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==Epidemiology of neurally mediated syncope==
==Epidemiology of neurally mediated syncope==


The prevalence of syncope in the general population is ''extremely'' common. Almost everybody seems to have either experienced or witnessed an episode. Syncopal events often do not reach medical attention, particularly in the young in whom most episodes are considered to be innocent neurally mediated events (Soteriades et al., 2002;Wieling et al., 2004b).
The prevalence of syncope in the general population is ''extremely'' common. Almost everybody seems to have either experienced or witnessed an episode. Syncopal events often do not reach medical attention, particularly in the young in whom most episodes are considered to be innocent neurally mediated events<cite>1</cite>,<cite>2<cite>.


Studies in young populations show a strikingly high incidence of syncope. Two recent surveys of the frequency of syncope in medical students demonstrated that ''20-25% of males and 40-50% of females'' report to have experienced at least one such episode (Ganzeboom et al., 2003;Serletis et al., 2006). The majority of the syncope triggers identified in these students involved stresses or conditions that affect orthostatic blood pressure control. Neurally mediated syncope was therefore a likely cause of the symptoms in these young subjects. The incidence peak of presumed neurally mediated syncope around the age of 15 years and the much higher incidence in young females is a consistent finding (fig. 1)(Ganzeboom et al., 2003;Colman et al., 2004a;Ganzeboom et al., 2006;Serletis et al., 2006;Sheldon et al., 2006).  A family history of presumed neurally mediated syncope in the first degree relatives is often present in young fainting subjects (Mathias et al., 1998;Serletis et al., 2006).  
Studies in young populations show a strikingly high incidence of syncope. Two recent surveys of the frequency of syncope in medical students demonstrated that ''20-25% of males and 40-50% of females'' report to have experienced at least one such episode (Ganzeboom et al., 2003;Serletis et al., 2006). The majority of the syncope triggers identified in these students involved stresses or conditions that affect orthostatic blood pressure control. Neurally mediated syncope was therefore a likely cause of the symptoms in these young subjects. The incidence peak of presumed neurally mediated syncope around the age of 15 years and the much higher incidence in young females is a consistent finding (fig. 1)(Ganzeboom et al., 2003;Colman et al., 2004a;Ganzeboom et al., 2006;Serletis et al., 2006;Sheldon et al., 2006).  A family history of presumed neurally mediated syncope in the first degree relatives is often present in young fainting subjects (Mathias et al., 1998;Serletis et al., 2006).  
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==Influence of age==
==Influence of age==


A first neurally mediated syncopal episode  is rare in adults aged 35-60 years. About 80% of the syncope patients in this age group have experienced presumed neurally mediated episodes as teenagers and adolescents, which may of help in establishing a diagnosis (Ganzeboom et al., 2006, Serletis et al 2006).
A first neurally mediated syncopal episode  is rare in adults aged 35-60 years. About 80% of the syncope patients in this age group have experienced presumed neurally mediated episodes as teenagers and adolescents, which may of help in establishing a diagnosis <cite>Ganzeboom</cite>,<cite>Serletis</cite>.


Patients with presumed neurally mediated syncope present themselves to general practitioners according to a bimodal age distribution (fig. 2) with a first peak at the age of 15 years, and a second peak in ollder adults and elderly (Colman et al., 2004a).
Patients with presumed neurally mediated syncope present themselves to general practitioners according to a bimodal age distribution (fig. 2) with a first peak at the age of 15 years, and a second peak in ollder adults and elderly <cite>Colman</cite>.
~Figure 2~
~Figure 2~
Typical [[vasovagal syncope]] is less common in these older subjects. It is not unusual that the episodes of [[vasovagal syncope]] an older patient experiences are far les typical than [[vasovagal syncope]] at younger age. Thus, neurally mediated syncope may  be considered as a chronic life long condition, with different clinical presentation and triggers among episodes (Kurbaan et al., 2003;Colman et al., 2004a;Sheldon et al., 2006).  
Typical [[vasovagal syncope]] is less common in these older subjects. It is not unusual that the episodes of [[vasovagal syncope]] an older patient experiences are far les typical than [[vasovagal syncope]] at younger age. Thus, neurally mediated syncope may  be considered as a chronic life long condition, with different clinical presentation and triggers among episodes <cite>Kurbaan</cite>,<cite>Colman</cite>,<cite>Sheldon</cite>.  
    
    
In older subjects cardiac causes of syncope, [[orthostatic hypotension|orthostatic]] and postprandial hypotension and carotid sinus hypersensitivity  are more frequent (Kapoor, 1994;Youde et al., 2000;Mukai & Lipsitz, 2002). This can be attributed to diminished efficiency of cardiovascular regulatory systems, to medication affecting orthostatic blood pressure control and to increased prevalence of organic disease (e.g. structural heart disease, cardiac arrhythmia’s (Brady & Shen, 1999).  In the elderly, multiple causes of syncope are often present and the medical history may be less reliable than in the young, for example syncope may be erroneously reported as a fall (McIntosh et al., 1993;Kapoor, 1994;Benke et al., 1997;Kenny, 2003)
In older subjects [[Cardiac syncope|cardiac causes]] of syncope, [[orthostatic hypotension|orthostatic]] and postprandial hypotension and [[Carotid sinus hypersensitivity|carotid sinus hypersensitivity]] are more frequent <cite>Kapoor</cite>,<cite>Youde</cite>,<cite>Mukai & Lipsitz</cite>. This can be attributed to diminished efficiency of cardiovascular regulatory systems, to medication affecting orthostatic blood pressure control and to increased prevalence of organic disease (e.g. structural heart disease, cardiac arrhythmia’s <cite>Brady</cite>.  In the elderly, multiple causes of syncope are often present and the medical history may be less reliable than in the young, for example syncope may be erroneously reported as a fall <cite>McIntosh</cite>,<cite>Kapoor</cite>,<cite>Benke</cite>,<cite>Kenny</cite>.
 
==References==
<biblio>
#1 pmid=12239256
#2 pmid=15310717
#Ganzeboom pmid=12686351
#Serletis pmid=16837484
#Colman pmid=15480937
#Sheldon pmid=16223744
#Kurbaan pmid=12651049
#Kapoor pmid=8144829
#Youde pmid=10894317
#Mukai & Lipsitz pmid=12180246
#Brady pmid=11416498
#McIntosh pmid=8438668
#Benke pmid=9018029
#Kenny pmid=12950524
</biblio>

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