Vasovagal syncope Flashcards
Neurally mediated reflex syncope definition
Group of conditions where hypotension occurs as a result of neural reflex vasodilation and/or bradycardia and comprises:
- Vasovagal syncope (common faint)
- Carotid sinus syncope
- Situational faint
Epidemiology
Age: young Px and the elderly
Sex: more common in females
Triggers: emotion or prolonged standing
Pathophysiology
Cardiovascular reflexes that normally maintain circulation become transiently impaired in response to a trigger e.g. emotional stress
- Parasympathetic hyperactivity (bradycardia) +/or sympathetic hypoactivity (loss of vasocontrictor tone) = decrease in cardiac output
Triggers
Emotional stress:
- Fear
- Pain
- Blood phobia
Orthostatic stress:
- Prolonged standing
Triggers for situational syncope
Syncope associated with some specific circumstances
- Post exercise
- Micturition
- Cough
Carotid sinus syncope triggers
Increased carotid sinus sensitivity → pressure on the carotid sinuses (e.g., during a massage) triggers syncope
Pre-syncope signs
- Trigger e.g. prolonged standing
- Sweating
- Warmth
- Nausea
- Lightheadedness
- Diminished vision or hearing
- Pallor
- Hyperventilation
- Palpitations
Syncope signs
- Rapid onset loss of consciousness
- Usually lasts seconds to minutes with spontaneous and complete recovery
Diagnosis
Clinical diagnosis + suggestive by an absence of features to suggest alternative diagnosis such as cardiac syncope.
Consider:
- Lying/standing BP
- ECG
- FBC
- Blood glucose
- B-hCG
- Carotid sinus massage
Secondary care investigations for vasovagal syncope:
- Tilt table testing = for diagnostic uncertainty or recurrent symptoms
Treatment
FIRST LINE =
- Reassurance
- Education
- Tilt training = prlonged period of enforced upright prosture
- Counterpressure manoeuvres: e.g. leg crossing or hand grip and arm tensing = induce rise in bp
Second line:
- Medications = MIDODRINE (alpha-1-agonist) or fludrocortisone may be considered.
Complications
Trauma
