cerebrovascular-accident

stroke

or cerebrovascular accident (CVA)

Sudden impairment of brain function due to hypoxia, which may cause death of brain tissue. Hypertension, atherosclerosis, smoking, high cholesterol, diabetes, old age, atrial fibrillation, and genetic defects are risk factors. Strokes due to thrombosis (the most common cause), embolism, or arterial spasm, which cause ischemia (reduced blood supply), must be distinguished from those due to hemorrhage (bleeding), which are usually severe and often fatal. Depending on its site in the brain, a stroke's effects may include aphasia, ataxia, local paralysis, and/or disorders of one or more senses. A massive stroke can produce one-sided paralysis, inability to speak, coma, or death within hours or days. Anticoagulants can arrest strokes caused by clots but worsen those caused by bleeding. If the cause is closure of the major artery to the brain, surgery may clear or bypass the obstruction. Rehabilitation and speech therapy should begin within two days to retain and restore as much function as possible, since survivors may live many more years. Transient ischemic attacks (“mini strokes”), with short-term loss of function, result from blockage of blood flow to small areas. They tend to recur and may worsen, leading to multi-infarct dementia or stroke.

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Cerebrovascular disease is a group of brain dysfunctions related to disease of blood vessels supplying the brain. Hypertension is the most important cause that damages the blood vessel lining endothelium exposing the underlying collagen where platelets aggregate to initiate a repairing process which is not always complete and perfect. Sustained hypertension permanently changes the architecture of the blood vessels making them narrow, stiff, deformed and uneven which are more vulnerable to fluctuations of blood pressure. A fall in blood pressure during sleep can lead to marked reduction in blood flow in the narrowed blood vessels causing ischemic stroke in the morning whereas a sudden rise in blood pressure can cause tearing of the blood vessels causing intracranial hemorrhage during excitation at daytime. Primarily people who are elderly, diabetic, smoker, or have ischemic heart disease, have cerebrovascular disease. All diseases related to artery dysfunction can be classified under a disease as known as Macrovascular disease. This is a simplistic study by which arteries are blocked by fatty deposits or by a blood clot. The results of cerebrovascular disease can include a stroke, or even sometimes a hemorrhagic stroke. Ischemia or other blood vessel dysfunctions can affect one during a cerebrovascular accident.

Pathophysiology and causes

In a healthy, anatomical structure of the body, the cartoid arteries form the main blood supply to the brain. Following a stroke, voluntary control of the muscles may be lost, depending on the type of stroke the victim is encountering. Another form of cerebrovascular disease includes aneurysms. In females with defective collagen, the weak branching points of arteries give rise to protrusions with a very thin covering of endothelium that can tear to bleed easily with minimal rise of blood pressure. This can also occur with defective capillaries by tissue cholesterol deposition especially in hypertensive subjects with or without dyslipidemia. If bleeding can occur in this process, the resulting effect is a hemorrhagic stroke in the form of subarachnoid hemorrhage, intracerebral hemorrhage or both. Strokes can also result from embolism, or a ruptured blood vessel. Embolism blocks small arteries within the brain, causing dysfunction to occur. Spontaneous rupture of a blood vessel in the brain causes a hemorrhagic stroke.

In the main structure, the carotid arteries overspread the majority of the cerebrum. The common carotid artery divides into the internal and the external artoid arteries. The internal carotid artery becomes the anterior cerebral artery and the middle central artery. The ACA transmits blood to the frontal parietal and a small part of the occipital lobe. The MCA is the largest branch of the internal carotid artery. From the Basillar artery are two posterior cerebral arteries. Branches of the Basillar and PCA supply the occipital lobe, brain stem, and the cerebellum.

Ischemia is the loss of blood flow to the focal region of the brain. The beginning process of this is quite rapid. The duration of a stroke is usually two to fifteen minutes. One side of the face, hand, or arm may swell up. During this time, you may lose conscious control and faint. Brain deficits may improve over a maximum of 72 hrs. Deficits, as stated before, do not resolve in all cases. The neurological recovery period includes- stable to improving brain function. Stable is the period by which neither nutrient supply is regained, nor is it lost. Improving, depending on a hospital code, generally means that the arteries gain control and blood flow functions consistently within the brain. The cartoid arteries connect to the vertebral arteries. These branch off into your cerebellar and posterior meningenial arteries, which supply the back of your brain. It is significant that one maintains a healthy and balanced diet in order to prevent cerebrovascular disease.

Also, during ischemia, interneurons weaken, causing an insufficient amount to perform vital functions to be present. The neuroglis become congested or maintain loss during a cerebrovascular accident. If impulse amount ceases, then life itself will cease and the victim may enter the stage of clinical death. Neural pathways weaken, therefore decreasing action potential. The neural arc, which in general, consists of sensory and motor neurons weaken as well. The muscles become paralyzed in some cases for life. Paralysis also includes the weakening of the receptors in the body, unless improvement is made. Cerebrovascular damage to the brain is what makes it difficult for receptors to receive the impulse and transmit it of a neuron. This chemical reaction is then transmitted creating a poor reflex to the body. The meninges that also protect the brain and spinal cord are deeply weakened, allowing the victim to suffer vast transmission of diseases or unstable growth or maintenance if the victim is not in resting position.

During the stage of paralysis, the spinal tracts do not have much to do with the enduring condition of cerebrovascular disease, either, in time may shorten a victim's life whom is suffering because the nutrient supply is weakened in transmission during cerebrovascular disease. Descending and ascending tracts will generally be cut off during cerebrovascular disease, which conducts impulses down from the cord of the brain. This is known as anesthesia in a minor case.

In a healthy body, the cerebrospinal fluid may also weaken the cortoid plexus, into a network of brain capillaries. Hydrocephalus is one of the current modern day treatments which include inserting a hollow tube through a blocked channel so the CSF can be used to be drained to another portion of the body. The dermatomes are a skin surface area which is regulated by the spinal cord. During a stroke, these may be damaged.

Symptoms

A cerebrovascular accident is apparent if the victim displays the following symptoms: dizziness, nausea, vomiting, severe headaches, head pressure, and the numbness within the limbs, slurred speech, vision loss, loss of coordination and the ability to walk. Hemorrhagic strokes may require surgery to relieve the pressure within the brain. Another treatment, endovascular treatment, requires inserting a tube into the major artery.

TIA

A transient ischemic attack leaves little to no permanent damage within the brain. The symptoms of this include facial weakness, visual impairment, loss of coordination, or balance and a sudden headache. A doctor can detect the disorders with a stethoscope. Severe blockage of the arteries to the brain is known as carotid stenosis. This generally results from high head trauma.

Epidemiology

Cerebrovascular disease generally affects those with diabetes and whose blood pressure is too high. However, treatment does include medications such as vitamin supplication, and tranquilizers. The discovery is unsure, for there is a wide variety of the types of the cerebrovascular diseases, but is classified under artery-vein diseases of the brain.

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