Neurology, Infarcts
Terms
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- define a stroke
- sudden, nonconvulsive focal neruologic deficit
- define a TIA (transient ischemic attack)
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1. deficit lasting <24 hr (usually <1 hr)
2. but resolves completely - where is the m/c emboli source for a stroke?
- 1. carotid atheroma
- what are common emboli sources for an infarct?
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1. carotid atheroma (m/c)
2. cardiac and fat emboli
3. marantic endocarditis (metastasizing cancer cells) - what is a Lacunar infarct?
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1. small infarct
2. deep in white mater
3. strongly a/c hypertension and atherosclerosis - where do watershed infarcts occur?
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at the border of areas supplied by different arteries
1. middle cerebral artery
2. anterior cerebral artery
3. often following prolonged hypotension - what is Wernicke's aphasia?
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1. Wernicke's is wordy
2. temporal lobe lesion
3. receptive aphasia
4. pt speaks fluently but words do not make sense - what aphasia comes from a temporal lobe lesion?
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Wernicke's
1. Wernicke's is wordy
2. receptive aphaisa
3. pt speaks fluently but words do not make sense - what is Broca's aphasia?
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1. Broca's is broken
2. frontal lobe lesion
3. expressive aphasia
4. pt is unable to verbalize - what are clinical changes 2-4 days postinfarct?
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1. edema occurs 2-4 days post infarct
2. decreased consciousness
3. projectile vomiting
4. pupillary changes - what is decorticate posturing?
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1. flexion of arms
2. decorticate=cortical lesion - what is decerebrate posturing?
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1. arm extension
2. decerebrate=midbrain or lower lesion - what is the ddx of an infarct?
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1. stroke
2. seizure
3. neoplasm
4. encephalitis
5. multiple sclerosis - what are m/c storke causes?
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1. local atheroembolic (35%)
2. cardiac (30%)
3. lacunar (15%)
4. parenchymal hemorrhage (10%)
5. subarachnoid hemorrhage (10%)
6. vasculitis, temporal arteritis, etc. (1%) - when is a CT indicated in an infarct?
- 1. in an acute infarct
- when is an MRI indicated in an infarct?
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1. subacute infarct
2. hemorrhage - what si/sz should you r/o when you suspect an infarct?
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1. EKG changes
2. loss of bowe/bladder control
3. tongue injury - why should you perform a lumbar puncture when you suspect a stroke?
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1. to r/o encephalitis
2. to r/i intracranial bleed - what is first-line tx for occlusive infarct?
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tPA within 3-6 hr of onset!!! (preferably 1 hr)
for occlusive dz only (do NOT use with an intracranial bleed!!!) - what is an absolute contraindication to tPA?
- Intracranial bleed!!!
- what underlying disorders should you try to correct in the event of an infarct?
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1. hyperlipidemia
2. hypertension
3. diabetes
4. valve abnormality
5. coagulopathy
6. atrial fibrillation - what is first line tx for an emoblic stroke?
- 1. give aspirin/warfarin anticoagulation for prophylaxis
- what are indications for an enarterectomy?
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1. if carotid is 70% occluded
2. pt having sx - what is an MRA?
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Magnetic resonance angiography
*used to see the arteries (e.g. at the base of the brain)
*shown well by MRA s/ use of any contrast - what is the prognosis of an infarct?
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1. 20-40% mortality at 30 days (20% atheroemboli, 40% bleed)
2. <1/3 pts achieve full recovery of lifestyle
3. atheroembolic strokes recur at 10% per yr - the presentation of amaurosis fugax (monocular blindness) suggests what artery and lobe for an infarct?
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1. carotid (emboli)
2. ophthalmic artery - the presentation of drop attack/vertigo/CN palsy/coma suggests what artery and lobe for an infarct?
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1. vertebrobasilar (emboli)
2. brainstem - the presentation of aphasia suggests what artery and lobe for an infarct?
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1. middle cerebral
2. dominant frontal or temporal (L=dominant in 99% of R-handers and >50% of L-handers) - the presentation of sensory neglect and apraxia suggests what artery and lobe for an infarct?
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1. middle cerebral
2. non-dominant frontal or temporal (R)
apraxia=pt cannot follow commands even if it is understood and the pt is physically capable of it - the presentation of Hemiplegia suggests what artery and lobe for an infarct?
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1. middle or anterior cerebral
2. contralateral parietal - the presentation of homonymous hemianopia suggests what artery and lobe for an infarct?
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1. middle or posterior cerebral A.
2. temporal or occipital lobe - the presentation of urinary incontinence and grasp reflex suggests what artery and lobe for an infarct?
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1. middle or anterior cerebral A.
2. Frontal lobe