Definition Syncope is a transient loss of consciousness associated with inability to maintain postural tone followed by rapid and spontaneous recovery. (1)
Epidemiology About 30-50% of children have syncope at least once in their lives till adolescent period, most of them are girls, 9% is the rate of syncope in 15-17 years old adolescent group, and this rate increase to the end of adolescent period. (2)
Causes (3)
I_Neurally mediated syncope
Neurocardiogenic (vasovagal)
- Emotional stress induced (pain, fear, blood phobia, etc.)
- Orthostatic stress induced
Situational syncope
- Respiratory (cough, sneeze, laugh, head turning)
- Gastrointestinal stimulation (swallowing, defecation, postprandial)
- Post micturition
- Post exercise
- Others
Carotid sinus syncope
Glossopharyngeal and trigeminal neuralgia syncope II_Cardiogenic syncope
- Arrhythmias as Bradycardia: - sinus node dysfunction (including bradycardia/tachycardia syndrome) - atrioventricular conduction system disease Tachycardia: - supraventricular - ventricular
- Structural heart defects as acute myocardial infarction/ischaemia, hypertrophic cardiomyopathy, cardiac masses (atrial myxoma, tumours, etc.), pericardial disease /tamponade.
- Functional heart defects as prosthetic valve dysfunction, pulmonary hypertension.
- Vascular heart abnormalities as aortic stenosis, congenital anomalies of coronary arteries, pulmonary embolus, acute aortic dissection.
III_ Orthostatic hypotensive syncope
- Primary autonomic disorder
- Secondary autonomic disorder
- Drug-induced orthostatic hypotension
- Hypovolemia related IV_Postural orthostatic tachycardia syndrome V_Metabolic reasons of syncope
- Hypoglycemia
- Hypoxia
- Electrolyte imbalance VI_Psychogenic syncope
- Anxiety
- Panic attack
- Depression
- Somatization VII_Drug-induced syncope
- Antihypertensives, diuretics, barbiturates, tricyclic antidepressants, alcohol, antiarrhythmics, macrolides, antihistamines, antipsychotics, MAO inhibitors, levodopa, prazosin, benzodiazepines VIII_Airway obstruction induced syncope IX_Hyperventilation-induced syncope X_Neurologic Syncope
- Cerebrovascular diseases
- Increased intracranial pressure
- Migraine
Symptoms
- The prodrome is the most important aspect of the history.
- A warm or clammy sensation, nausea, light headedness or visual changes (e.g seeing spots, grey out, tunneling)are strongly suggestive of vasovagal syndrome, other symptoms include irritability, confusion, auditory changes or dyspnea.
- The absence of prodrome raise the suspicion of a possible cardiac cause. 85%of children with vasovagal syncope has a prodrome, wheras only 40% of those with cardiac condition had a prodromal symptoms.
Palpitation and chest pain have been related to pediatric cardiac cause of syncope.(4) vasovagal syncope might also produce complex movement which raise a suspicion of epilepsy.(5)
- Most syncope is vasovagal, which is benign and doesn't require extensive investigation. The position statement presents recommendation to encourage an efficient and cost effective deposition for the many patients with a benign cause of syncope and hightlight atypical or concerning clinical findings associated with other causes of transient loss of consciousness.
- The prodrome and cirumstances around which the event occurred are the most important aspect of the history.
- Syncope occurring midexertion suggest cardiac etiology. A family history includes sudden death in the young or from unknown causes or causes that might be suspected to be other than natural can be a red flag.
- ECG is the most frequently ordered test, but the yield is low, It's recommended when patient's history isn't suggestive of vasovagal syncope and other features suggestive of cardiac cause like absence of prodrome, midexertion and family history of early life sudden death or heart diseases, abnormal physical examination or a new medication with potential cardiac cardiotoxicity.(6)