Ischemic & Hemmorrhagic Stroke- Dx & Management
Terms
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- What non-modifiable risk factors have been associated with stroke?
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Advancing age (independent factor)
Hypertension (#1 based on prevalance)
Hx of TIA
Atrial fibrillation associated with valvular dz increase risk the most, non-valvular afib less so - What is the most common cause of ischemic stroke?
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Cardiogenic embolism
small penetrating arterial dz (lacunar infarct), large artery dz and cryptogenic stroke - What is the yearly mortality associated with all strokes?
- 25%
- Discuss the 30-day mortality rate of thrombotic and embolic stroke.
- Embolic rate is higher then thrombotic due to the propensity to have further emboli in the brain.
- What is the major underlying pathology associated with extracrainal/larger arteries in the brain?
- deposition of lipid in the subendothelium (arterio/atherosclerosis) leading to ectasia and stenosis of arteries
- What is ectasia?
- vascular enlargement
- What is a lacune?
- small subcortical infarction associated with lipohyalinosis (lipid dep), disruption of arterial wall and fibrinoid necrosis of penetrating arteries. Most frequently occuring and most benign brain infarction.
- What is the appearance of ischemic infarcts on CT?
- Low density (hyodense)
- What are early signs of infarction frequently noted on CT?
- effacement of cortical sulci, or loss of cortical ribbon (area between frontal/temporal lobes) definition
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How do infarcts appear on MRI?
T1? T2? -
MRI infarcts appear as low signal or dark (hypointense)
on T1 weighted images. On T2 weighted images appear bright (high signal). On DWI very bright - What is ischemic penumbra?
- Salvageable hypoperfused areas of the brain circrumscribing the necrotic area....detected with perfusion weighted imaging
- What clincal syndromes are associated with occlusion of the middle cerebral artery?
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1. hemiparesis
2. hemisensory loss
3. language deficit (w/left hemisphere involvement)
4. spatial/visual neglect
(w. right hemishpere involvement) - What clincal syndromes are associated with occlusion of the anterior cerebral artery?
- weakness involving contralateral leg (least frequent)
- What clincal syndromes are associated with occlusion of the posterior cerebral artery?
- contralateral hemianopsia (visual field loss)
- What clincal syndromes are associated with occlusion of the verterbral-basilar arteries?
- vertigo, dysarthria, diplopia, ataxia, hemiparesis, hemisensory changes
- Discuss syndromes associated with lacunar infarct?
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1. pure motor hemiparesis
2. pure sensory loss
3. ataxic-hemiparesis
4. dysarthria-clumsy hand syndome
lacunar infarcts are due to occlusion of small subcortical penetrating arteries. - What symptoms are associated with multifocal and bilateral lacunes?
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1.multi-infarct dementia
2. gait disorders
3 dysarthria
* This triad is called the lacunar state - What is the treatment/ work-up for ischemic stroke?
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1. MRI, MRA, DWI, carotid dopplers
2. Echocardiogram (to rule out cardiac source) *look for PFO in young- a common cause of stroke from paradoxical embolus
3. Treatment of risk factors
4. *IV heparing anitcoagulation. - Define crescendo TIAs.
- multiple Transient ischemic attackes occuring in a short period of time.
- What is the benefit of IA rtPA versus IV tPA?
- Intraarterial extends the window in which tPA can be administered to 6 hours for anterior circulation and 12 hourst for posterior circ.(brainstem)
- What is the MERCI device?
- A clot retrieval device that can be used withing 8 hours of the onset of ischemic stroke.
- What patients should be considered for CEA (Carotid Endarterectomy)?
- Patients with non-disabling infarcts that have symptomatic (stroke or TIA) internal carotid artery stenosis of > 70%, non-symptomatic the cutoff is 60% occlusion
- Define "malignant" MCA Infarction? What is the treatment?
- Hemispheric MCA infarct with significant edema. Tx: Hemicraniectomy with duroplasty or dehydrating osmotic agents (mannitol)
- T/F CEA immediately following acute stroke is contraindicated?
- T. Surgical cannulation of a thrombosed ICA following a cerebral infarction could lead to hemorrhagic conversion of bland infarct with resultant mass effect.
- T/F carotid bruit is not neccessarily essential for Dx of carotid stenosis.
- Presence of carotid bruit may indicated stenosis, but absence can indicate patency or highly stenosed vessel permitting very little flow.
- How does one effictively prophylax against thrombotic stroke?
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Antiplatelet agents
1. aspirin
2. Clopidogril (Plavix)
3. Aggrenox (combo of dipyrimadole and aspirin) - From where do brain emboli arise?
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Cardiac sources (a-fib, mural thrombi, infective endocarditis)
Non-cardiac sources (artery-artery embolus from any atherosclerotic source)
Annuerysms...cardiac dissection - Where are most brain emboli localized?
- Middle cerebral artery (MCA) affecting primarily cortical areas
- Discuss the pathophysiology of hemmorrhagic conversion of ischemic stroke.
- Emboli may break up after a brain infarction permitting reperfusion and hemmorrahgic infarction (hemorrhage will be high density white on CT scan)
- What is the treatment for embolic infarction? What about embolic infarction secondary to carotid dissection.
- Anticoagulation with IV heparin followed by warfarin for Embolic Stroke. Carotid dissection pts are anticoagulated for 6mos and converted to an aspirin/day.
- What are the two causal pathologies associated with primary intracerebral hemorrhage?
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Hypertension and cerebral amyloid angiopathy (CAA).
*CAA is frequently associated with lobar hemorrhage. - What are the four most common sites affected by hypertensive Intracerebral hemorrhage?
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Thalamus
Basal ganglia (putamen)
pons
cerebellum - What three factors determine the outcome of intracerbral hemmorhage?
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1. Size of hemmorhage (>60cc has a 70-80% mortality)
2. Location (deeper lesions are worse)
3. Initial clinical presentation - How is ICH treated?
- maintainenance of blood systolic pressure between (150-160mHg)
- For what types of hemorrhages is surgical evacuation indicated?
- Lobar or superficial, Surgical evacuation will reduce the mass effect
- True/False. Surgical evacuation is indicated for deep hemorrhages in the left hemisphere?
- False. Surgical evacuation in the dominant hemisphere may lead to speech difficulties. It is seldomly efficacous in deep hemorrhages.
- Discuss the pathophysiology of subarachnoid hemorrhage (SAH)?
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Saccular annuerysm ("berry")...occuring most often in women ages 40-60.
Less commonly (AVM) arteriovenous malformations as they bleed intraparenchymally young patients (not into the Sub arachnoid space). Typically present as the "worst headache of my life" - What are the three most common sites for saccular annuerysms?
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1. Junction of ICA and 1.Posterio communicating arteries
2.ACoM a
3.MCA
4.PICA (posterior internal carotid) - What is xanthochromia?
- yellow-tinged appearanec of CSF due to breakdown of blood products...usually seen in SAH
- T/F. A normal CT scan rules out Subarachnoid hemmorrhage.
- False. LP should be performed as xanthochromia is typically present 6 hours after SAH.
- What are secondary complications of SAH?
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1. Rebleeding (clipping or coil embolization reduces risk)
2. Vasospasm or (DCI) delayed cerebral ischemia- due to irritation of vasculature by metabolic products of blood - What is the treatment for SAH?
- Nimodipine (oral Ca channel blocker)...prophylaxis for vasospasm.
- For what pathology is treatmemnt "triple-H" indicated?
- Vasopasm. 3H (hypertension, hemodilution and hypervolemia) instituted to restore or aid perfusion
- What vasculopathies are frequently associated with brain infarctions and TIA's?
- dysimmune vasculopathies such as SLE, thrombotic thrombocytopenic purpura and antiphospholipid antibody syndrome.
- What symptoms are frequently associated with TIA's?
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Aneterior
Transient aphasia, dysarthria, numbness/weakness on one side of the body, loss of vision in one or both eyes
Posterior
diploplia, vertigo - Define aphasia.
- language difficulty
- Define dysarthria.
- slurred speech
- Define amaurosis fugax & hemianopsia.
- loss of vision in one or both eyes respectively.
- True/False. Loss of consciousness are frequently associated with TIA's.
- False. Loss of consciousness is rare with TIA's
- True/False. Cardiac Emboli are rarely causal for TIA's.
- True.
- Why is TIA considered a medical emergency?
- 5% of patients have a stroke within 2days of TIA onset. 10% have strokes within 90days after onset.
- How is TIA treated?
- Dependent upon etiology...if carotid artery stenosis (70%) CEA is recomended. Otherwise anticoagulation with warfarin or antiplatelet therapy (aspirin, clopidogrel or aggrenox) reduce recurrence of TIA or stroke.
- True/False. Low dose of alcohol is neuroprotective against stroke.
- True.
- True/False. If you have a stroke your risk of dying will be from a subsequent stroke.
- True.