Syncope: Difference between revisions
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==Epidemiology== | ==Epidemiology== | ||
Syncope is common in the general population. The life-time cumulative incidence of ≥1 syncopal episodes in teenagers in the general population is high, with about 40 % by the age of 21 years. Reflex syncope is by far the most common cause. The majority have experienced reflex-mediated syncope episodes as teenagers and adolescents. The frequency of cardiac syncope increases with age. Approximately 10-30% of the syncope episodes in patients above 60 years visiting a hospital for their syncope episodes are of cardiac origin. | Syncope is common in the general population. The life-time cumulative incidence of ≥1 syncopal episodes in teenagers in the general population is high, with about 40 % by the age of 21 years. Reflex syncope is by far the most common cause. The majority have experienced reflex-mediated syncope episodes as teenagers and adolescents. The frequency of orhtostatic hypotension and cardiac syncope increases with age. Approximately 10-30% of the syncope episodes in patients above 60 years visiting a hospital for their syncope episodes are of cardiac origin. | ||
==Reflex syncope== | ==Reflex syncope== | ||
===Diagnostic evaluation=== | ===Diagnostic evaluation=== | ||
Reflex syncope refers to a heterogeneous group of conditions in which there is a relatively sudden change in autonomic nervous system activity (decreased sympathic tonus causing less vasoconstriction and increased parasympathic (vagal) tonus causing bradycardia), triggered by a central (e.g. emotions, pain, blood phobia) or peripheral (e.g. prolonged orthostasis or increased carotid sinus afferent activity). It leads to a fall in blood pressure and cerebral perfusion. The range of bradycardia varies widely in reflex syncope, from a small reduction in peak heart rate to several seconds of asystole. As reflex syncope requires a reversal of the normal autonomic outflow, it usually occurs in people with a functional autonomic nervous system and should therfore be distinguished from syncope due to neurogenic orthostatic hypotension in patients with chronic autonomic failure. | |||
===Treatment=== | ===Treatment=== | ||
The prognosis of reflex syncope is excellent. | The prognosis of reflex syncope is excellent. However, syncope episodes can have a considerable impact on quality of life, because of its unexpected nature and fear for | ||
recurrences. Initial treatment of reflex syncope consists of non-pharmacological treatment measures, including reassurance regarding the benign nature of the condition, increasing the dietary salt and fluid intake, moderate exercise training, and physical counterpressure maneuvres (muscle tensing). | |||
==Orthostatic hypotension== | ==Orthostatic hypotension== | ||
===Diagnostic evaluation=== | ===Diagnostic evaluation=== | ||
===Treatment=== | ===Treatment=== | ||
==Cardiac syncope== | ==Cardiac syncope== | ||
===Diagnostic evaluation=== | ===Diagnostic evaluation=== | ||
===Treatment=== | ===Treatment=== | ||
Revision as of 18:01, 4 June 2011
 This website is currently being developed and in a testing phase. Content is incomplete and may be incorrect. |
Definition
Syncope is a transient loss of consciousness (TLOC) due to global cerebral hypoperfusion characterized by rapid onset, short duration and spontaneous complete recovery. This excludes other causes of TLOC such as neurological, psychological and metabolic causes.
Classification
Syncope can be classified into:
- Reflex syncope
- Vasovagal
- mediated by orthostatic or emotional stress
- Situational
- Cough
- Sneeze
- Gastro-intestinal (swallow, defaecation, visceral pain)
- Micturation
- Post-exercise
- Post-prandial
- Others (e.g. laugh, brass instrument playing, weightlifting)
- Carotid sinus syncope
- Atypical forms
- without apparent triggers and/or atypical presentation
- Vasovagal
- Syncope due to orthostatic hypotension
- Primary autonomic failure
- Pure autonomic failure
- Multiple system atrophy
- Parkinson's disease with autonomic failure
- Lewy body dementia
- Secondary autonomic failure
- Diabetes
- Amyloidosis
- Uraemia
- Spinal cord injuries
- Drug induced orthostatic hypotension
- Alcohol, vasodilators, diuretics, phenotiazines, antidepressants
- Volume depletion
- Haemorrhage, diarrhoea, vomiting etc.
- Primary autonomic failure
- Cardiac syncope
- Arrhythmias
- Bradycardia: sinus node dysfunction, atrio-ventricular conduction system disease, implanted device malfunction.
- Tachycardia: supraventricular, ventricular (idiopathic, secondary to structural heart disease or to channelopathies)
- Drug-induced arrhythmias
- Structural heart disease
- Cardiac: cardiac valvular disease (or prosthetic valve dysfunction), acute myocardial infarction/ischemia, hypertrophic cardiomyopathy, cardiac masses, pericardial disease/tamponade, congenital anomalies of coronary arteries
- Other: pulmonary embolus, acute aortic dissection, pulmonary hypertension
- Arrhythmias
Pathophysiology
(Figure pathophysiology syncope)
Epidemiology
Syncope is common in the general population. The life-time cumulative incidence of ≥1 syncopal episodes in teenagers in the general population is high, with about 40 % by the age of 21 years. Reflex syncope is by far the most common cause. The majority have experienced reflex-mediated syncope episodes as teenagers and adolescents. The frequency of orhtostatic hypotension and cardiac syncope increases with age. Approximately 10-30% of the syncope episodes in patients above 60 years visiting a hospital for their syncope episodes are of cardiac origin.
Reflex syncope
Diagnostic evaluation
Reflex syncope refers to a heterogeneous group of conditions in which there is a relatively sudden change in autonomic nervous system activity (decreased sympathic tonus causing less vasoconstriction and increased parasympathic (vagal) tonus causing bradycardia), triggered by a central (e.g. emotions, pain, blood phobia) or peripheral (e.g. prolonged orthostasis or increased carotid sinus afferent activity). It leads to a fall in blood pressure and cerebral perfusion. The range of bradycardia varies widely in reflex syncope, from a small reduction in peak heart rate to several seconds of asystole. As reflex syncope requires a reversal of the normal autonomic outflow, it usually occurs in people with a functional autonomic nervous system and should therfore be distinguished from syncope due to neurogenic orthostatic hypotension in patients with chronic autonomic failure.
Treatment
The prognosis of reflex syncope is excellent. However, syncope episodes can have a considerable impact on quality of life, because of its unexpected nature and fear for recurrences. Initial treatment of reflex syncope consists of non-pharmacological treatment measures, including reassurance regarding the benign nature of the condition, increasing the dietary salt and fluid intake, moderate exercise training, and physical counterpressure maneuvres (muscle tensing).