What Is a Stroke?
A stroke happens when something changes how blood flows through the brain. Blood brings oxygen and nutrients to brain cells. If blood can’t flow to a part of the brain, cells that do not receive enough oxygen suffer and eventually die. If brain cells are without oxygen for only a short time, they can sometimes get better. But brain cells that have died can’t be brought back to life. So, someone who has had a stroke may have trouble speaking, thinking, or walking.
There are two major types of stroke. The most common kind, ischemic, is caused by a blood clot or the narrowing of a blood vessel (an artery) leading to the brain. This keeps blood from flowing into other parts of the brain and keeps needed oxygen and nutrients from reaching brain cells. Blockages that cause ischemic strokes stem from three conditions:
- Formation of a clot within a blood vessel of the brain or neck, called thrombosis
- Movement of a clot from another part of the body, such as from the heart to the neck or brain, called an embolism
- Severe narrowing of an artery (stenosis) in or leading to the brain, due to fatty deposits lining the blood vessel walls
In the second major kind of stroke, hemorrhagic, a broken blood vessel causes bleeding in the brain. This break in the vessel also stops oxygen and nutrients from reaching brain cells.
Sometimes the symptoms of a stroke last only a few minutes and then go away. That could be a transient ischemic attack (TIA), also called a mini-stroke. A TIA is a medical emergency. You should get medical help right away. If a TIA is not treated quickly, it could be followed within hours or days by a major disabling stroke.
Lower Your Risk of Stroke
Some risk factors for stroke, like age, race, and family history, can’t be controlled. But you can make changes to lower your risk of stroke. Talk to your doctor about what you can do. Even if you’re in perfect health, follow these suggestions:
- Control your blood pressure. Have your blood pressure checked often. If it is high, follow your doctor’s advice to lower it. Treating high blood pressure lowers the risk of both stroke and heart disease.
- Stop smoking. Smoking increases your risk for stroke. It’s never too late to quit.
- Control your cholesterol. If you have high cholesterol, work with your doctor to lower it. Cholesterol, a type of fat in the blood, can build up on the walls of your arteries. In time, this can block blood flow and lead to a stroke.
- Control your diabetes. Untreated diabetes can damage blood vessels and also leads to narrowed arteries and stroke. Follow your doctor’s suggestions for keeping diabetes under control.
- Eat healthy foods. Eat foods that are low in cholesterol and saturated fats. Include a variety of fruits and vegetables every day.
- Exercise regularly. Try to make physical activity a part of your everyday life. Do things you like; for example, take a brisk walk, ride a bicycle, or go swimming. Talk with your healthcare provider if you haven’t been exercising and you want to start a vigorous program or increase your physical activity. For more information on exercise and physical activity from the National Institute on Aging at NIH, visit www.nia.nih.gov/Go4Life.
If you have had a stroke in the past, it's important to reduce your risk of a second stroke. Your brain helps you recover from a stroke by drawing on body systems that now do double duty. That means a second stroke can be twice as bad.
Diagnosing and Treating Stroke
A doctor will diagnose a stroke based on symptoms, medical history, and medical tests such as a CT scan. A CT scan is a test that lets doctors look closely at pictures of the brain.
All strokes benefit from immediate medical treatment! But only people with ischemic stroke, the kind caused by a blood clot, can be helped by a drug called t-PA (tissue-plasminogen activator). This drug breaks up blood clots and can greatly lessen the damage caused by an ischemic stroke. Starting treatment with t-PA within 3 hours after an ischemic stroke is important to recovery. To be evaluated and receive treatment, patients need to get to the hospital within 60 minutes. Getting to a hospital right away allows time for a CT scan of the brain. This scan will show whether the clot-busting medicine is the right treatment choice.
With stroke, treatment depends on the stage of the disease. There are three treatment stages for stroke: prevention, therapy immediately after stroke, and rehabilitation after stroke. Stroke therapies include medications, surgery, and rehabilitation.
Medication or drug therapy is the most common treatment for stroke. The most popular kinds of drugs to prevent or treat stroke are antithrombotics--which include antiplatelet agents and anticoagulants--and thrombolytics. Thrombolytic drugs, like t-PA, halt the stroke by dissolving the blood clot that is blocking blood flow to the brain. Antithrombotics prevent the formation of blood clots that can become stuck in an artery of the brain and cause strokes.
Surgery and vascular procedures can be used to prevent stroke, treat stroke, or repair damage to the blood vessels or malformations in and around the brain. These include angioplasty, stenting, and carotid endarterectomy.
What Happens After a Stroke?
A stroke can cause a variety of health problems. How a stroke affects a person depends on which part of the brain is damaged.
Someone who has had a stroke might be paralyzed or have weakness, usually on one side of the body. He or she might have trouble speaking or using words. There could be swallowing problems. There might be pain or numbness.
Stroke may cause problems with thinking, awareness, attention, learning, judgment, and memory. Someone who has had a stroke might feel depressed or find it hard to control emotions. Post-stroke depression may be more than general sadness resulting from the stroke incident. It is a serious behavioral problem that can hamper recovery and rehabilitation and may even lead to suicide.
There are many different ways to help people get better after a stroke. Many treatments start in the hospital and continue at home. Drugs and physical therapy can help improve balance, coordination, and problems such as trouble speaking and using words. Occupational therapy can make it easier to do things like taking a bath or cooking.
Some people make a full recovery soon after a stroke. Others take months or even years. But, sometimes the damage is so serious that therapy cannot really help.
Learn about rehabilitation after stroke.
For More Information on Stroke
National Library of Medicine