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By far the most common cause of transient loss of consciousness in young subjects is a reflex syncopal event and in particular a vasovagal faint [1,2]. A variety of triggers have been identified [Table 1]. | By far the most common cause of transient loss of consciousness in young subjects is a reflex syncopal event and in particular a vasovagal faint [1,2]. A variety of triggers have been identified [Table 1]. | ||
{| class="wikitable" border="0" style= | {| class="wikitable" border="0" style="width: 55%" | ||
|- align='left' | |- align='left' | ||
!Table 1. Classification of syncope based on triggers<br /> | !colspan="2" | Table 1. Classification of syncope based on triggers<br /> | ||
|- align='left' | |- align='left' | ||
!A) Reflex mediated Vasovagal syncope | |||
A) Reflex | !B) Mechanical/hydraulic factors | ||
Vasovagal syncope | |- align='left' valign="top" | ||
| Vasovagal syncope | |||
* emotionally induced e,g., venipunctures, immunizations, sight of blood) (central type) | * emotionally induced e,g., venipunctures, immunizations, sight of blood) (central type) | ||
* orthostatic induced (peripheral type) | * orthostatic induced (peripheral type) | ||
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* urogenital tract instrumentation | * urogenital tract instrumentation | ||
* pulmonary airway instrumentation | * pulmonary airway instrumentation | ||
| Initial orthostatic hypotension | |||
Initial orthostatic hypotension | |||
Increased intrathoracic pressure: cough and sneeeze syncope | Increased intrathoracic pressure: cough and sneeeze syncope | ||
* wind instrument player's syncope | * wind instrument player's syncope | ||
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|} | |} | ||
{| class="wikitable" border="0" style='float: | {| class="wikitable" border="0" style='float: right' | ||
|- align='left' | |- align='left' | ||
!Table 2:Typical Premonitory Symptoms for Reflex Syncope<br /> | !Table 2:Typical Premonitory Symptoms for Reflex Syncope<br /> | ||
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* Sweating, dilated pupils | * Sweating, dilated pupils | ||
|} | |} | ||
Two clinical scenarios in particular are known to provoke vasovagal faints in young subjects. First and foremost are the situations that increase pooling of venous blood below the heart, such as long periods of standing motionless, particularly in combination with elevated ambient temperatures. | |||
Young subjects often experience prodromal signs and symptoms when a spontaneous vasovagal syncope is imminent (Table 2) [1,2]. | |||
{{case_present| | {{case_present| | ||
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[[File:Figure1.jpg | Frequency of the complaint fainting as reason for encounter in general practice in the Netherlands. Data are obtained from the general practitioners transition project. It concerns an analysis of 93.297 patient years. The arrow around 1 year is to indicate that a small peak occurs between 6-18 months (breath-holding spells). [From Colman et al reference 7 with permission]]] | [[File:Figure1.jpg | Frequency of the complaint fainting as reason for encounter in general practice in the Netherlands. Data are obtained from the general practitioners transition project. It concerns an analysis of 93.297 patient years. The arrow around 1 year is to indicate that a small peak occurs between 6-18 months (breath-holding spells). [From Colman et al reference 7 with permission]]] | ||
{{case_present| | |||
An incidence peak occurs around the age of 15 years, with females having more than twice the incidence of males [8]. | An incidence peak occurs around the age of 15 years, with females having more than twice the incidence of males [8]. | ||
Syncope is an infrequent occurrence in adults. The incidence of syncope progressively increases over the age of about 40 years to become high at in the older age groups. A lower peak occurs in older infants and toddlers, most commonly referred to as “breath-holding spells” | Syncope is an infrequent occurrence in adults. The incidence of syncope progressively increases over the age of about 40 years to become high at in the older age groups. A lower peak occurs in older infants and toddlers, most commonly referred to as “breath-holding spells” | ||
The incidence of syncope in young subjects coming to medical attention varies from approximately 0.5 to 3 cases per 1000 (0.05 – 0.3%) [9]. Syncopal events which do not reach medical attention occur much more frequently. In fact, the recently published results of a survey of students averaging 20 years of age demonstrated that about 20% of male and 50% of females report to have experienced at least one syncopal episode [8]. By comparison, the prevalence of epileptic seizures in a similar age group is about 5 per 1000 (0.5%) [10] and cardiac syncope (i.e., cardiac arrhythmias or structural heart disease) is even far less common [1,7]. | The incidence of syncope in young subjects coming to medical attention varies from approximately 0.5 to 3 cases per 1000 (0.05 – 0.3%) [9]. Syncopal events which do not reach medical attention occur much more frequently. In fact, the recently published results of a survey of students averaging 20 years of age demonstrated that about 20% of male and 50% of females report to have experienced at least one syncopal episode [8]. By comparison, the prevalence of epileptic seizures in a similar age group is about 5 per 1000 (0.5%) [10] and cardiac syncope (i.e., cardiac arrhythmias or structural heart disease) is even far less common [1,7]. | ||
}} | |||
== References == | == References == |
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