Vascular Neurology 2: Ischemic Stroke Flashcards
Percentage of strokes that are ischemic? Hemorrhagic?
Ischemic: 80%
Hemorrhagic: 20%
Old vs. new definition of TIA?
Old: Neurological symptoms resolve within 24 hours.
New: Neurological symptoms that resolve AND no evidence of permanent damage on scan.
What small arteries run from the MCA to the basal ganglia, internal capsule, thalamus, etc.? What is an infarct of these vessels called?
Lenticulostriate arteries. Infarct = lacunar stroke
Name 5 classic lacunar syndromes.
Pure motor hemiparesis Sensori-motor stroke Pure sensory stroke (note similarity of first 3) Dysarthria-clumsy hand syndrome Ataxic hemiparesis
What must be absent in order to diagnose a lacunar stroke? (2 things)
Cortical signs
Visual field involvement
When do you look for less common causes of stroke?
Young patients without common risk factors.
What is arterial dissection? How can it cause stroke?
Tear in blood vessel intima.
Exposed tissue is highly pro-thrombotic -> thromboembolus cause stroke.
Most significant modifiable risk factor for stroke?
Hypertension
What does a prior history of heart problems such as atrial fibrilation suggest about the possible cause of a patient’s stroke?
May be cardioembolic.
List stroke mimics. There are 9… (probably not the highest yield thing to spend your time on)
Seizure, migraine, hypo/hyperglycemia, other metabolic derangements, drug OD, head/neck trauma, intracranial mass, meningitis/encephalitis, and psychogenic.
Can you see an early ischemic stroke on a CT scan?
Yes, sometimes. (though not always) It’s more subtle than how a hemorrhagic stroke appears, but you can sometimes see a loss of grey/white matter differentiation.
What’s the most sensitive imaging modality for detecting an ischemic stroke? What does it show you?
Diffusion weighted MRI. Shows abnormal water movement in dying cells.
4 parts of acute care for (ischemic) stroke?
Reperfusion (thrombolysis)
Neuroprotection
Prevent recurrence (antithrombotic drugs)
Supportive care
2 variables determining how much damage is done during ischemic stroke?
Degree of blood flow reduction.
Time that it stays low.
What is the core/penumbra concept of ischemic stroke?
Core is the area hit first. You can’t do much about it. Penumbra is the surrounding range of affected cells that can be saved if the stroke is reversed.
What’s the drug of choice for ischemic infarct?
t-PA (tissue plasminogen activator)
Major drawback of t-PA? How many people have this bad outcome? What usage guidelines are made for this reason?
High risk of intracerebral hemorrhage (ICH)
1 in 15 people (6%)
Must give t-PA within 4 hours of symptoms (i.e. when benefit outweighs risk)
Don’t give to people with risk factors for ICH.
What is an alternative to t-PA for busting clots in ischemic stroke? Time window for use?
Mechanical thrombolysis (the spiral, roto-rooter things).
8 hours.
Could theoretically be used for people with ICH risk factors, but “their role is controversial.”
Is heparin used to prevent the recurrence of ischemic stroke?
Nope. Causes too many bleeds to produce a net benefit.
Choice of antithrombotic drug for ischemic stroke prevention varies with the cause of the stroke. What drugs are used for which types? Why the difference?
Cardioembolic: Anticoagulant drugs (e.g. warfarin)
Everything else: Antiplatelet drugs (e.g. aspirin, Plavix)
Anti-platelet drugs are safer and easier to use.
With recurrent TIAs, what does the localization tell you about the underlying cause?
Same location: Probably large vessel disease (e.g. carotid stenosis)
Different locations: Probably cardioembolic.
What score is used to estimate the risk for stroke after TIA? Variables in the score?
ABCD^2 Age Blood pressure Clinical features (unilateral weakness, aphasia) Duration Diabetes
Do venous thrombosis symptoms respect vascular territories?
Nope.
5 signs/symptoms of venous thrombosis.
Sudden focal deficits, seizures, headache, encephalopathy (a uselessly vague term?), and papilledema.
Why does venous thrombosis cause both infarct and hemorrhage?
Increased venous pressure prevents perfusion, arterial blood hemorrhages because it has nowhere else to go…
Treatment of cerebral venous thrombosis?
Anticoagulation with heparin. (contrast with treatment for arterial ischemic infarct)
Prof. notes local infusion of thrombolytic agents and mechanical thrombolysis as up-and-coming therapies.
time = ?
brain
