Frequently Asked Questions About Stroke
Q. What is cerebrovascular disease?
A. Cerebrovascular disease is one of the most devastating and misunderstood epidemics of our time. More than 700,000 American suffer a major cerebrovascular event - most likely a stroke - each year.
Q. Why does the brain need blood?
A. Blood supplies the body with nutrients and oxygen. The brain, which controls every action your body makes from walking to and talking to moving your arm and breathing, receives about 20 percent of the blood that flows through your entire body.
Q. What is a stroke?
A. Stroke is an abrupt interruption of constant blood flow to the brain that causes loss of neurological function. The interruption of blood flow can be caused by a blockage, leading to the more common ischemic stroke, or by bleeding in the brain, leading to the more deadly hemorrhagic stroke.
In any event, proper blood flow and oxygen must be restored to the brain as soon as possible. Without oxygen and important nutrients, the affected brain cells are either damaged or die within a few minutes. Once brain cells die, they cannot be regrown or revitalized.
Q. How common is stroke?
A. Stoke is the third leading cause of death in the United States and the number one cause of disability, with more than 3,000,000 people currently living with physical and mental impairment from brain damage caused by stroke. On average, someone in the United States suffers a stroke every 53 seconds and every 3.3 minutes someone dies of one.
Q. Are some people more likely to suffer a stroke than others are?
A. Although stroke can strike anyone, the risk of stroke doubles with each decade lived after age 50. The incidence of stroke is also greater among males, African Americans, and individuals with a history of heart disease, diabetes and cerebrovascular disease.
Q. Is there anything that I can do to prevent a stroke?
A. Modifiable risk factors for stroke are easily recognizable and treatable and, if managed properly, can reduce a patient's risk of stroke more than ten-fold. Following are modifications you can make to your lifestyle to reduce your risk for stroke:
1) Control your blood pressure. High blood pressure is the leading cause of both ischemic and hemorrhagic stroke and should be treated and kept to a low level of 140/90.
2) Stop smoking. Cigarette smoking doubles your chances for stroke.
3) Eat a healthy diet and exercise regularly. Obesity increases your chances of suffering hypertension and high blood cholesterol, a factor in developing carotid stenosis.
4) Promptly report warning signs to your doctors. Untreated carotid stenosis drastically increases your risk of suffering a thrombolitic stroke.
Q. What are the different types of strokes?
A. Most strokes are caused by a blood clot or a narrowing of a blood vessel (artery) leading to the brain, known as ichemic stroke. Other strokes are caused by a hemorrhage (bleeding) from an artery in the brain itself, known as hemorrhagic stroke.
Q. What is an ischemic stroke?
A. An ischemic stroke is caused by atherosclerosis, or the build up of cholesterol-containing fatty deposits called plaque. As the plaque roughens the inside of an artery and the vessel begins to narrow, the flow of oxygen and nutrients to the brain becomes disrupted.
A thrombolic stroke is the most common form of ischemic stroke. It occurs when a clot, or thrombus, develops in arteries that have been narrowed by fatty buildup that has formed on the inner layers of the artery walls. The clot, when coupled with the narrowed arteries, combines to block blood from flowing.
If the blockage has come from somewhere else, most likely the heart, it is called an embolic stroke. During an embolic stroke, a piece of thrombus breaks lose and lodges in an artery leading to the brain, thereby blocking blood flow. Exactly where in the artery the blockage occurs determines which part of the brain will be affected.
Q. What is a hemorrhagic stroke?
A. A hemorrhagic stroke occurs when a blood vessel in the brain leaks or ruptures and blood spills into the surrounding brain tissue, thereby preventing needed oxygen from reaching the brain. The most common form of hemorrhagic stroke, known as a subarachnoid hemorrhage (SAH), occurs when an aneurysm that has weakened over time balloons and suddenly bursts, forcing blood into the area surrounding the brain (subarachnoid space). Each year, more than 30,000 Americans have a SAH and, of those, 30 percent die before reaching medical facilities.
Another form of hemorrhagic stroke is intracerebral hemorrhage (ICH), which occurs when a vascular lesion forms on a blood vessel. The brain tissue is usually damaged by the initial bleed and brain cells receive secondary injury as blood flow remains irregular and ischemia sets in.
Q. Which type of stroke - ischemic or hemorrhagic - is more common?
A. Approximately 84 percent of strokes are ischemic and 16 percent are hemorrhagic. Although hemorrhagic strokes are less common, they result in a higher morbidity rate (about 50 percent) than ischemic strokes (about 20 percent).
Q. What are the warning signs of stroke?
A. Stroke is generally characterized by sudden visual disturbances, including blocked or loss of vision in one eye, blurry vision or "graying"; weakness, numbness or clumsiness in one arm or hand; language problems, including slurred speech; facial droop or weakness; dizziness or stumbling; or the abrupt onset of a severe headache.
Q. I know someone who experienced those symptoms and was fine a few hours later, is that possible?
A. Yes. This is known as a transient ischemic attack (TIA) and is one of the most prevalent and predicting warning signs of stroke. Symptoms for TIA are similar to traditional stroke symptoms and include visual disturbances, weakness or numbness and language difficulties. The symptoms are temporary and onset is abrupt, usually lasting between 2-25 minutes.
Q. What should I do if I think someone suffered a TIA?
A. If you suspect someone has suffered a TIA, seek immediate medical attention. It is very important that a TIA is recognized and the cause is determined in order to prevent a more devastating cerebrovascular event from occurring. Approximately 10 percent of patients who experience a TIA will suffer a stroke within 1 month and approximately 23 percent will suffer a stroke within one year. Determining the cause of the TIA is essential to preventing stroke.
Q. How are TIAs usually treated?
A. TIAs may be treated with anticoagulants or platelet inhibitors -- drugs commonly known as blood thinners -- or, if the underlying cause is the build-up of plaque in a carotid artery of the neck, a surgical procedure known as a carotid endarterectomy may be performed.
Q. What is carotid artery disease?
A. Carotid artery disease occurs when plaque builds up on the artery wall. This condition is called stenosis and is the leading cause of thrombolotic stroke. Early warning signs of stenosis can be detected by a primary care physician during a regular physical exam and include the presence of a carotid bruit or a difference in blood pressure in the right and left arms.
Q. How does a physician determine if a patient has stenosis and to what degree?
A. Several diagnostic tests can be used to determine a patient's degree of stenosis, including doppler ultrasound, MRI/MRA, and angiography. The determination of which test to use depends on the patients individual symptoms, risk factors and the services available in the patient's community.
Doppler ultrasound is a basic, non-invasive imaging test that visualizes arteries in the neck by using sound waves to determine the flow of blood through the artery. This test, which takes approximately 15-20 minutes, can help determine the degree of stenosis and the level of blood flow through the neck.
Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiogram (MRA) of the brain and carotid arteries will show a complete picture of the brain tissue and all of the arteries, including arteries in the brain. An MRI/MRA is a non-invasive procedure that takes approximately 1 hour.
Angiography is the most accurate test for determining the amount of stenosis in the carotid arteries, yet it is also the most expensive. During an angiography, a catheter is threaded up into the artery from the groin and contrast dye is injected into the artery. This test allows neurosurgeons to see the inside of the blood vessel in great detail.
Q. What are the best treatment options for a patient diagnosed with stenosis?
A. For patients with less than 50 percent stenosis, medical therapy is often prescribed. These treatments include anticoagulent drugs, like Warfin, and antiplatelet drugs, like aspirin, Ticlopidine and Plevix.. Patients with more than 50 percent stenosis often require a more aggressive approach including carotid endarterectomy and endovascular stenting.
Q. What is endovascular stenting?
A. A stent is a small, slotted, stainless steel tube is placed over an angioplasty balloon catheter and threaded up the artery to the area of the blockage. When the balloon is inflated, the stent expands, locks in place and forms a rigid support to hold the artery open. The stent remains in the artery permanently.
Q. How does endovascular stenting differ from a carotid endarterectomy?
A. A carotid endarterectomy is a surgical procedure in which the carotid artery is exposed and plaque is removed, thereby reducing the risk of a thrombus breaking off and interrupting blood flow to the brain. Patients are often hospitalized for 48 hours after the procedure. Complication rates for carotid endarterectomy are approximately 3 percent.
Q. Why does a patient sometimes need surgery when he/she has a blockage of the blood vessel in the neck that is not producing any symptoms?
A. In two scientific studies, it was found that patients who had greater than 70 percent stenosis, and underwent carotid endarterectomy, reduced their relative risk of stroke by 55 percent and patients with between 50 to 69 percent stenosis reduced their relative risk by 35 percent.
Q. Should stroke be treated as an emergency, just like a heart attack?
A. Yes, a stroke requires immediate medical care. Research shows that medical treatment during the first three hours after symptoms appear results in the best possible recovery.
Q. What will happen once the person reaches a hospital?
A. Doctors will monitor the patient's vital signs and perform a series of simple neurological tests to determine if the patient has suffered a stroke. If the doctor confirms that the patient has suffered a stroke, the next step is to pinpoint the cause and location so that treatment can begin.
Q. What type of tests might the neurosurgeon order?
A. There are a number of imaging tests that might be ordered to determine what, if any, damage has occurred, how it was caused and where it is located. They include:
1) Computerized Tomography (CT) scans take cross-sectional x-ray images of selected parts of the body. The picture it records can be used to help determine is a stroke is ischemic or hemorrhagic in nature, as well as pinpoint its location.
2) Magnetic Resonance Imaging (MRI) uses magnetic fields and radio-frequency pulses to take images of internal body parts and provide a clear picture of bleeding, blockages and blood vessel malformations.
3) Positron Emission Tomography (PET) scans create computer-generated x-ray images of the brain by means of radioactive isotopes injected into the body. PET scans show how the brain is functioning and help determine whether blood vessels are blocked or if certain areas of the brain are damaged.
4) Electroencephalogram (EEG) tests the brain's activity by detecting electrical impulses transmitted and received by the brain.
Q. Do patients ever get better after suffering a stroke?
A. Surprisingly, many patients do show improvements in their symptoms either spontaneously or after rehabilitation. While this is not universal, it occurs often enough that one should not give up on a patient until the outcome is apparent.
Q. How are stroke victims physically effected?
A. Stroke can be very disabling, and often results in paralysis, weakness or loss of sensation, and balance, coordination and communication problems.
Q. Where can I get more information about stroke?
A. If you have more questions, please consult your healthcare provider and ask them to recommend a neurosurgeon for consultation, or visit the AANS Web site at http://www.neurosurgery.org/aans.
Note: The Annual Meeting press kit can be found in the Media Center Section of the AANS Web site at: http://www.neurosurgery.org/aans.
American Association of Neurological Surgeons
22 S. Washington Street, Park Ridge, IL 60068
(847) 692-9500 Fax (847) 692-2589
Web site http://www.neurosurgery.org/aans
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