Syncope Flashcards
describe TLCO
a state of real or apparent loss of consciousness with loss of awareness, characterised by amnesia for the period of unconsciousness, loss of motor control, loss of responsiveness and a short duration
list some causes of TLCO that need to be differentiated from syncope
head trauma
epileptic seizures
TLCO mimics (e.g. psychogenic pseudo-syncope, psychogenic pseudo-seizures)
other
careful history must be obtained from witness
provide a definition for syncope
specific form of TLCO
transient loss of consciousness due to cerebral hypoperfusion, characterised by rapid onset, short duration and spontaneous complete recovery
describe classifications of syncope
reflex syncope
orthostatic syncope
cardiac syncope
outline the pathophysiology of different types of syncope - reflex
preferred terminology of all types of syncope in which neural reflexes modify heart rate (cardioinhibition) and/or vascular tone (vasodepression) hence predisposing to a fall in MAP (systemic hypotension) of sufficient severity to affect cerebral perfusion causing a transient period of cerebral hypoperfusion resulting in syncope or near syncope
common
pathways for reflex activation not full understood
when activated, reflex causes cardioinhibition through vagal stimulation. This decreases heart rate (Bradycardia) and cardiac output (CO)
And/or vasodepression through depression of sympathetic activity to blood vessels. This decreases systemic vascular resistance (Vasodilatation), venous return, stroke volume and CO
The decrease in CO and SVR, decreases mean arterial blood pressure (MAP)
Results in cerebral hypoperfusion and syncope or near syncope
identify sub types of reflex syncope
vasovagal
situational
carotid sinus syncope
provide overview of treatment of different sub-types of reflex syncope - vasovagal
Treatment: education, reassurance, avoidance of triggers (if possible) and adequate hydration
describe vasovagal reflex syncope
most commonest type of syncope
Faint triggered by emotional distress (e.g. pain, fear, blood phobia) or orthostatic stress
associated with a typical prodrome (pallor, sweating, nausea)
Can be averted by e.g. adopting: horizontal gravity neutralisation position or leg crossing. These manoeuvres increase venous return
Main risk is the risk of injury when falling
not associated with increased mortality
describe situational reflex syncope
Faint during or immediately after a specific trigger e.g. cough, micturition, swallowing, etc.
Less common than vasovagal syncope
provide overview of treatment of different sub-types of reflex syncope - situational
Treat cause, if possible (e.g. cough)
Advise patient to lie down, if possible (e.g. during a coughing episode)
Avoid dehydration and excessive alcohol
Cardiac permanent pacing may be needed in some cases or situational syncope
describe carotid sinus reflex syncope
triggered by mechanical manipulation of the neck, shaving, tight collar, etc.
more common in elderly especially males
Other associated conditions such as carotid artery atherosclerosis may be found, but it is not clear if these are causative
may occur after head and neck surgery or radiation
provide overview of treatment of different sub-types of reflex syncope - carotid
Cardiac permanent pacing is generally recommended for CSS
describe postural hypotension
results from failure of baroreceptor responses to gravitational shifts in blood, when moving from horizontal to vertical position
describe risk factors of postural hypotension
age medications certain diseases reduced intravascular volume prolonged bed rest
describe cardiac syncope
caused by a cardiac event resulting in sudden drop in cardiac output;
Arrhythmias - resulting in bradycardia or tachycardia
Acute MI
Structural Cardiac Disease (e.g. aortic stenosis, hypertrophic cardiomyopathy)
Other Cardiovascular Disease (e.g. pulmonary embolism, aortic dissection)
