Syncope is defined as a temporary loss of consciousness related to a reduction in perfusion to the brain. Syncope may be considered a common medical problem with approx 3-5% of all hospital presentations related to the syncopal event.1
Syncope may be attributed to a number of different causes that range from benign to life-threatening cardiac conditions. The total cost of undiagnosed syncope is considerable and patients may present several times per year (to GP’s/ ED’s) and can affect the quality of life for patients with frequent episodes.
A detailed history to uncover the presence or absence of any prodrome, activities undertaken at the time of the syncopal event and identifying important cardiac causes can be a vital key to determining between benign or significant cardiac syncope.
The causes of syncope can be divided into:
Metabolic causes include:
Psychiatric causes include:
Neurological causes include:
Neurally mediated syncope- may be more common in children and young adults. This syndrome may include carotid sinus syndrome, situational syncope and neurocardiogenic (or vasovagal syncope).
This may be characterized by a systemic episode of hypotension that cab present with very slow heart rates and systemic vasodilation. The mechanism of this type of syncope is complex and is thought to involve reflex mediated alterations to heart rate and vascular tone.
Neurocardiogenic syncope may present similarly to other forms of syncope, such as a temporising loss of consciousness but may also present with a prodrome such (but not limited to):