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