Lecture 43: Vascular Neurology 2, Ischemic Stroke Flashcards
What is stroke?
Sudden focal neurological deficit due to vascular cause
Dead brain due to focal lack of blood flow
Due to vascular cause
-ischemia = 80% (stroke)
Cell death is caused by LACK of blood to the area
-hemorrhage = 20%
Transient ischemic attack (TIA)
-sudden focal neurological deficit
-due to ischemia by definition
-less than 24 hours
-do not result in permanent injury
Mechanism : thrombus/embolus in artery
Fissure and rupture of plaque
What is the significance of TIA?
It tells you of an impending stroke!
Treat exactly the same as stroke (except thrombolysis)
Don’t miss your chance to prevent a stroke by missing a TIA!!
High ABCD^2 score tells you that you need to treat the patient
What is the hallmark of stroke?
- Sudden onset
2. Focal brain dysfunction
What is hallmark of hemorrhage?
NOT sudden onset…progressive…
Difference between hypoxia and ischemia
Hypoxia: lack of oxygen
Example: severe asthma
Ischemia: lack of blood flow
Example: stroke
What are the 7 P’s of ischemic stroke?
Pump (cardioembolism…pump means heart)
Pipes (large artery disease)
Platelets (clotting risk factor)
Pressure (high blood pressure risk factor)
Perfusion (treatment option)
Penumbra (the part you want to save)
Prevention (prevent stroke because infarction is not treatable after it hits)
Ischemia can either be due to
A. Arterial -cardioembolism (20%) -large vessel atherothromboembolism (20%) -lacunar (25%) -cryptogenic (30%) -unusual cause B. Venous sinus thrombosis
What is cardioembolic stroke most commonly associated with?
- ATRIAL FIBRILLATION
- valve disease
- left ventricle myopathy (myocardial infarction)
What causes large vessel atherothromboembolism (Pipes)?
Carotid artery Stenosis
-stenosis of ICA can result in either a thrombotic or embolic stroke
-treatment is excision of the plaque by endarterectomy
Stenosis of vertebrobasilar system (not amenable to surgery)
Occurs at arterial bifurcation and tortuous points
What is a stent?
Put a balloon in a narrowed blood vessel and blow it up (to make artery less stenotic)
Treatment for stenotic arteries
What are the Watershed or borderzone areas? Why are they watershed areas?
1. Cortical border zone Between ACA and MCA 2. Internal border zone Between LCA and MCA 3. Cortical border zone Between MCA and PCA
What is man in a barrel syndrome?
The classic syndrome of bilateral watersheds
ACA-MCA boundary suffers from ischemia
Symptoms:
-weakness of both arms
-called man in the barrel because its like the dude has a barrel around his trunk (cant use arms but head and legs are fine)
MOA of small vessel (lacunar) stroke? Symptoms?
MOA: hypertension, diabetes
Only a lacunar stroke if it is a perforating artery (internal capsule, thalamus)
Symptoms:
Pure motor hemiparesis (internal capsule)
-sensori-motor stroke (thalamus and internal capsule)
-pure sensory stroke (PCA in thalamus)
-dysarthria-clumsy hand syndrome (pons is fucked)
-ataxic hemiparesis (pontine lesion)
AND
lack of cortical symptoms, visual involvement
What is cryptogenic stroke?
What you call a stroke when there is no identifiable stroke mechanism lmao
-half of strokes in young patients are cryptogenic
Treatment = antiplatelet therapy
What are other notable mechanisms for ischemic stroke? Significance?
Significance: disproportionately high number of young people have “other mechanism” and don’t fall into the categories above Notable causes -cocaine -Syphilis -carotid dissection -vasculitis -prothrombotic disorders
What is arterial dissection?
Injury to vessel wall
Tear in intima exposes thrombogenic surface
Looks like a flap that was torn off of vessel wall
Commonly occurs in neck due to torsion
What does carotid bruit tell you?
Possible stenosis
What does blood look like on CT?
It looks white
Darkness = infarction, ischemic stroke
What is diffusion-weighted imaging (DWI)?
A type of MRI
The most sensitive tool you have to detect infarction…for distinguish TIA patients if they have injury or not
Measures how water moves in cells…if cell can’t transport water, then image appears white
Therefore, bright white = area of infarction
-If you see nothing in the DWI, then you know it is a TIA
What are your treatment options once you determine it is an ISCHEMIC rather than HEMORRHAGIC stroke?
- Reperfusion
- restore cerebral blood flow
- t-PA!!!
- Neuroprotection
- minimize the damage
- Antithrombotic therapy
- prevent recurrent thromboembolism
- Supportive Care
What is penumbra region?
The area directly surrounding the infarcted area (penumbra is the target of our therapy)
-basically the brain tissue that should still be viable
Save the penumbra!
What type of antithrombtic medicine is used as part of thrombolysis treatment?
t-PA (activates plasminogen into plasmin)
Complete resolution with tPA
However, there is a side effect of hemorrhage
How do you prevent recurrent thromboembolism?
Aspirin (not heparin anymore)
What is the significance of supportive care for stroke?
Importance of supportive care cannot be understated
For every degree that a stroke patient’s body temp is elevated, the likelihood of being severely disabled or dead will double
Therefore, keep the patient hypothermic!!
-raise the blood pressure so that more blood can get there
-normal saline can also improve cerebral blood flow
What are the three major medical causes of death in stroke patients?
- Infections
- DVT and Pulmonary embolus
- myocardial infarction
All of which are preventable with supportive care
What is the ABCD^2 score?
Used to identify stroke risk with patients with TIA
Age
Blood pressure
Clinical Feature
Duration of symptoms
Diabetes
If you have an ABCD^2 score of 6 and higher, 8% chance to get stroke in next 2 days so this is the group of TIA patients you want to target
How does cerebral venous sinus thrombosis present?
It does NOT respect vascular territories
- sudden focal deficits - seizures - headache - encephalopathy - papilledema
What is treatment for CVT (cerebral venous thrombosis)
Anti-coagulation with heparin
-local infusion of thrombolytic agents
Mechanical clot disruption
What is the significance of seizure?
It localizes to cortical dysfunction
