Flashcards in Overview of physiology and pathophysiology of syncope Deck (34)
General explanation of syncope?
Specific form of a transient loss of consciousness
3 types of syncope?
Sub types of reflex syncope?
Carotid sinus (CCS)
Transient Loss of Consciousness (TLOC) definition?
A state of real or apparent loss of consciousness with loss of awareness, characterized by amnesia for the period of unconsciousness, loss of motor control, loss of responsiveness and a short duration.
What conditions can cause TLOC?
TLOC mimics (psychogenic, pseudo syncope)
Definition of syncope?
Transient loss of consciousness due to cerebral hypoperfusion, characterized by rapid onset, short duration and spontaneous complete recovery
All types of syncope in which neural reflexes modify HR and/or vascular tone (vasodepression) hence predisposing to a fall in MAP (sysetmic hypotension) of sufficient severity to affect cerebral perfusion causing a transient period of cerebral hypoperfusion resulting syncope or near syncope
Reflex syncope is uncommon. True or false?
False. It is common
Events that occur in reflex syncope?
When reflex is activated
this causes cardioinhibition through vagal stimulation
causing decreased HR and CO
Vasodepression through depression of sympathetic activity to blood vessels
Decreasing systemic vascular resistance (vasodilation), venous return, stroke volume and CO
This decreases in everything causes decrease in MAP
Cerebral hypoperfusion and syncope/ near syncope
Most common type of syncope?
What causes vasovagal syncope?
Faint is caused by emotional stress or orthostatic stress
What symptoms occur in vasovagal syncope?
How can vasovagal syncope be averted?
Lying down )adopting horizontal gravity neutralisation)
Both of these increase venous return
Main risk of Vasovagal syncope?
Injury when falling
VVS is not associated with increased mortality. True or false?
Treatment of VVS?
Avoidance of triggers
What happens in situational syncope?
Faint during or immediately after a specific trigger. Eg coughing, urination, swallowing
Vasovagal syncope is less common than situational syncope. True or false?
False. Vasovagal is most common
Treatment for situational syncope?
Treat the cause eg if it is a cough
Advise patient to lie down if possible
Avoid dehydration and XS alcohol
However some cases of cardiac pacing may be required in some cases
What is the carotid sinus reflex triggered by?
Mechanical manipulation of the neck eg shaving, tight collar
Who is CSS more common in?
When might CSS occur?
After head and neck surgery or radiation
Treatment of carotid sinus syncope?
Permanent pacing is generally recommended
Associated conditions with CSS?
Carotid artery atherosclerosis- not clear if this is causative or not
Another reason why people have syncope?
What is postural hypotension?
Results from failure of baroreceptor responses to gravitational shifts in blood, when moving from horizontal to vertical position
Other term for postural hypotension?
Risk factors for orthostatic hypotension?
Reduced intravascular disease
Prolonged bed rest
Positive result showing postural hypotension?
Drop in blood pressure within 3 minutes of standing up from lying position
Systolic= Atleast 20mmHg