vasovagal syncope

Question 1

definition

Answer 1

Due to reflex bradycardia ± peripheral vasodilatation provoked by emotion, pain, fear or standing too long. Onset is over seconds (not instantaneous), and is often preceded by nausea, pallor, sweating and closing in of visual fields (pre-syncope). It cannot occur if lying down. He falls to the ground, being unconscious for ~2min. Brief clonic jerking of the limbs may occur (reflex anoxic convulsion due to cerebral hypoperfusion), but there is no stiffening or tonic/clonic sequence. Urinary incontinence is uncommon (but can occur), and there is no tongue-biting. Recovery is rapid (but not as quick as with a dysrhythmia).

Question 2

investigations

Answer 2

1st investigations

• 12 lead ECG
• serum Hb
• plasma blood glucose
• serum beta HCG
• cardiac enzymes
• d dimer
• serum cortisol (rule out adrenal insufficiency)
• urea or serum creatinine (rule out dehydration)

Question 3

causes

Answer 3

Prolonged standing esp. in warm surroundings, emotion
Other causes of vagal overactivity: micturition, cough, carotid sinus hypersensitivity
(e.g. on shaving the neck or head turning)
Metabolic: hypoglycaemia