Blackout Flashcards
What are the divisions of syncopal causes of blackout
Reflex
Cardiac (reduced CO in arrhythmia, outlet obstruction)
Orthostatic
Cerebrovascular
What is reflex syncope
“primitive reflex”. HR and BP drops temporarily, reducing cerebral perfusion and leading to syncope. Some have a low threshold for activating this reflex in specific situations e.g. standing, being scared (blood, needles), straining (micturition, defacation)
What may cause orthostatic hypotension
Reduced intravascular volume (e.g. dehydration)
Normal autonomic response (transient tachycardia and peripheral vasoconstriction) or standing is blunted e.g. druggs or autonomic nueropathy
What are the reflex causes of blackouts
Vasovagal syncope
Carotid sinus hypersensitivity
Situational syncope e.g. micturition
What are the cardiac causes of blackout
Arrhythmias
Structural cardiac pathology causing outflow obstruction e.g. aortic stenosis, hypertrophic obstructive cardiomyopathy
What are the orthostatic causes of blackout
Drugs (anti-hypertensives, anti-sympathetics)
Dehydration
Autonomic instability
Baroreceptor dysfunction
What are the cerebrovascular causes of blackout
Vertebrobasilar insufficiency
Subclavian steal
Aortic dissection
What are the non-syncopal causes of blackout
Intoxication Head trauma Metabolic (hypoglycaemia) Psychogenic (non-epileptic_ seizures Narcolepsy
What is the main cause of loss of consciousness in a patient aged 25
Vasovagal syncope
Warning or presyncopal sensation (stomach, going pale, clammy)
What is the main cause of loss of consciousness in a patient aged 55
Vasovagal syncope and cardiac arrhythmias (usually secondary to IHD)
No warning, while playing sport or without trigger
What is the main cause of loss of consciousness in a patient aged 85
Orthostatic hypotension secondary to medications (diuretics, ACEi, beta blockers, CCBs)
Causes morbidity from broken bones, loss of consciousness and independence and mortality
What questions do you ask about before the loss of consciousness
Was there any warning
Were there any precipitating factors
Was there any recent head trauma
What does warning before the blackout tell you
no warning -> more likely cardiac cause e.g. arrhythmia, AS or cerebrovascular disease e.g. subclavian steal syndrome (although may be preceded by palpitations)
Most other blackout causes will have warning e.g. aura before epileptic seizure, dizziness before vasovagal
What does precipitating factors tell you about the loss of consciousness
Postural - orthostatic hypotension
Head turning - carotid sinus hypersensitivity
Sitting or lying down - arrhythmia
Exercise - primary cardiac pathology e.g. AS, cardiomyopathy
Vigorous arm activity - subclavian steal
What questions do you ask about during the loss of consciousness
How long were they unconscious for
Did they bite their tongue or move their limbs, or where they incontinent of urine or faeces
What does tongue biting or spasms during blackouts tell you
tongue-biting - epileptic seizure
twitching an incontinence - vasovagal or other
What questions do you ask about after the loss of consciousness
Did they recover spontaneously
How long did it take to recover if not
Were they confused
Summarise the before, during and after features of epilepsy
May have stereotyped aura before (partial) or none (general)
Can last minutes, same episodes every time, tongue biting
Slow recovery, confused for 5-30 minutes
Summarise the before, during and after features of Vasovagal attack
Vagal symptoms (sweating, pallor, nausea) may have precipitant
Last seconds, may twitch or be incontinent
Rapid recovery on sitting or lying
Summarise the before, during and after features of cardiac arrhythmias
No warning
Last seconds, may twitch or be incontinent
Rapid spontaneous recover
What is important to ask about in the past medical history for blackouts
Has it happened before Diabets Cardiac illness Peripheral vascular disease epilepsy Anaemia Psychiatric illness
What is important to ask about in the drug history for blackouts
insulin
Antihypertensives
Vasodilators
Antiarrhythmics
Antidepressants (SE of Tricyclic antidepressants)
Warfarin or anticoagulants (subdural haemorrhage>)
What is important to ask about in the social history for blackouts
Alcohol
Recreational drugs e.g. cocaine, amphetamines
What is important to ask about in the family history for blackouts
Sudden death in anyone <65 years of age
