A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a "brain attack."
A stroke happens when blood flow to a part of the brain is interrupted because a blood vessel in the brain is blocked or bursts open.
If blood flow is stopped for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing permanent damage.
There are two major types of stroke: ischemic stroke and hemorrhagic stroke.
Ischemic stroke occurs when a blood vessel that supplies blood to the brain is blocked by a blood clot. This may happen in two ways:
Ischemic strokes may result from clogged arteries, a condition called atherosclerosis. This may affect the arteries within the brain or the arteries in the neck that carry blood to the brain. Fat, cholesterol, and other substances collect on the wall of the arteries, forming a sticky substance called plaque. Over time, the plaque builds up. This often makes it hard for blood to flow properly, which can cause the blood to clot.
Ischemic strokes may also be caused by blood clots that form in the heart or other parts of the body. These clots travel through the blood and can get stuck in the small arteries of the brain. This is known as a cerebral embolism.
Certain drugs and medical conditions can make your blood more likely to clot and raise your risk for ischemic stroke. A common cause of ischemic stroke in people under age 40 is carotid dissection, or a tear in the lining of the carotid artery. The tear lets blood flow between the layers of the carotid artery. This causes narrowing of the carotid artery that is not due to plaque buildup.
Some ischemic strokes start out without any bleeding, and then bleeding into the damaged area occurs.
Hemorrhagic stroke occurs when a blood vessel in part of the brain becomes weak and bursts open, causing blood to leak into the brain. Some people have defects in the blood vessels of the brain that make this more likely. The flow of blood that occurs after the blood vessel ruptures damages brain cells.
High blood pressure is the number one risk factor for strokes. The following also increase your risk for stroke:
Certain medications make blood clots more likely, and therefore increase your chances for a stroke. Birth control pills can increase the chances of having blood clots, especially in woman who smoke and who are older than 35.
Men have more strokes than women. However, women have a higher risk of stroke during pregnancy and in the weeks immediately after pregnancy.
The following can increase the risk of bleeding into the brain, which makes you more likely to have a stroke:
For more information see: Stroke risk factors and prevention
The symptoms of stroke depend on what part of the brain is damaged. In some cases, a person may not even be aware that he or she has had a stroke.
Symptoms usually develop suddenly and without warning, or they may occur on and off for the first day or two. Symptoms are usually most severe when the stroke first happens, but they may slowly get worse.
A headache may occur, especially if the stroke is caused by bleeding in the brain. The headache:
Other symptoms depend on the severity of the stroke and what part of the brain is affected. Symptoms may include:
A complete physical and neurological exam should be performed. Your doctor will:
Tests can help your doctor determine the type, location, and cause of the stroke and rule out other disorders that may be responsible for the symptoms.
A stroke is a medical emergency. Immediate treatment can save lives and reduce disability. Call 911 or your local emergency number or seek immediate medical care at the first signs of a stroke.
It is very important for people who are having stroke symptoms to get to a hospital as quickly as possible. If the stroke is caused by a blood clot, a clot-busting drug may be given to dissolve the clot.
Most of the time, patients must reach a hospital within 3 hours after symptoms begin. Some people may be able to receive these drugs for up to 4 - 5 hours after symptoms begin.
Treatment depends on the severity and cause of the stroke. A hospital stay is required for most strokes.
TREATMENT IN THE HOSPITAL
Clot-busting drugs (thrombolytic therapy) may be used if the stroke is caused by a blood clot. Such medicine breaks up blood clots and helps restore blood flow to the damaged area. However, not everyone can receive this type of medicine.
Other treatments depend on the cause of the stroke:
Nutrients and fluids may be necessary, especially if the person has swallowing difficulties. These may be given through a vein (intravenously) or a feeding tube in the stomach (gastrostomy tube). Swallowing difficulties may be temporary or permanent.
Physical therapy, occupational therapy, speech therapy, and swallowing therapy will all begin in the hospital.
The goal of treatment after a stroke is to help the patient recover as much function as possible and prevent future strokes.
The recovery time and need for long-term treatment differs from person to person. Problems moving, thinking, and talking often improve in the weeks to months after a stroke. A number of people who have had a stroke will still continue to improve in the months or years after the stroke.
See: Stroke recovery for information about:
Additional support and resources are available from the American Stroke Association -- www.strokeassociation.org.
The outlook depends on the type of stroke, how much brain tissue is damaged, what body functions have been affected, and how quickly treatment is received. Recovery may occur completely, or there may be some permanent loss of function.
Over half of the people who have a stroke are able to function independently at home.
If treatment with clot-busting drugs is successful, the symptoms of a stroke may completely go away. However, patients do not often arrive at the hospital soon enough to receive these drugs, or there are complicating medical conditions that prevent their use.
People who have an ischemic stroke (stroke due to a blood clot) have a better chance of surviving than those who have a hemorrhagic stroke (stroke due bleeding in the brain).
The risk for a second stroke is highest over the first few weeks or months after the first stroke and then begins to lessen.
Stroke is a medical emergency that requires immediate treatment. Call your local emergency number (such as 911) if someone has symptoms of a stroke.
To help prevent a stroke:
Aspirin therapy (81 mg a day or 100 mg every other day) is recommended for stroke prevention in all men who have stroke risk factors, and in women under age 65 who are at risk for stroke, as long as the benefits outweigh the risks. It should be considered for women over age 65 only if their blood pressure is controlled and the benefit is greater than the risk of gastrointestinal bleeding and brain hemorrhage. Ask your doctor if aspirin is right for you.
Your doctor may also recommend aspirin therapy or another blood thinner if you have had a transient ischemic attack (TIA) or stroke in the past, or if you currently have:
A type of surgery called carotid endarterectomy may help prevent new strokes from occurring in persons with large blockages in their neck arteries.
See also: Stroke risk factors and prevention
Cerebrovascular disease; CVA; Cerebral infarction; Cerebral hemorrhage; Ischemic stroke; Stroke - ischemic; Cerebrovascular accident; Stroke - hemorrhagic