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12 Cards in this Set
- Front
- Back
What is ischemic stroke?
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Sudden neurological dysfunction due to vascular cause
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What is the epidemiology of ischemic stroke?
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Ischemic stroke accounts for 90% of all strokes
Fourth leading cause of death in US |
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What is the mortality rate of ischemic stroke?
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20-30% mortality rate at 3 months when there is vessel occlusion
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What are the causes of ischemic stroke and what are the relative frequencies of each?
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Each accounts for 25% of all cases:
1) Cardioembolic stroke = source of clot came from heart - Includes: atrial fibrillation (especially in elderly, atria are prone to irregular heartbeat), Valvular Heart Disease 2) Small vessel disease = occlusion of vessels 0.05 - 0.5mm in diameter (arterioles) - Often due to: hypertension, diabetes 3) Large vessel disease = occlusion of vessels 1-4mm in diameter eg. carotid artery, middle cerebral artery (MCA) - Often due to: high cholesterol 4) Unknown cause - e.g. Stroke due to arterial dissection (tear - leads to clot), blood coagulation abnormality |
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What is the basic distribution of blood vessels in the brain?
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Rostral brain:
- Internal carotid → bifurcates: ACA (medial) & MCA (lateral) MCA → bifurcates: M2 segments (superior and inferior branches - designated for therapeutic purposes) Caudal brain: - 2 Vertebral arteries (1 is usually larger than the other) - Vertebral join together → basilar -- Branch off of vertebral → PICA -- Branch off of basilar → AICA, SCA, PCA |
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What are the symptoms of an MCA stroke?
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- Contralateral:
-- hemiparesis (weakness) - Face, Arm > Leg -- hemianesthesia (sensory loss) -- homonymous hemianopia - Eyes deviate to side of lesion - Left MCA stroke = Aphasia (difficulty communicating or understanding speech) - Right MCA stroke = Left visual field Neglect (i.e: Asomatognosia - do not recognize own limbs) -- 1/3 to 1/2 patients do recover from neglect |
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What are the symptoms of a lacunar stroke?
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- Hemiparesis w/ out aphasia or neglect
- Brainstem Lacunes → crossed findings - Examples: -- Midbrain lesions: --- Weber = CN3 Palsy + contralateral hemiplegia --- Benedikt = CN3 Palsy + contralateral dysmetria -- Pons lesion: --- Millard- Gubler = stroke in pons = CN6 + CN7 Palsy + contralateral hemiparesis = crossed signs, ipsilateral face weakness, contralateral body weakness -- MLF lesion (midline of the brain stem) --- Internuclear Ophthalmoplegia (occurs ipsilateral to MLF lesion) = upon lateral gaze, the eye ipsilateral to the MLF lesion is unable to adduct and the opposite eye shows nystagmus = skewing of eyes. Convergence is still possible (because it is NOT a CN 3 palsy). [this was the a small group case] * Lacunar Artery = single deep penetrating artery that arises directly from the constituents of the Circle of Willis, cerebellar arteries, and basilar artery |
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What are the symptoms of a spinal cord infarction?
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Affects anterior portion of spinal cord
Occurs typically in setting of AAA (abdominal aortic aneursym) rupture or repair with hypoperfusion Can be associated renal failure Impaired motor (i.e: paralysis of legs) and pain/temp loss Preserved position/vibration sense (which are found in dorsal column) |
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What is NNT?
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Number Needed to Treat
Represents the number of people that need to be treated (with a drug, typically) for there to be a guaranteed effect in one individual. So, NNT 1 means every person that is treated is guaranteed to have an effect, while NNT 100 means that out of 100 patients treated, only 1 is guaranteed to have an effect |
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What are proven treatments of acute stroke?
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- tPA - potent blood thinner/clot remover that clears obstructed vessels
-- The sooner it's used, the better - 90m -> NNT 3, 180m -> NNT 8, 270m -> NNT 23 -- Screening: --- < 4.5 hours of stroke (need to know "time last known well") --- No hemorrhage on CT --- BP < 185/110 --- Glucose 50-400 --- Platelets > 100 --- INR < 1.7 (not on warfarin or other blood thinners) --- No recent procedures - Aspirin -- NNT 100 -- Used for tPA non-eligibles -- Needs be < 48 hours of stroke - Stroke Units (area in hospital dedicated to stroke patient care) -- NNT 20-30 |
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What are unproven treatments of acute stroke?
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Heparin and Heparinoids (not even in atrial fibrillation or large vessel atherosclerosis such as carotid stenosis)
Oxygen Intravenous fluids = raises blood pressure and improves perfusion to brain Laying head of bed flat = improve perfusion to brain Modify BP = BP too high or too low is bad Intra-arterial therapy = catheter to loosen clot in vessel (controversial) - Recent trials show that this is not a beneficial treatment, maybe unless it’s done at hour 1 (not hour 5 or 6) |
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What are the main components of stroke prevention?
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ABCDE
A: Antiplatelets - non-atrial fibrillation stroke, Anticoagulants - atrial fibrillation stroke - Antiplatelets include aspirin and clopidogrel -> should not be combined > 12 months due to increased bleeding risk with no benefit - Anticoagulants include warfarin, apixaban, rivaroxaban, dibagatran, all reducing intracranial hemorrhage risk, but increasing GI bleeding risk B: Blood pressure control - No ideal target, generally 140/90, lacunar <130/80 - With pharmacological (ACE inhibitors, ARB diuretics, Ca2+ channel blockers, B-blockers, A-blockers), non-pharmacology ( ↓ salt diet, DASH diet) C: Carotid artery repair - surgery (carotid endarterectomy) or stent, cholesterol lowering, smoking cessation - carotid artery narrowing happens and it is bad, bad cholesterol is bad, smoking is bad D: Diet - Low fat, high fruit/veggie E: Exercise 30 mins/day, encourage exercise in post-stroke patients due to tendency to reduce physical activity |