Cerebrovascular disease is a common cause of stroke, the third leading cause of death in the United States. A stroke occurs when blood supply to the brain is interrupted. Strokes are sometimes called "brain attacks" because what happens to the brain during a stroke is similar to what happens to the heart during a heart attack. The lack of bloodflow deprives critical brain cells of oxygen and nutrients. The length of time of the inadequate bloodflow will determine the extent and permanence of the damage to the brain. Show
There are two kinds of stroke: ischemic stroke and hemorrhagic stroke. Ischemic stroke is the most common type of stroke. It results from clogging of the arteries,through a process called atherosclerosis, or hardening of the arteries, and death of brain cells. Hemorrhagic stroke occurs when a blood vessel in the brain bursts, leading to bleeding in the brain. Risk factors, diagnosis and treatment of cerebrovascular diseaseMany things related to ischemic stroke, such as who is at risk, the symptoms and how the problem is diagnosed and treated, depend on underlying causes -- whether it be carotid artery disease, vertebrobasilar insufficiency or something else. In the case of hemorrhagic stroke, surgery may be required to remove pooled blood from the brain and repair the damaged blood vessel. UC Davis Health neurosurgeons and neurointerventionalists provide care for hemorrhagic strokes. Think of a stroke as a "brain attack"— it is an emergency! When symptoms appear, call 911 immediately; every minute counts. A stroke occurs when the brain is deprived of blood supply. Without oxygen, brain cells die. Depending on the area affected, a person may have problems speaking, walking, seeing, or thinking. A stroke may result in permanent brain damage or death. If the stroke is caused by a blood clot, a clot-busting drug or retrieval device may be used to restore blood flow. Blood supply of the brainTo understand stroke, it is helpful to know how blood circulates to the brain (see Anatomy of the Brain). Blood is pumped from the heart and carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries (Fig. 1). The internal carotid arteries supply the anterior (front) areas and the vertebral arteries supply the posterior (back) areas of the brain. After passing through the skull, the right and left vertebral arteries join together to form a single basilar artery. The basilar artery and the internal carotid arteries communicate with each other in a ring at the base of the brain called the Circle of Willis. The middle cerebral artery is the artery most often blocked during a stroke. Figure 1. A stroke is a sudden interruption of the blood supply to the brain. The middle cerebral artery is most often blocked during a stroke. The internal carotid arteries form the anterior (green) circulation and the vertebral / basilar arteries supply the posterior (red) circulation of the brain. The two systems connect at the Circle of Willis (circle).What is a stroke?Stroke is a sudden interruption of the blood supply to the brain. Most strokes are caused by an abrupt blockage of an artery (ischemic stroke). Other strokes are caused by bleeding into brain tissue when a blood vessel bursts (hemorrhagic stroke). The effects of a stroke depend on the severity and which area of the brain is injured. Strokes may cause sudden weakness, loss of sensation, or difficulty with speaking, seeing, or walking. Since different parts of the brain control different areas and functions, it is usually the area immediately surrounding the stroke that is affected. Hemorrhagic strokes have a much higher death rate than ischemic strokes. Ischemic stroke - (most common - 87% of cases) is caused by a blockage of an artery from a blood clot (thrombus) or from clogged blood vessels due to atherosclerosis (hardening of the arteries). In atherosclerosis, cholesterol plaques are deposited within the walls of the arteries, narrowing the inside diameter of the artery (Fig. 2A). As the artery narrows, less blood is able to pass to the brain, and blood pressure increases to meet the demands of the body. The normally smooth inner wall of the artery is now roughed with plaque deposits, causing blood cells to build up and form clots (Fig. 2B). Clot build-up usually occurs in large blood vessels of the neck and base of the brain. Figure 2. Types of stroke include: A) ischemic stroke due to build-up of atherosclerotic plaques, B) embolic stroke from blood clots that stick to plaques and break off, C) hemorrhagic stroke from bleeding into the subarachnoid space, and D) intracerebral hemorrhage from tiny vessel ruptures due to hypertension.Embolic stroke - is caused when a clot breaks off from the artery wall it becomes an embolus, which can travel farther down the bloodstream to block a smaller artery. Emboli usually come from the heart, where different diseases cause clot formation. Hemorrhagic stroke - (less common - 13% of cases) is caused by the rupture or leaking of an artery either within or around the brain. It can occur when a weakened blood vessel ruptures, releasing blood into the space surrounding the brain. This is called a subarachnoid hemorrhage (SAH). It can be caused by a ruptured aneurysm (Fig. 2C), arteriovenous malformation (AVM), or head trauma. Bleeding within the brain tissue itself is known as an intracerebral hemorrhage (ICH) and is primarily caused by hypertension (Fig. 2D). Hypertension is an elevation of blood pressure which may cause tiny arteries to burst inside the brain. What are the symptoms?Stroke symptoms may occur alone or in combination and may last a few minutes or several hours. If you or someone around you notices one or more of these warning signs, seek immediate medical attention. Poor public knowledge of stroke warning signs and risk factors limits effective stroke intervention and prevention. Even if stroke symptoms disappear, they are a clear warning that a larger stroke may follow.
If you notice signs of a stroke, think "FAST" and do the following:
Transient Ischemic Attacks (TIAs) What are the causes?Risk factors you can't modify
Risk factors you can modify
How is a diagnosis made?When an individual is brought to the emergency room with an apparent stroke, the doctor will learn as much about the patient symptoms, current and previous medical problems, current medications, and family history. The doctor also will perform a physical exam. If the patient can't communicate, a family member or friend will be asked to provide this information. Diagnostic tests are used to help the doctors determine what is the cause and how to treat the stroke.
What treatments are available?Treatment for stroke depends on whether the patient is diagnosed with an ischemic or hemorrhagic stroke. In either case the person must get to a hospital immediately for the treatments to work. Ischemic stroke treatments can be divided into emergency treatments to reverse a blockage and preventive treatments to prevent stroke. Emergency procedures
Preventive procedures
Hemorrhagic stroke treatment focuses on stopping the bleeding. Clot buster drugs TPA also can be delivered right at the clot site in a procedure called intra-arterial thrombolysis. In this method the tPA drug does not have to travel through your entire body before reaching the clot. A doctor called a neuro-interventionalist performs this procedure during an angiogram. A very small catheter is inserted into an artery in the groin and guided through the bloodstream up to the brain where the clot is located. The tPA drug is then released to dissolve the clot. The doctor also pushes the catheter back and forth through the clot to help break it up. Clot retrieval devices
Studies have shown that each of these devices is more likely to open a blocked artery than the clot buster drug alone and that patients with large-artery strokes are more likely to improve with this treatment. Clot retrieval may be effective up to 6 hours after the onset of the stroke [3]. More recently, trials have shown that, for a small group of patients who wake up with stroke symptoms or are between 6 to 24 hours after onset, clot retrieval may still be effective. If specialized imaging shows that the territory of the stroke is small, removing the clot can prevent the stroke from getting larger and more severe [4]. Still, the earlier treatment begins the better. Blood thinners Angioplasty Carotid endarterectomy RecoveryEach person's mental and physical deficits are unique. Someone who has a small stroke may experience only minor deficits, such as weakness of an arm or leg, while someone who has a larger stroke may be left paralyzed on one side or lose his or her ability to speak. Some deficits may disappear over time with healing and therapy. The recovery process is long, and regaining function may take months or years. Rehabilitation professionals can help set up a treatment plan and help loved ones understand the patient's needs for assistance with daily living activities.
Preventing another strokeThe link between cardiovascular health and stroke is inseparable. Of the 700,000 strokes suffered in the United States each year, about 200,000 are recurrent attacks. If you are at risk:
Clinical trialsClinical trials are research studies in which new treatments—drugs, diagnostics, procedures, and other therapies—are tested in people to see if they are safe and effective. Research is always being conducted to improve the standard of medical care. Information about current clinical trials, including eligibility, protocol, and locations, is found on the web. Studies can be sponsored by the National Institutes of Health (see Clinicaltrials.gov) as well as private industry and pharmaceutical companies (see Centerwatch.com). Sources & linksIf you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100. Sources
Links Glossaryaneurysm: a bulge or weakening of an arterial wall. angioplasty: reopening of a narrowed or blocked blood vessel by inflation of a balloon-tip catheter from inside the artery. atherosclerosis: a degenerative disease of the arteries in which fatty plaques and scar tissue form on the inner walls and block the free flow of blood. arteriovenous malformation (AVM): abnormality of blood vessels where arteries shunt directly into veins with no intervening capillary bed. emboli: a blood clot or other substance such as air or fat, which is carried in the bloodstream from another site until it blocks a blood vessel. embolization: inserting material, coil or glue, into an aneurysm so blood can no longer flow through it. infarct: an area of dead tissue caused by a blockage of its blood supply. intracerebral hemorrhage (ICH): bleeding directly into the brain tissue; may cause a stroke. ischemia: a low oxygen state usually due to obstruction of the arterial blood supply or inadequate blood flow leading to hypoxia in the tissue. subarachnoid hemorrhage: bleeding in the space surrounding the brain; may cause a stroke. tissue plasminogen activator (tPA): a thrombolytic "clot-buster" drug used to reduce the severity of ischemic stroke if given within three hours of stroke onset; can be given intravenously or by arterial catheter, but not by mouth. thrombus: a blood clot. thrombolysis: to break down or dissolve a clot. transient ischemic attack (TIA): a “mini” stroke caused when blood flow to the brain is temporarily interrupted and then restored; causes no permanent brain damage. What is it called when you have lack of blood flow to the brain?Cerebral vascular insufficiency (not enough blood flow to the brain) increases the risk of stroke and is a major cause of neurologic death and disability worldwide. It is typically caused by atherosclerosis (buildup of fats, cholesterol and other substances that clog arteries that supply blood to the brain).
What is lack of blood supply called?Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive).
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