A 5 Mechanisms of Stroke Flashcards
What is the distribution (percentage-wise) of each type of stroke?
- Ischemic: Arterial 81% (of these, 25% each belong to: Atherosclerotic, Cardioembolic, Lacunar, Other) and Venous 2%
- Hemorrhagic: Intracerebral 13% Subarachnoid 5%
-Ischemic strokes usually have focal, or general symptoms? Positive or negative?
- Focal
- Negative
T/F Perfusing the brain at a consistent (low) flow can allow some neurons to live for as long as an hour before then dying?
True (these would be in the penumbra, and would probably have reversible paralysis or other similar symptoms)
T/F Perfusing the brain at a low flow can kill some neurons within minutes?
True
TIA has what 2 definitions?
- Symptoms last less than 24 hrs
- No brain injury on imaging
After a TIA, across a week, month, year, what are approximate risk of having a stroke?
- Highest in first week
- 15-30% within a month
- 40-50% within a year
Where do clots in the brain usually form?
-Bifurcations (turbulent flow)
What are 3 procedures used to treat a blocked artery in the brain?
- Endarterectomy
- Angioplasty & stent
- Thrombolytics
Which type of stroke are anticoagulants most effective against?
Cardioembolic
Which two arteries receive most cardioembolisms?
MCA, PCA
Would an embolus to the brain come from the right or left side of the heart?
Either. (“Paradoxical embolus” from the right)
On a brain scan, how would you distinguish between a cardioembolic stroke and an amyloid angiopathy hemorrhage ?
Cardioembolic=multiple vascular territories
Amyloid angiopathy hemorrhage=Multiple territories within one lobe
What leads to a lacunar stroke?
- Thickened arterial wall (hypertension, diabetes)
- Occlusion
What area of the brain is damaged by a lacunar stroke?
- Basal ganglia (Putamen, caudate), thalamus, pons, internal capsule
- Less than 15 mm white matter
“Other causes” of stroke are most common in what age group?
young
What happens after an arterial dissection? What would it look like on an angiogram?
1) Clot forms at the edge of an intimal flap and the artery may occlude, or there could be severe hemorrhage.
2) Like a narrowing and then little or no blood flow beyond that point
Superior sagittal sinus thrombosis affects the brain how?
- Lots intracranial pressure
- Bilateral infarct
-What dies each minute in an acute ischemic stroke?
- 1.9 million neurons
- 14 billioin synapses
- 7.5 miles myelinated fibers
- May not need exact stats but this was one of the “objectives” of his lecture
How long might it take to see an acute infarct on a CAT scan?
-4 days ish
What does the dense artery sign indicate?
thrombus
Is diffusion or perfusion MRI better at finding at-risk brain tissue?
perfusion
What are potential neuroprotectives?
magnesium
What symptoms of a hemorrhagic stroke are different than ischemic?
- Not always different clinically
- “worst headache of life”
- Stiff neck
- cardiac symptoms from catecholamines
- Lots intracranial pressure (esp locally, and also diffusely, causing herniation)
What are the 2 mechanisms of a hemorrhagic stroke?
- Arteriopathy of a small vessel (hypertension, amyloid angiopathy, aneurysm, etc)
- Hematological (anticoagulants, genetic, etc)
Control of blood pressure and management of edema are the best TREATMENT (not prevention) for which kind of stroke?
-Hemorrhagic (iron is a target to reduce edema)
What is the best, and worst kind of strokes to have?
- Venous
- Hemorrhagic
How long might it take to see a hemorrhagic stroke (subarachnoid) on CT?
- After 1 day 98% are identifiable
- After 7 days, only 50% are identifiable
- (Recall ischemic may take 4 days ish to become visible)
How long after a hemorrhagic stroke can xanthocrhomia detect it?
- Up to 3 weeks
- Requires lumbar puncture (test tube compare to water)
For SUBARACHNOID hemorrhagic strokes, what is the best treatment?
- Secure the aneurysm
- Then manage the other probs like in any hemorrhagic stroke (recall B.P. and edema)
Small vessel disease results in which 2 types of stroke?
Lacunar stroke
Hypertensive inter-cranial hemorrhage
Small vessel disease leads to what 2 kinds of stroke?
- Lacunar (endothelial dysfunction)
- Hemorrhagic (charcot-bouchard microaneurysm), esp. subarachnoid hemo
