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Stroke
N/A
45
Anatomy
Graduate
02/15/2012

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Cards

Term
The term stroke, or cerebrovascular accident, refers to what?
Definition
A sudden focal neurological syndrom resulting from cerebrovascular disease
Term
How is stroke generally characterized?
Definition
Sudden onset with subsequent recovery of brain function occurring gradually and to a varying degree
Term
What are general pathological processes that affect cerebral vasculature and may lead to a stroke?
Definition
Occlusion of the vessel lumen, vessel rupture, altered vessel wall permeability, changes in the viscosity or quality of blood that affect blood flow
Term
What are nonmodifiable risk factors for stroke?
Definition
Age, ethnicity, gender, family history, genetics
Term
What are modifiable risk factors for stroke?
Definition
Arterial hypertension, transient ischemic attacks, prior stroke, asymptomatic carotid bruit/stenosis, cardiac disease, aortic arch atheromatosis, diabetes mellitus, dysplipidemia, smoking, alcohol, oral contraceptives, obesity
Term
How long does it take for interruption of cerebral blood flow to suppress/reduce brain electrical activity?
Definition
12-15s
Term
How long does it take for interruption of cerebral blood flow to inhibit synaptic excitability of cortical neurons?
Definition
2-4 minutes
Term
How long does it take for interruption of cerebral blood flow to inhibit electrical excitability altogether?
Definition
4-6 minutes
Term
The point following the inhibition of electrical excitability due to cerebral ischemia is known as what?
Definition
Threshold of membrane failure
Term
What is the pattern of ischemia caused by a stroke? Why does it exhibit a pattern?
Definition
A core of lost tissue surrounded by a penumbra of ischemic tissue, due to strokes producing reduced cerebral blood flow to some areas and complete loss to others
Term
The area of reduced blood flow in a stroke is known as what?
Definition
Ischemic penumbra or area of misery perfusion. Lies somewhere between thresholds of cell dysfunction and cell death
Term
An occlusive stroke is defined as what?
Definition
Most common form of stroke, is due to closure of a blood vessel following embolism, thrombosis, or small vessel disease
Term
A hemorrhagic stroke is defined as what?
Definition
Stroke due to bleeding from a vessel caused by hypertension, aneurysm, or atreriovenous malformation
Term
What defines a cerebral embolism?
Definition
Occlusion of a cerebral vessel by some exogenous material traveling within the vessel, most commonly a thrombus (blood clot)
Term
What is most commonly occluded in the anterior circulation?
Definition
Superficial branches of the middle cerebral artery
Term
What is most commonly occluded in the posterior (vertebrobasilar) circulation?
Definition
Cerebellar or posterior cerebellar artery
Term
What is the progression of damage due to an embolus?
Definition
Ischemia (localized anemia) -> infarcation (vascular insufficiency causing necrosis)
Term
Atherosclerosis affects what arteries?
Definition
Major extracranial and intracranial arteries, as well as the aorta prior to the major vessels
Term
Where do thrombi that form emboli appear in the heart?
Definition
Left atrium, mitral valve, or aortic valve
Term
What are the intracranial hemorrhages usually associated with stroke?
Definition
Suparachnoid, intraventricular, or parenchymatous cerebral hemorrhages
Term
What is the most common form of direct hemorrhage associated with stroke?
Definition
Sub-arachnoid hemorrhge
Term
Why are cerebral hemorrhages characterized as lacunar?
Definition
They multiply in incidence over time
Term
What are major risk factors for cerebral hemorrhage?
Definition
Hypertension, diabetes, and atherosclerotic disease
Term
What defines an aneurysm?
Definition
Dilation of a vessel wall with the cavity remaining continuous with the vessel of origin
Term
Intracranial aneurysms most frequently occur at what points?
Definition
Branch points of vessels
Term
What are some treatments for aneurysms?
Definition
Clipping the aneurysm at the stalk or running a wire coil into the aneurism to induce clotting
Term
What usually causes a congenital aneurysm?
Definition
Weakness of the tunica media near a branch of the circle of Willis
Term
What are some symptoms of aneurysm rupture in the subarachnoid space?
Definition
Severe headache, mental confusion, loss of consciousness
Term
Carotid aneurysms in the cavernous sinus can result in the compression of what cranial nerves?
Definition
III, IV, VI, maxillary branches of V, and opthalmic
Term
Arteriovenous malformations are defined as what?
Definition
Abnormal communication between cerebral arteries and veins resulting in a tortuous mass of interconnecting channels
Term
What arteriovenous malformation is considered a special type seen primarily in newborns or infants?
Definition
Malformations of the great cerebral vein of Galen
Term
Arteriovenous malformations of the great cerebral vein of Galen induce what symptoms?
Definition
Bulging fontanelles, progressive hydrocephalus, dilated veins of the face and scalp
Term
Occlusion of what vessel may cause an infarction of the entire hemisphere with the exception of the thalamus, inferior portion of the temporal lob, and medial portion of the occipital lobe?
Definition
Internal carotid
Term
What defines a transient ischemic attack?
Definition
A small emboli partially occluding a small cerebral vessel, producing sudden neurological deficits that last less than 24 hours, typically less than 10 minutes
Term
How is recovery from a transient ischemic attack characterized?
Definition
Recovery is complete
Term
A transient ischemic attack in the retinal branches of the opthalmic artery produces what?
Definition
Amaurosis fugax - transient blindness on the affected side seen often as a window shade over the eye
Term
How do transient ischemic attacks act as prognostic indicators of stroke?
Definition
1/3 of untreated transient ischemic attack patients suffer from a stroke within 5 years
Term
What are symptoms of transient ischemic attacks in carotid circulation?
Definition
Ipsilateral amaurosis fugax, contralateral sensory or motor dysfunction, language deficits
Term
What are symptoms of transient ischemic attacks in vertebrobasilar circulation?
Definition
Bilateral or shifting motor sensory dysfunction, bilateral visual disturbances, bifacial numbness, vertigo, diplopia, ataxia
Term
Where are the watershed zones?
Definition
Border zones between the area supplied by the anterior, middle, and posterior cerebral arteries
Term
What might cause ischemia in watershed zones?
Definition
Cardiac surgery, severe arterial hypotension, prolonged hypoxemia, and severe carotid artery disease
Term
Where do lacunar infarction occur?
Definition
Ischemic strokes in the deep region of the brain or brainstem (excluding the cerebral cortex)
Term
Lacunar infarctions result form the occlusion of what arteries?
Definition
Anterior choroidal, middle cerebral, posterior cerebral, and basilar arteries, results in little cavities filled with fluid
Term
What are risk factors for lacuna infarctions?
Definition
Chronic hypertension and diabetes mellitus
Term
What are common syndromes of lacunar infarctions?
Definition
Pure motor stroke involving descending motor fibers, ataxic hemiparesis (clumsy hands), pure sensory stroke
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