Syncope can be defined as a transient loss of consciousness due to a short lived global cerebral hypoperfusion. It has a rapid onset, short duration and spontaneous and complete recovery.

Epidemiology:

• Syncope is common and 15-20% of children will have experienced at least one episode by the age of 18.
• Peak incidence is in 15-19 year olds, most are benign and it is more common in females.

Differential diagnosis

• Reflex (neural mediated)
  • Vasovagal (common faint)
  • Situational (Cough, post-micturition)
  • Breath holding
  • Reflex anoxic seizures
• Cardiac - electrical (arrhthmias)
  • Brady - AV block
  • Tachy - VT, SVT
  • long/short QT
  • Brugada syndrome
  • CPVT
• Cardiac - structural
  • Aortic stenosis
  • HOCM
  • Pulm HTN
  • Congenital abnormalities
  • Coronary artery abnormalities
• Non-cardiovascular
  • Neurological
  • Psychogenic
  • Metabolic - e.g. hypoglycaemia
• Orthostatic
  • Drug induced
  • Autonomic

Syncope mimics:

• Seizure
• Migraine syndromes
• Hyperventilation
• Acute intoxication - e.g. alcohol
• hypoglycaemia