Syncope is defined as a loss of consciousness or muscle tone.  Approximately 15% of children have a history of syncope and the majority of cases are benign.  The pathophysiology is thought to be a result of decreased blood flow to the brain and frequently the individuals will experience some light-headedness or dizziness prior to the syncopal episode.  There is a high rate of recurrences and if specific causes are found, treatment is effective in preventing episodes.

Etiology
1. Cardiac
     a. outflow obstruction ( Aortic stenosis and hypertrophic cardiomyopathy)
     b. Arrhythmia
     c. Myopathy or ischemia (coronary artery disease)

2. Non-Cardiac
    a. Seizures
    b. migraines
     c. Orthostatic hypotension
     d. psychogenic
     e. Breath holding spells
     f. hypoglycemia and electrolyte disturbances
     g. Endocrine disorders
     i. Carbon Monoxide poisoning

3. Vasovagal
     a. fear
     b. Panic and anxiety
     c. Standing for a long period of time.

Evaluation
1. History- must be provided by the patient and an observer of the event
     a. preceding event
     b. Was it associated with exercise- often suggests cardiac etiology and risk of  sudden death
     c. Loss of consciousness, incontinence, how patient felt afterwards, post ictal
     d. Family history- seizures, migraine, sudden death, EKG abnormalities
     e. Palpitations
     f. History of similar episodes
     g. Emotional state- stress in life
     h. Drug use
     i. Pregnancy

2. Physical Examination
     a. Vital signs
     b. Thorough cardiac examination

3. All unexplained episodes must include cardiac evaluation including echocardiography, EKG, Holter monitor,    Stress testing

4. EEG and possible neuroimaging if history consistent with seizures.

5. Tilt table test

Management
1. If there is an arrhythmia, medications or ablation surgery
2. Breath holding spells- need to reassure parents and avoid if possible precipitating events
3. Migraines- medications
4. Seizures- medications
5. Hysteria- psychiatric evaluation
6, Vagovagal
     a. avoid activity
     b. Contracting leg muscles intermittently when standing still
     c. Interrupt activity and lie down before loss of consciousness
     d. Elastic hose may improve venous return to the heart
     e. Stay hydrated

References
1. Willis John. Syncope  Pediatrics in Review Vol 21 No. 6 June 2000
2. Hardy Christian Syncope and chest pain: To worry, or not?  Contemporary Pediatrics July 1994
3. Soteriades E.S. Incidence and Prognosis of Syncope.  NEJM Vol 347 No. 12 Sept 19 2002 Page 878
4. Grubb B. Neurogenic Syncope.  NEJM March 10, 2005
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