Syncope is synonym to: Fainting. It is a  loss of consciousness and postural tone as a result of diminished cerebral blood flow. It may be due to vaso-vagal attack or Cardiac causes.

It may result from Prolonged standing, severe emotional disturbance, site of blood (e.g. witnessed by medical student for the first time in theatre).

The more severe form is associated with various heart diseases:

  • Arrhythmias (especially complete heart block)
  • Hypertrophic cardiomyopathy
  • ‘Heart attack’ (mycardial infarction)
  • Atrial myxoma
  • Aortic stenosis
  • Dissecting aneurysm other causes:
  • Pulmonary embolism Vertebro-basilar insufficiency
  • Subclavian steal syndromCarotid sinus pressurMigraine headache

Clinical features

  • Sudden fall to the ground with loss of consciousness
  • Cold extremities
  • Bluish discolouration of extremities (cyanosis)
  • Pulse irregularities (or pulselessness)
  • Hypotension (or unrecordable blood pressure)
  • Fainting induced by pressure on the neck
  • Fainting induced by coughing, micturition

Differential diagnoses

  • Epilepsy
  • Myocardial infarction
  • Stroke
  • Aortic dissection
  • Hysteria


  • Cerebral hypoxia/anoxia resulting in brain damage
  • Stroke
  • Sudden death


  • Electrocardiography
  • Echocardiography
  • Neuro-imaging: CT scan, MRI, carotid
  • Doppler
  • Random blood sugar.


Depends on the cause(s)

Treatment objectives

  • Restore circulation and ensure brain perfusion by elevating the legs to increasebvenous return
  • Identify cause and treat
  • Prevent recurrence

Non-drug treatment

  • Physiotherapy: pressure stockings

Drug treatment

  • Specific treatment for cardiac arrhythmias:
  • refer to cardiologist
  • If hypotensive, give pressor agents

Notable adverse drug reactions, caution

  • Aspirin and other NSAIDs: use with
    caution in patients with history of dyspepsia, and in asthmatics


  • Avoid prolonged standing
  • Treat underlying cardiac disease
  • Avoid dehydration or excessive fluid loss
  • Use medication as prescribed by physicians and avoid overdosage to compensate for missed doses
  • Ensure adequate calorie and avoid prolonged fasting

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