Syncope

Question 1

Definition

Answer 1

Transient loss of consciousness due to inadequate cerebral blood flow.

Question 2

Aetiology

Answer 2

Cardiovascular causes:
– vascular:
—- neurocardiogenic (vasovagal attack)- a simple faint, most common cause of syncope, peripheral vasodilation and venous pooling of blood causes the heart to pump quicker, overall this causes a lower blood pressure

– postural hypotension (low blood pressure when standing from sitting or lying down)- reflex vasoconstriction usually prevents hypotension, if this is absence this can lead to hypotension.

– postprandial hypotension (hypotension after eating a meal) (drop of >20 mmHg)- if drops more than 20mmHg after eating within 2 hours, generally unknown why this happens.

– micturition syncope (fainting while or immediately after urinating)

Obstructive:
- all lead to restricted blood flow to the heart meaning there is less blood flow so less cerebral blood flow
— aortic stenosis
— hypertrophic cardiomyopathy
— pulmonary stenosis
— pulmonary embolism
— atrial thrombus
— defective prosthetic valve

Arrhythmia:
– rapid tachycardias
– profound bradycardias (Stokes-Adams attack)
– significant pauses in rhythm
– artificial pacemaker failure