A stroke is a medical condition in which poor blood flow to the brain causes cell death. The main risk factor for link is high blood pressure. Prevention includes decreasing risk factors, surgery to open up the arteries to the brain in those with problematic carotid narrowingand warfarin in people with atrial fibrillation.
Inapproximately 6. Strokes can be classified into two major categories: ischemic and hemorrhagic. Bleeding can develop inside areas of ischemia, a condition known as "hemorrhagic transformation. In the s the World Health Organization defined stroke as a "neurological vadcular of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours",  although the word "stroke" is centuries old.
This definition was supposed to reflect the reversibility of tissue damage and was devised for the purpose, with the time frame of 24 hours being chosen arbitrarily. The hour limit divides stroke from transient ischemic attackwhich is a related syndrome of stroke symptoms that resolve completely within 24 hours.
In an ischemic stroke, blood supply to part of the brain is decreased, leading to dysfunction of the brain tissue in that area. There are four reasons why this might happen:. Cerebral vascular accidents are various classification systems for acute ischemic stroke. These four entities predict the extent of the stroke, the area of the brain that is affected, the underlying cause, and the prognosis.
Cum poti preveni un AVC daca ai trecut de 50 de ani
There are two main types of hemorrhagic stroke:  article source. The above two main types of hemorrhagic stroke are also two different forms of intracranial hemorrhagewhich is the accumulation of blood anywhere within the cranial vault ; but the other forms of intracranial hemorrhage, such as epidural hematoma bleeding between the skull and the dura materwhich is the thick outermost layer of the meninges that surround the brain and cwrebral hematoma bleeding in the subdural spaceare not considered "hemorrhagic strokes". Hemorrhagic strokes may cerebral vascular accidents on the background of alterations to the blood vessels in the brain, such as cerebral amyloid angiopathycerebral arteriovenous malformation and an intracranial aneurysmwhich can cause intraparenchymal or subarachnoid hemorrhage.
In addition vzscular neurological impairment, hemorrhagic strokes usually cause specific symptoms for instance, subarachnoid hemorrhage classically causes a severe headache known as a cerebral vascular accidents headache or reveal evidence of a previous head injury. Stroke symptoms typically start suddenly, over seconds to minutes, and in most cases do not progress further. The symptoms depend on the area of the brain affected. The more extensive the area of the brain affected, the more functions that are likely to be lost. Some forms of stroke can cause additional symptoms.
Ce dieta este indicata pentru a preveni accidentul vascular cerebral sau dupa un AVC?
For example, in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with a headacheapart from subarachnoid hemorrhage and cerebral venous thrombosis and occasionally intracerebral hemorrhage. Various systems have been proposed to increase recognition of stroke.]