Approach to Syncope Flashcards
What is consciousness?
Awake person who is fully responsible to a thought/perception and indications by his speech/behavior the awareness of self/surroundings
How do you test for/confirm consciousness?
1) Response to external stimuli
- visual response
- verbal/non-verbal response correct for context/situation
- social response appropriate to context/situation
2) Memory/recall, high cognitive function
What are 3 physiological systems that are important in maintaining consciousness?
1) CVS
2) Respi
3) CNS
4) Electrolytes and energy
What is the role of the heart and blood vessels in maintaining consciousness?
Heart:
- HR and rhythm + SV
Vessels:
- Sufficient blood volume/BP
Together → adequate perfusion via cerebral circulation (carotid/vertebral/cerebral/venous system)
What is the role of the lungs and respiratory muscles in maintaining consciousness?
Lungs:
- air exchange → maintain pO2/pCO2 → adequate perfusion + prevent acidosis
Respiratory muscles:
- effective air exchange for lung function
What are 2 areas of the brain that help maintain consciousness?
1) Reticular activating system of brainstem
2) Cerebral hemispheric function (left more important for adequate function)
What are 4 energy substrates/electrolytes that are essential to maintaining consciousness?
1) Glucose
2) Ketones
3) K+
4) Ca2+
5) Na+
What is the difference between sleep and impaired consciousness?
A patient who is asleep can be awoken and regain full consciousness
What are the 4 levels of impaired consciousness?
Increasing severity:
1) Lethargy
- difficulty maintaining awake state
2) Obtunded/obtundation
- responsive to non-pain stimuli
3) Stupor
- only responsive to pain
4) Coma
- no clinical response to external stimuli
What is the GCS?
Measurement of consciousness level (3-15, <12 → BAD)
1) Eye-opening (E)
- spontaneous → voice → pain
2) Best verbal (V)
- orientated → confused → inappropriate → incomprehensible
3) Best motor (M)
- obey → localise → withdraw → pain flexion → pain extension
What are 4 limitations of GCS?
1) Cannot evaluate eye with severe orbito-facial injury
2) Cannot evaluate verbal if intubated
3) Cannot score differences between L/R function
4) Lack of neuro-ophthalmic evaluation (pupillary size/reactivity)
5) Lack of brainstem assessment
A lens-shaped bleed on a cranial CT is indicative of _______________________.
Epidural hematoma (arterial bleed from middle meningeal)
A crescent-shaped bleed on a cranial CT is indicative of __________________.
Subdural hematoma (venous bleed from bridging veins)
What are 12 causes of impaired consciousness?
1) Brain trauma
2) Cerebrovascular event
- hemorrhage, thromboemboli, vasculitis
3) Seizures/status epilepticus
4) Syncope
- transient cerebral hypoperfusion
5) CNS infection
- meningitis, encephalitis, brain abscess
6) Post-infectious/inflammatory rxn/disorder
- ADEM, MS
7) Medications
- OD of meds/multiple sedative meds
8) Drugs of abuse/alcohol
9) Toxins
10) Severe sepsis
11) Major organ failure
12) Electrolyte abnormalities, ABDs
13) Metabolic crisis
What are 4 causes of a comatose state?
Large and persistent area of brain affected:
1) Trauma
2) Cerebrovascular events
3) Encephalitis
4) Refractory status epilepticus
What is the most common cause of transient LOC?
Syncope
What is syncope?
Paroxysmal event with LOS and postural tone due to cerebral hypoperfusion (perfusion/oxygenation) with spontaneous recovery
How does falling over correct syncope?
Fall down → brain same height as heart → restored perfusion
What are 5 typical presentations of syncope?
1) LOC and postural tone
2) Pallor + sweating
3) Brief (~secs) extensor stiffening/spasm
4) Few irregular myoclonic jerks (convulsive syncope)
5) <30s per episode
What are 2 triggers for syncope?
Peripheral vasodilation
1) prolonged standing
2) Hot, closed, crowded areas with poor ventilation
↑Vagal tone
3) Painful stimuli
4) Fear/shock
How can syncope be averted when prodromal symptoms are experienced?
Lie down horizontally with head down and legs up
What are 4 prodromal symptoms of syncope?
1) Lightheadedness/ dizziness/ nausea
2) Warmth
3) Sweating
4) Vision greying/blackening
5) Hearing muffled/distant
What are 7 types of syncope?
Neurally-mediated:
1) Vasovagal
2) Reflex anoxic (pallid spells)
3) Orthostatic (no pallor and sweating)
4) Reflex-mediated situational syncope (Valsalva maneuver, micturition)
Cardiogenic:
5) Arrhythmias
6) Cardiac defects
7) Cardiomyopathies
What are seizures?
Sudden unusual/erratic electrical changes in cortical neurons → brief alteration in a person’s consciousness, sensation, movements, actions
