)
**Adrenergic stimuli (pain/emotion)**
--> Exaggerated catecholamine release
↑ Sympathetic tone ++
↑ β1 contractility, before α1 can ↑preload
↑ Ventricular contraction on under-filled chamber
↑ Mechanoreceptor activation from exaggerated contractile force
--> Homeostatic vagal tone
↑ Vasodilation / Bradycardia ++
--> SYNCOPE
References
Kaye, GC. Arthur, W. The pathophysiology of common causes of syncope. Postgrad Med J2000;76:750-753. doi:10.1136/bmj.76.902.750
Brignole. M. Diagnosis and treatment of syncope. Heart. 2007 Jan; 93(1): 130–136. doi:10.1136/hrt.2005.080713