Vasovagal syncope

Question 1

What is vasovagal syncope?

Answer 1

LOC due to reflex bradycardia +/- peripheral vasodilation provoked by emotion, pain or standing too long.

Question 2

What is the physiology behind vasovagal syncope?

Answer 2

The vagus nerve discharge decreases blood flow to the brain (parasympathetic activation).

Question 3

Give some examples of things that stimulate syncope

Answer 3

1. Strong emotion (fear, pain, blood phobia)
2. Orthostatic stress (prolonged standing, hot weather)

Question 4

Describe the symptoms of syncope

Answer 4

• LOC that is over in seconds
• Vagal symptoms like nausea, swaeting, pallor and narrowing of visual fields may precede LOC
• Brief tonic-clonic jerking may occue during blackout due to cerebral hypoperfusion
• Recovery is QUICK

Question 5

State further investigations for syncope patient

Answer 5

• Cardiac assessment; ECG to identify heart block or arrhythmia
• Bloods- FBC; glucose (check for hypoglycaemia); U&E
• CT/ MRI of brain and neuro assessments
• Lying and standing blood pressure- check for orthostatic hypotension

Question 6

What is orthostatic hypotension

Answer 6

impaired vasomotor reflexes from lying to standing up; can be due to autonomic neuropathy and antihypertensive medication.