Syncope Flashcards
What is syncope? How does it differ from pre-syncope?
Syncope is a temporary loss of consciousness usually related to insufficient blood flow to the brain.
Pre-syncope is the sensation of near fainting or prodrome without actually passing out.
Factors that effect cerebral blood flow?
MAP (how much pressure the heart/ vessels can exert to bring blood into the brain)
ICP (the pressure exerted on the vessels in the brain by the brain tissue, synovial fluids/ CSF and other brain structures
What does the brain use to regulate blood flow?
The brain can alter resistance of the cerebral blood vessels. This depends on the pH and the PaCO2
O2 - only once things are really bad!
Increased ICP - what emergency measures can you take?
Can use an osmotic like mannitol, and can hyperventilate to drop CO2 as much as possible (prevent cerebral vasodilation)
Can like theoretically drill a burr hole but…
What is the most common type of syncope?
Vasovagal.
What is reflex syncope and how is it triggered?
As a result of pressure on the baroRC of the carotid sinus - triggered by head rotation or tight collar.
What triggers vasovagal syncope?
Stress, fear, noxious stimuli or heat exposure
Usually preceded by nausea, lightheadedness - has a prodrome
What triggers situational syncope?
Post-micturition, exercise, postprandial, with GI stimulation.
Criteria for orthostatic hypotension?
Decrease in systolic BP >20mmHg or diastolic >10mmHg within 3 minutes of standing from supine.
Causes of autonomic failure?
Primary - Parkinson’s, MS, Wernicke’s encephalopathy
Secondary - DM, amyloidosis, uraemia, spinal cord injury and connective tissue diseases
Drugs causing syncope?
Alcohol, insulin, anti-hypertensives, anti-diabetics, anti-depressants, anti-Parkinson’s
Types of cardiac syncope?
Valvular - AS is the most common form
Structural - HOCM, Aortic dissection, acute MI
Arrhythmias - most common cause can be due to bradycardia, severe tachycardia
Factor that might help distinguish syncope from seizure?
Post-ictal period, prodrome characteristic of a seizure, previous seizure hx, loss of bowel and urinary control, and tongue biting could be signs more of a seizure than syncope
Both can have myoclonus.
Syncope may have more an abrupt onset, be during exercise, postural, look at medications and past medical hx, age.
Focal vs generalized seizures?
Focal only involve part of the body, the person’s awareness may not be impaired
Generalized onset involves the whole body, and awareness is impaired.
Tonic vs clonic
Tonic - muscle contractions, rigidity
Clonic - jerking movements rapid
Treatment for acute seizure?
Lorazepam, most resolve spontaneously in which case all that is needed is airway support, CBG for glucose, IV access
Treatment for status epilepticus?
If the seizure does not resolve within 5 minutes, it is status, give lorazepam, and phenytoin, if this does not help switch to barbiturates. Final solution is sedation and intubation.
Treatment for Orthostatic hypotension?
Discontinue aggravating medications, modify daily activities. Compression stocking and abdominal binders.
Fitness to drive?
One vasovagal episode - no restrictions
Seizure - needs to be maintained without one and compliant to medical care for 6 months
Carcinoid syndrome
Evaluate for serotonin (5-HIAA) in the urine, is a type of neuroendocrine tumour
