Stroke Flashcards
Stroke is the ___ leading cause of death in the US
3rd
What are the 2 kinds of strokes?
- Infarcts (thrombotic or embolic)
- Hemorrhages
What are the 3 subtypes of ischemic stroke?
- lacunar infarct
- carotid circulation obstruction
- vertebrobasilar occlusion
What are the 4 subtypes of hemorrhagic stroke?
- spontaneous intracerebral hemorrhage
- subarachnoid hemorrhage
- intracranial aneurysm
- arteriovenous malformations
Describe lacunar infarcts
They are small lesions (<5 mm in diameter) that occur in the distribution of short penetrating arterioles in the basal ganglia, pons, cerebellum, internal capsule, thalamus
What are lacunar infarcts associated with?
poorly controlled hypertension or diabetes
The prognosis for recovery from the deficit produced by a lacunar infarct is usually good, with partial or complete resolution occurring over the following - weeks in many instances.
4-6
What leads to a cerebral infarction?
A thrombotic or embolic occlusion of a major vessel
What causes a cerebral infarction?
- TIA causes
- atherosclerosis of cerebral arteries
What does deficit following a cerebral infarction depend on?
the particular vessel involved and the extent of any collateral circulation
What leads to an increase in neurologic deficit following a cerebral infarction?
Cerebral ischemia leads to the release of neuropeptides that augment calcium flux into neurons, thereby leading to cell death and increasing the neurologic deficit.
Onset of stroke is usually _____.
abrupt
What does occlusion of the ophthalmic artery lead to?
Amaurosis fugax (sudden and brief loss of vision in one eye)
What does an occlusion of anterior cerebral artery distal to its junction with anterior communicating artery lead to?
- weakness and cortical sensory loss in the contralateral leg
- mild weakness of the arm (especially proximally)
- contralateral grasp reflex
- paratonic rigidity
- abulia (lack of initiative)
- frank confusion
- urinary incontinence
- marked behavioral changes
- memory disturbances
What does an occlusion of middle cerebral artery lead to?
- contralateral hemiplegia
- hemisensory loss
- homonymous hemianopia
- global aphasia
- drowsiness
- stupor
- coma in extreme cases
Involvement of the anterior main division of the middle cerebral artery leads to what?
- expressive dysphasia
- contralateral paralysis and loss of sensations in the arm, the face and, to a lesser extent, the leg
Involvement of the posterior main division of the middle cerebral artery leads to what?
- receptive (Wernicke) aphasia
- homonymous visual field defect
Occlusion of posterior cerebral artery leads to what syndrome?
thalamic syndrome
What are the signs of thalamic syndrome?
contralateral hemisensory disturbance, followed by the development of spontaneous pain and hyperpathia
How is vision impaired following occlusion of the posterior cerebral artery?
macular-sparing homonymous hemianopia
What happens when the small paramedian arteries arising from vertebral artery are occluded?
- contralateral hemiplegia and sensory deficit
- ipsilateral cranial nerve palsy at the level of the lesion
What happens when the posterior inferior cerebellar artery is occluded?
- ipsilateral spinothalamic sensory loss involving the face
- ninth and tenth cranial nerve lesions
- limb ataxia and numbness
- Horner syndrome
What happens when the major cerebellar arteries are occluded?
- vertigo
- nausea
- vomiting
- nystagmus
- ipsilateral limb ataxia
- contralateral spinothalamic sensory loss in the limbs
What may a massive cerebellar infarction lead to?
coma, tonsillar herniation, and death
Infarction in what 2 areas my lead to LOC?
- carotid territory
- vertebrobasilar territory
Coma occurs when there is a bilateral brainstem infarction that involves which structure?
the reticular formation
What is the preferred first imaging technique?
CT without contrast
CT should occur before what?
The administration of aspirin or other antithrombotic agents
What is effective in reducing the neurologic deficit in selected patients without CT evidence of intracranial hemorrhage?
Intravenous thrombolytic therapy with recombinant tissue plasminogen activator (rtPA)
What is the time window in which patients can receive tPA?
1 - 4.5 hours
What are the contraindications to intravenous thrombolytic therapy?
- recent hemorrhage
- increased risk of hemorrhage (treatment with anticoagulants)
- arterial puncture at a noncompressible site
- systolic pressure > 185 mm Hg or diastolic pressure > 110 mm Hg
What non-thrombolytic treatment is used to treat thrombotic stroke?
endovascular intra-arterial tPA or mechanical removal of an embolus/clot
How is elevated intracranial pressure treated?
- Head elevation
- Mannitol
- Decompressive hemicraniectomy
Should BP be attempted to be lower in hypertensive patients following stroke?
No
What is the immediate treatment recommendation for patients contraindicated for thrombolytic treatment?
aspirin daily
The prognosis for survival after cerebral infarction is ____ than after cerebral or subarachnoid hemorrhage
better
What does prognosis of acute stroke depend on?
the time that elapses before arrival at the hospital
What implies a poorer prognosis after a cerebral infarct?
Loss of consciousness
What reduces the risk for recurrent strokes of MIs?
statin therapy to lower serum lipid levels
Antiplatelet therapy reduces the recurrence rate by __% among patients without a cardiac cause for the stroke who are not candidates for carotid endarterectomy
30
