Syncope



Syncope


Sanjay Mehta



Introduction



  • Syncope is defined as temporary loss of consciousness and postural tone due to an abrupt, transient, and diffuse reversible disturbance of cerebral function


  • Usually a benign isolated event, fairly common



    • Incidence 0.1-0.5% of children, 1-3% of emergency visits


    • Peaks in adolescents, females > males


  • Usually benign, requiring minimal investigation, but may be a result of potentially life-threatening causes


Loss of Consciousness: Differential Diagnosis



  • True syncope



    • Transient, acute loss of consciousness caused by a decreased cerebral blood flow secondary to vasodilation or decreased cardiac output


  • Neurologic



    • Seizures, migraines


  • Hysterical



    • Pseudoloss of consciousness


Common Causes of True Syncope



  • Vasovagal


  • Orthostatic


  • Hyperventilation


  • Breath-holding


Vasovagal Syncope (“Simple Faint”)



  • Common in teenage females


  • 50% of childhood syncope


  • Altered systemic vascular tone due to exaggerated Bezold-Jarisch reflex: responsible for maintaining blood pressure on standing



  • Vasodilation and vagally mediated bradycardia


  • Rapid drop in BP and bradycardia, nausea, vomiting, sweating, pallor, numbness, blurred vision, weakness








Table 22.1 Classification

































Neural-mediated syncope (NMS)

Vasovagal

Reflex (breath-holding, cough, micturition)

Hyperventilation


Orthostatic

Blood or fluid loss


Cardiovascular

Arrhythmias

Congenital heart disease

Cardiomyopathy


Metabolic

Hypoglycemia


Hypoxic

Carbon monoxide


Neurologic

Syncopal migraine (rare; basilar artery most common)


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Jun 22, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Syncope

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