History: LOC Flashcards
What are the 3 major criteria for syncope?
1) Loss of consciousness: an initial loss of postural tone (going floppy) is a good indication of this.
2) LOC must be transient (i.e. self-limiting - excludes events such as cardiac arrest and hypoglycaemic coma which do not normally involve spontaneous recover)
3) Caused by global cerebral hypoperfusion, which almost always means a reduction in blood pressure.
What characteristics point to a syncopal episodes?
- rapid onset
- short duration (typically <20 seconds)
- spontaneous and complete recovery (although some disorientation is common with increasing age)
Questions to ask about ‘before’ the syncopal event ?
1) Triggers e.g. emotion, pain, exercise
2) Prodrome/’pre-syncope’ e.g. light-headed, dizzy, vertigo, nausea, sweating, tinnitus, visual disturbances
3) Change colour - pallor (occurs from systemic hypotension)
4) Any concurrent illnesses or infections
5) What were they doing before?
What does the presence of palpitations or other cardiac symptoms prior to syncope indicate?
A cardiac cause of syncope
What does cyanosis prior to LOC indicate?
A blue colour (cyanosis) occurs from transient loss of respiratory muscle action in any seizure beginning with a tonic phase (e.g. generalised tonic-clonic seizure).
Questions to ask about ‘during’ the syncopal event ?
1) Was it witnessed?
2) Do they remember falling?
3) How long did LOC last?
4) Was there a convulsion?
5) Tongue biting or incontinence?
Questions to ask about ‘after’ the syncopal event ?
1) Who found them?
2) How did they get up/get to doctors?
3) Length of LOC?
4) Length of lie?
5) How long did it take for full recovery?
6) Confusion or drowsiness?
7) Pain or injuries (ask about head trauma, especially if on blood thinners)
What is reflex syncope?
A general term used to describe types of syncope resulting from a failure in autoregulation of blood pressure, and ultimately, in cerebral perfusion pressure resulting in transient LOC.
E.g. Vasovagal syncope, situational syncope, carotid sinus hypersensitivity.
What are 2 triggers for vasovagal syncope?
1) Emotional distress (e.g. fear, pain, instrumentation, blood phobia)
2) Orthostatic stress (e.g. prolonged standing).
What are some triggers for situational syncope?
Cough, sneeze, defecation, micturition, exercise and eating (post-prandial).
What are some triggers for carotid sinus hypersensitivity?
Shaving, tight-fitting collars and sudden turning of the head.
What is LOC triggered by physical exertion often associated with?
CVS syncope e.g. aortic stenosis, arrhytmia
What is LOC triggered by going from sitting to standing often associated with?
orthostatic hypotension (e.g. hypovolaemia, autonomic failure).
What is LOC triggered by working with arms elevated about head often associated with?
subclavian steal syndrome
What is subclavian steal syndrome?
A rare condition causing syncope or neurological deficits when the blood supply to the affected arm is increased through exercise.
Subclavian steal is 2ary to a proximal stenosing lesion or occlusion in the subclavian artery, typically on the left.
Vasovagal syncope is often preceded by prodromal symptoms.
Give some examples
1) Progressive light-headedness
2) Visual disturbances (dimming of vision or loss of vision)
3) Weakness or sensory disturbances of the extremities
4) Sweating
5) Nausea
6) Tinnitus
Describe fall in vasovagal syncope vs CVS syncope
Vasovagal - patient typically demonstrates a slow, controlled collapse towards the ground
CVS - involves a sudden uncontrolled fall to the ground
Prodromal symptoms in CVS syncope vs vasovagal syncope?
CVS syncope often lacks any prodromal symptoms, with the patient feeling ok and then losing consciousness suddenly with no warning.
CVS syncope may cause cardiac symptoms prior e.g. palpitations, chest pain (2ary to arrhythmia).
Generalised seizures can begin with epileptic auras or focal motor/sensory seizures.
What symptoms can this cause?
- Olfactory or gustatory hallucinations (e.g. a specific smell or taste)
- Visual hallucinations (e.g. flashing lights or blurring of vision)
- A sense of déjà-vu
- Sensory disturbances (e.g. numbness, tingling)
- Motor weakness (e.g. unilateral limb weakness, twitching)
Once it has been established syncope has occurred, there are two important aims for further assessment.
What are they?
1) Determine the underlying cause, in the hope of providing treatment and preventing further events
2) Ascertain their risk of further events
What are the 4 classifications of syncope?
1) Structural (potentially life-threatening)
2) Arrhythmic (potentially life-threatening)
3) Neurally mediated (typically benign)
4) Postural (typically benign)
Use mneumonic - SNAP.
What is neurally mediated syncope?
Due to an inappropriate autonomic reflex in response to a trigger (also known as reflex syncope).
What is the most common type of syncope?
Vasovagal
What are the 3 types of neurally mediated syncope?
1) Vasovagal
2) Situational
3) Carotid sinus hypersensitivity
What type of situational syncope is a red flag?
Post-exercise syncope - must be investigated further to rule out a structural cardiac cause
Causes of vagovagal syncope?
It is common in young people following emotional response, such as fear, anxiety or disgust, but may also happen due to prolonged standing.