CVA help?!?!

a stroke, or cerebrovascular accident, is a sudden impairment of cerebral circulation in one or more blood vessels. a stroke interrupts or diminishes oxygen supply, and commonly causes serious damage or necrosis in the brain tissues. the sooner the circulation returns to normal after a stroke, the better the chances are for a complete recovery. however, about one-half of the patients who survive a stroke remain permanently disabled and experience a recurrence within weeks, months, or years. it's the leading cause of admission to long-term care. it is the third most common cause of death in the united states and the most common cause of neurologic disability. it strikes more than 500,000 people per year and is fatal in approximately 50% of them. most patients experiencing strokes are over age 65, although they may occur in younger people. incidence is higher in blacks than in whites. blacks have a 60% higher risk of stroke than whites or hispanics of the same age. this is believed to be the result of an increased prevalence of hypertension in blacks. in addition, strokes in blacks usually result from disease in the small cerebral vessels, whereas strokes in whites are typically the result of disease in the large carotid arteries. the mortality rate for blacks from stroke is twice the rate for whites.

strokes are classified as ischemic or hemorrhagic. there are three types of ischemia strokes: thrombotic, embolic and lacunar.

thrombosis of the cerebral arteries supplying the brain or of the intracranial vessels occluding blood flow is the most common cause of strokes in middle-aged and elderly people. it is commonly the result of atherosclerosis, but also associated with hypertension, smoking and diabetes. a thrombus in an extracranial or intracranial vessel blocks blood flow to the cerebral cortex. the carotid artery is the most commonly affected extracranial vessel. common intracranial sites include the bifurcation of the carotid arteries, distal intracranial portion of vertebral arteries, and proximal basilar arteries. thrombotic stokes commonly occur during sleep or shortly after awakening, during surgery, or after a myocardial infarction.

an embolism from outside the brain, such as in the heart, aorta, or common carotid artery can occur at any age, especially among patients with a history of rheumatic heart disease, endocarditis, posttraumatic valvular disease, myocardial fibrillation and other cardiac arrhythmias, or after open heart surgery. these embolisms float into the cerebral bloodstream and lodge in the middle cerebral artery or one of its branches. it is the second most common type of stroke. these types of strokes typically occur during activity and develop rapidly. these emboli commonly originate during atrial fibrillation.

this is a type of thrombotic stroke. hypertension creates cavities deep in the white matter of the brain which affects the internal capsule, basal ganglia, thalamus and pons. the lipid coat lining the small penetrating arteries thickens and weakens the walls of these blood vessels causing microaneurysms and dissections.

this is the third most common type of stroke. a rupture occurs in an intracranial artery or vein as a result of hypertension, aneurysm, arteriovenous malformations, trauma, hemorrhagic disorders or a septic embolism. hypertension and ruptured aneurysms are the most common causes. it can occur at any age. as a result there is diminished blood supplied to the tissues fed by the ruptured artery and compression of the brain cells by accumulated blood. when hemorrhage has occurred the blood that has spilled among the brain cells acts as a space-occupying mass that exerts pressure on the brain tissue. at first, ruptured cerebral blood vessels may constrict to limit blood loss which further restricts blood flow to the area of stroke and promotes ischemia. blood cells can also migrate into the spaces where cerebral spinal fluid circulates and cause blockages of this fluid circulation resulting in hydocephalus.

when any type of stroke occurs, there is deprivation of oxygen and nutrients to the affected area of the brain. when blood flow in a blood vessel remains blocked for more than a few minutes, oxygen deprivation leads to infarction of brain tissue. the brain cells cease to function because they can neither store glucose or glycogen for use nor engage in anaerobic metabolism.

a tia (transient ischemic attack) is an episode of neurologic deficit resulting from cerebral ischemia. the recurrent attacks may last from seconds to an hour. it's usually considered a warning sign for stroke. in 14% of patients who experience a tia, another tia or a full stroke will occur within one year.

in a tia, microemboli released from a thrombus may temporarily interrupt blood flow, especially in the small distal branches of the brain's arterial tree. small spasms in those arterioles may impair blood flow and also precede a tia.

the most distinctive features of tias are transient focal deficits with complete return of function. the deficits usually involve some degree of motor or sensory dysfunction. they may range to loss of consciousness and loss of motor or sensory function, but only for a brief time. commonly, the patient experiences weakness in the lower part of the face and arms, hands, fingers, and legs on the side opposite the affected region. other manifestations may include transient dysphagia, numbness or tingling of the face and lips, double vision, slurred speech, and dizziness.