Stroke

A stroke occurs if the flow of oxygen-rich blood to a portion of the brain is blocked. Without oxygen, brain cells start to die after a few minutes. Sudden bleeding in the brain also can cause a stroke if it damages brain cells.

If brain cells die or are damaged because of a stroke, symptoms occur in the parts of the body that these brain cells control. Examples of stroke symptoms include sudden weakness; paralysis or numbness of the face, arms, or legs (paralysis is an inability to move); trouble speaking or understanding speech; and trouble seeing.

A stroke is a serious medical condition that requires emergency care. A stroke can cause lasting brain damage, long-term disability, or even death.

If you think you or someone else is having a stroke, call 9–1–1 right away. Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room. During a stroke, every minute counts.

Overview

The two main types of stroke are ischemic (is-KE-mik) and hemorrhagic (hem-ah-RAJ-ik). Ischemic is the more common type of stroke.

An ischemic stroke occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Blood clots often cause the blockages that lead to ischemic strokes.

A hemorrhagic stroke occurs if an artery in the brain leaks blood or ruptures (breaks open). The pressure from the leaked blood damages brain cells. High blood pressure and aneurysms (AN-u-risms) are examples of conditions that can cause hemorrhagic strokes. (Aneurysms are balloon-like bulges in an artery that can stretch and burst.)

Another condition that’s similar to a stroke is a transient ischemic attack, also called a TIA or “mini-stroke.” A TIA occurs if blood flow to a portion of the brain is blocked only for a short time. Thus, damage to the brain cells isn’t permanent (lasting).

Like ischemic strokes, TIAs often are caused by blood clots. Although TIAs are not full-blown strokes, they greatly increase the risk of having a stroke. If you have a TIA, it’s important for your doctor to find the cause so you can take steps to prevent a stroke.

Both strokes and TIAs require emergency care.

Outlook

Stroke is a leading cause of death in the United States. Many factors can raise your risk of having a stroke. Talk with your doctor about how you can control these risk factors and help prevent a stroke.

If you have a stroke, prompt treatment can reduce damage to your brain and help you avoid lasting disabilities. Prompt treatment also may help prevent another stroke.

Researchers continue to study the causes and risk factors for stroke. They’re also finding new and better treatments and new ways to help the brain repair itself after a stroke.

Ischemic Stroke

An ischemic stroke occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Blood clots often cause the blockages that lead to ischemic strokes.

The two types of ischemic stroke are thrombotic (throm-BOT-ik) and embolic (em-BOL-ik). In a thrombotic stroke, a blood clot (thrombus) forms in an artery that supplies blood to the brain.

In an embolic stroke, a blood clot or other substance (such as plaque, a fatty material) travels through the bloodstream to an artery in the brain. (A blood clot or piece of plaque that travels through the bloodstream is called an embolus.)

With both types of ischemic stroke, the blood clot or plaque blocks the flow of oxygen-rich blood to a portion of the brain.

Ischemic Stroke

The illustration shows how an ischemic stroke can occur in the brain. If a blood clot breaks away from plaque buildup in a carotid (neck) artery, it can travel to and lodge in an artery in the brain. The clot can block blood flow to part of the brain, causing brain tissue death.

Hemorrhagic Stroke

A hemorrhagic stroke occurs if an artery in the brain leaks blood or ruptures (breaks open). The pressure from the leaked blood damages brain cells.

The two types of hemorrhagic stroke are intracerebral (in-trah-SER-e-bral) and subarachnoid (sub-ah-RAK-noyd). In an intracerebral hemorrhage, a blood vessel inside the brain leaks blood or ruptures.

In a subarachnoid hemorrhage, a blood vessel on the surface of the brain leaks blood or ruptures. When this happens, bleeding occurs between the inner and middle layers of the membranes that cover the brain.

In both types of hemorrhagic stroke, the leaked blood causes swelling of the brain and increased pressure in the skull. The swelling and pressure damage cells and tissues in the brain.

Hemorrhagic Stroke

The illustration shows how a hemorrhagic stroke can occur in the brain. An aneurysm in a cerebral artery breaks open, which causes bleeding in the brain. The pressure of the blood causes brain tissue death.

• Brain attack
• Cerebrovascular accident (CVA)
• Hemorrhagic stroke (includes intracerebral hemorrhage and subarachnoid hemorrhage)
• Ischemic stroke (includes thrombotic stroke and embolic stroke)

A transient ischemic attack sometimes is called a TIA or mini-stroke. A TIA has the same symptoms as a stroke, and it increases your risk of having a stroke.

Ischemic Stroke and Transient Ischemic Attack

An ischemic stroke or transient ischemic attack (TIA) occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Many medical conditions can increase the risk of ischemic stroke or TIA.

For example, atherosclerosis (ath-er-o-skler-O-sis) is a disease in which a fatty substance called plaque builds up on the inner walls of the arteries. Plaque hardens and narrows the arteries, which limits the flow of blood to tissues and organs (such as the heart and brain).

Plaque in an artery can crack or rupture (break open). Blood platelets (PLATE-lets), which are disc-shaped cell fragments, stick to the site of the plaque injury and clump together to form blood clots. These clots can partly or fully block an artery.

Plaque can build up in any artery in the body, including arteries in the heart, brain, and neck. The two main arteries on each side of the neck are called the carotid (ka-ROT-id) arteries. These arteries supply oxygen-rich blood to the brain, face, scalp, and neck.

When plaque builds up in the carotid arteries, the condition is called carotid artery disease. Carotid artery disease causes many of the ischemic strokes and TIAs that occur in the United States.

An embolic stroke (a type of ischemic stroke) or TIA also can occur if a blood clot or piece of plaque breaks away from the wall of an artery. The clot or plaque can travel through the bloodstream and get stuck in one of the brain’s arteries. This stops blood flow through the artery and damages brain cells.

Heart conditions and blood disorders also can cause blood clots that can lead to a stroke or TIA. For example, atrial fibrillation (A-tre-al fi-bri-LA-shun), or AF, is a common cause of embolic stroke.

In AF, the upper chambers of the heart contract in a very fast and irregular way. As a result, some blood pools in the heart. The pooling increases the risk of blood clots forming in the heart chambers.

An ischemic stroke or TIA also can occur because of lesions caused by atherosclerosis. These lesions may form in the small arteries of the brain, and they can block blood flow to the brain.

Hemorrhagic Stroke

Sudden bleeding in the brain can cause a hemorrhagic stroke. The bleeding causes swelling of the brain and increased pressure in the skull. The swelling and pressure damage brain cells and tissues.

Examples of conditions that can cause a hemorrhagic stroke include high blood pressure, aneurysms, and arteriovenous (ar-TEER-e-o-VE-nus) malformations (AVMs).

"Blood pressure" is the force of blood pushing against the walls of the arteries as the heart pumps blood. If blood pressure rises and stays high over time, it can damage the body in many ways.

Aneurysms are balloon-like bulges in an artery that can stretch and burst. AVMs are tangles of faulty arteries and veins that can rupture within the brain. High blood pressure can increase the risk of hemorrhagic stroke in people who have aneurysms or AVMs.

Certain traits, conditions, and habits can raise your risk of having a stroke or transient ischemic attack (TIA). These traits, conditions, and habits are known as risk factors.

The more risk factors you have, the more likely you are to have a stroke. You can treat or control some risk factors, such as high blood pressure and smoking. Other risk factors, such as age and gender, you can’t control.

The major risk factors for stroke include:

• High blood pressure. High blood pressure is the main risk factor for stroke. Blood pressure is considered high if it stays at or above 140/90 millimeters of mercury (mmHg) over time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher.
• Diabetes. Diabetes is a disease in which the blood sugar level is high because the body doesn’t make enough insulin or doesn’t use its insulin properly. Insulin is a hormone that helps move blood sugar into cells where it’s used for energy.
• Heart diseases. Ischemic heart disease, cardiomyopathy, heart failure, and atrial fibrillation can cause blood clots that can lead to a stroke.
• Smoking. Smoking can damage blood vessels and raise blood pressure. Smoking also may reduce the amount of oxygen that reaches your body’s tissues. Exposure to secondhand smoke also can damage the blood vessels.
• Age and gender. Your risk of stroke increases as you get older. At younger ages, men are more likely than women to have strokes. However, women are more likely to die from strokes. Women who take birth control pills also are at slightly higher risk of stroke.
• Race and ethnicity. Strokes occur more often in African American, Alaska Native, and American Indian adults than in white, Hispanic, or Asian American adults.
• Personal or family history of stroke or TIA. If you’ve had a stroke, you’re at higher risk for another one. Your risk of having a repeat stroke is the highest right after a stroke. A TIA also increases your risk of having a stroke, as does having a family history of stroke.
• Brain aneurysms or arteriovenous malformations (AVMs). Aneurysms are balloon-like bulges in an artery that can stretch and burst. AVMs are tangles of faulty arteries and veins that can rupture (break open) within the brain. AVMs may be present at birth, but often aren’t diagnosed until they rupture.

Other risk factors for stroke, many of which of you can control, include:

• Alcohol and illegal drug use, including cocaine, amphetamines, and other drugs
• Certain medical conditions, such as sickle cell disease, vasculitis (inflammation of the blood vessels), and bleeding disorders
• Lack of physical activity
• Overweight and Obesity
• Stress and depression
• Unhealthy cholesterol levels
• Unhealthy diet
• Use of nonsteroidal anti-inflammatory drugs (NSAIDs), but not aspirin, may increase the risk of heart attack or stroke, particularly in patients who have had a heart attack or cardiac bypass surgery. The risk may increase the longer NSAIDs are used. Common NSAIDs include ibuprofen and naproxen.

Following a heart-healthy lifestyle can lower the risk of stroke. Some people also may need to take medicines to lower their risk. Sometimes strokes can occur in people who don’t have any known risk factors.

Taking action to control your risk factors can help prevent or delay a stroke. If you’ve already had a stroke. Talk to your doctor about whether you may benefit from aspirin primary prevention, or using aspirin to help prevent your first stroke. The following heart-healthy lifestyle changes can help prevent your first stroke and help prevent you from having another one.

• Be physically active. Physical activity can improve your fitness level and health. Talk with your doctor about what types and amounts of activity are safe for you.
• Don’t smoke, or if you smoke or use tobacco, quit. Smoking can damage and tighten blood vessels and raise your risk of stroke. Talk with your doctor about programs and products that can help you quit. Also, secondhand smoke can damage the blood vessels.
• Aim for a healthy weight. If you’re overweight or obese, work with your doctor to create a reasonable weight loss plan. Controlling your weight helps you control risk factors for stroke.
• Make heart-healthy eating choices. Heart-healthy eating can help lower your risk or prevent a stroke.
• Manage stress. Use techniques to lower your stress levels.

If you or someone in your family has had a stroke, be sure to tell your doctor. By knowing your family history of stroke, you may be able to lower your risk factors and prevent or delay a stroke. If you’ve had a transient ischemic attack (TIA), don’t ignore it. TIAs are warnings, and it’s important for your doctor to find the cause of the TIA so you can take steps to prevent a stroke.

The signs and symptoms of a stroke often develop quickly. However, they can develop over hours or even days.

The type of symptoms depends on the type of stroke and the area of the brain that’s affected. How long symptoms last and how severe they are vary among different people.

Signs and symptoms of a stroke may include:

• Sudden weakness
• Paralysis (an inability to move) or numbness of the face, arms, or legs, especially on one side of the body
• Confusion
• Trouble speaking or understanding speech
• Trouble seeing in one or both eyes
• Problems breathing
• Dizziness, trouble walking, loss of balance or coordination, and unexplained falls
• Loss of consciousness
• Sudden and severe headache

A transient ischemic attack (TIA) has the same signs and symptoms as a stroke. However, TIA symptoms usually last less than 1–2 hours (although they may last up to 24 hours). A TIA may occur only once in a person’s lifetime or more often.

At first, it may not be possible to tell whether someone is having a TIA or stroke. All stroke-like symptoms require medical care.

If you think you or someone else is having a TIA or stroke, call 9–1–1 right away. Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room. During a stroke, every minute counts.

Stroke Complications

After you’ve had a stroke, you may develop other complications, such as:

• Blood clots and muscle weakness. Being immobile (unable to move around) for a long time can raise your risk of developing blood clots in the deep veins of the legs. Being immobile also can lead to muscle weakness and decreased muscle flexibility.
• Problems swallowing and pneumonia. If a stroke affects the muscles used for swallowing, you may have a hard time eating or drinking. You also may be at risk of inhaling food or drink into your lungs. If this happens, you may develop pneumonia.
• Loss of bladder control. Some strokes affect the muscles used to urinate. You may need a urinary catheter (a tube placed into the bladder) until you can urinate on your own. Use of these catheters can lead to urinary tract infections. Loss of bowel control or constipation also may occur after a stroke.

Your doctor will diagnose a stroke based on your signs and symptoms, your medical history, a physical exam, and test results.

Your doctor will want to find out the type of stroke you’ve had, its cause, the part of the brain that's affected, and whether you have bleeding in the brain.

If your doctor thinks you’ve had a transient ischemic attack (TIA), he or she will look for its cause to help prevent a future stroke.

Medical History and Physical Exam

Your doctor will ask you or a family member about your risk factors for stroke. Examples of risk factors include high blood pressure, smoking, heart disease, and a personal or family history of stroke. Your doctor also will ask about your signs and symptoms and when they began.

During the physical exam, your doctor will check your mental alertness and your coordination and balance. He or she will check for numbness or weakness in your face, arms, and legs; confusion; and trouble speaking and seeing clearly.

Your doctor will look for signs of carotid artery disease, a common cause of ischemic stroke. He or she will listen to your carotid arteries with a stethoscope. A whooshing sound called a bruit (broo-E) may suggest changed or reduced blood flow due to plaque buildup in the carotid arteries.

Diagnostic Tests and Procedures

Your doctor may recommend one or more of the following tests to diagnose a stroke or TIA.

Brain Computed Tomography

A brain computed tomography (to-MOG-rah-fee) scan, or brain CT scan, is a painless test that uses x rays to take clear, detailed pictures of your brain. This test often is done right after a stroke is suspected.

A brain CT scan can show bleeding in the brain or damage to the brain cells from a stroke. The test also can show other brain conditions that may be causing your symptoms.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) uses magnets and radio waves to create pictures of the organs and structures in your body. This test can detect changes in brain tissue and damage to brain cells from a stroke.

An MRI may be used instead of, or in addition to, a CT scan to diagnose a stroke.

Computed Tomography Arteriogram and Magnetic Resonance Arteriogram

A CT arteriogram (CTA) and magnetic resonance arteriogram (MRA) can show the large blood vessels in the brain. These tests may give your doctor more information about the site of a blood clot and the flow of blood through your brain.

Carotid Ultrasound

Carotid ultrasound is a painless and harmless test that uses sound waves to create pictures of the insides of your carotid arteries. These arteries supply oxygen-rich blood to your brain.

Carotid ultrasound shows whether plaque has narrowed or blocked your carotid arteries.

Your carotid ultrasound test may include a Doppler ultrasound. Doppler ultrasound is a special test that shows the speed and direction of blood moving through your blood vessels.

Carotid Angiography

Carotid angiography (an-jee-OG-ra-fee) is a test that uses dye and special x rays to show the insides of your carotid arteries.

For this test, a small tube called a catheter is put into an artery, usually in the groin (upper thigh). The tube is then moved up into one of your carotid arteries.

Your doctor will inject a substance (called contrast dye) into the carotid artery. The dye helps make the artery visible on x-ray pictures.

Heart Tests

EKG (Electrocardiogram)

An EKG is a simple, painless test that records the heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.

An EKG can help detect heart problems that may have led to a stroke. For example, the test can help diagnose atrial fibrillation or a previous heart attack.

Echocardiography

Echocardiography (EK-o-kar-de-OG-ra-fee), or echo, is a painless test that uses sound waves to create pictures of your heart.

The test gives information about the size and shape of your heart and how well your heart's chambers and valves are working.

Echo can detect possible blood clots inside the heart and problems with the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to all parts of your body.

Blood Tests

Your doctor also may use blood tests to help diagnose a stroke.

A blood glucose test measures the amount of glucose (sugar) in your blood. Low blood glucose levels may cause symptoms similar to those of a stroke.

A platelet count measures the number of platelets in your blood. Blood platelets are cell fragments that help your blood clot. Abnormal platelet levels may be a sign of a bleeding disorder (not enough clotting) or a thrombotic disorder (too much clotting).

Your doctor also may recommend blood tests to measure how long it takes for your blood to clot. Two tests that may be used are called PT and PTT tests. These tests show whether your blood is clotting normally.

Treatment for a stroke depends on whether it is ischemic or hemorrhagic. Treatment for a transient ischemic attack (TIA) depends on its cause, how much time has passed since symptoms began, and whether you have other medical conditions.

Strokes and TIAs are medical emergencies. If you have stroke symptoms, call 9–1–1 right away. Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin lifesaving treatment on the way to the emergency room. During a stroke, every minute counts.

Once you receive immediate treatment, your doctor will try to treat your stroke risk factors and prevent complications by recommending heart-healthy lifestyle changes.

Treating an Ischemic Stroke or Transient Ischemic Attack

An ischemic stroke or TIA occurs if an artery that supplies oxygen-rich blood to the brain becomes blocked. Often, blood clots cause the blockages that lead to ischemic strokes and TIAs. Treatment for an ischemic stroke or TIA may include medicines and medical procedures.

Medicines

If you have a stroke caused by a blood clot, you may be given a clot-dissolving, or clot-busting, medication called tissue plasminogen activator (tPA). A doctor will inject tPA into a vein in your arm. This type of medication must be given within 4 hours of symptom onset. Ideally, it should be given as soon as possible. The sooner treatment begins, the better your chances of recovery. Thus, it’s important to know the signs and symptoms of a stroke and to call 9–1–1 right away for emergency care.

If you can’t have tPA for medical reasons, your doctor may give you antiplatelet medicine that helps stop platelets from clumping together to form blood clots or anticoagulant medicine (blood thinner) that keeps existing blood clots from getting larger. Two common medicines are aspirin and clopidogrel.

Medical Procedures

If you have carotid artery disease, your doctor may recommend a carotid endarterectomy or carotid artery angioplasty. Both procedures open blocked carotid arteries.

Researchers are testing other treatments for ischemic stroke, such as intra-arterial thrombolysis and mechanical clot removal in cerebral ischemia (MERCI).

In intra-arterial thrombolysis, a long flexible tube called a catheter is put into your groin (upper thigh) and threaded to the tiny arteries of the brain. Your doctor can deliver medicine through this catheter to break up a blood clot in the brain.

MERCI is a device that can remove blood clots from an artery. During the procedure, a catheter is threaded through a carotid artery to the affected artery in the brain. The device is then used to pull the blood clot out through the catheter.

Treating a Hemorrhagic Stroke

A hemorrhagic stroke occurs if an artery in the brain leaks blood or ruptures. The first steps in treating a hemorrhagic stroke are to find the cause of bleeding in the brain and then control it. Unlike ischemic strokes, hemorrhagic strokes aren’t treated with antiplatelet medicines and blood thinners because these medicines can make bleeding worse.

If you’re taking antiplatelet medicines or blood thinners and have a hemorrhagic stroke, you’ll be taken off the medicine. If high blood pressure is the cause of bleeding in the brain, your doctor may prescribe medicines to lower your blood pressure. This can help prevent further bleeding.

Surgery also may be needed to treat a hemorrhagic stroke. The types of surgery used include aneurysm clipping, coil embolization, and arteriovenous malformation (AVM) repair.

Aneurysm Clipping and Coil Embolization

If an aneurysm (a balloon-like bulge in an artery) is the cause of a stroke, your doctor may recommend aneurysm clipping or coil embolization.

Aneurysm clipping is done to block off the aneurysm from the blood vessels in the brain. This surgery helps prevent further leaking of blood from the aneurysm. It also can help prevent the aneurysm from bursting again. During the procedure, a surgeon will make an incision (cut) in the brain and place a tiny clamp at the base of the aneurysm. You’ll be given medicine to make you sleep during the surgery. After the surgery, you’ll need to stay in the hospital’s intensive care unit for a few days.

Coil embolization is a less complex procedure for treating an aneurysm. The surgeon will insert a tube called a catheter into an artery in the groin. He or she will thread the tube to the site of the aneurysm. Then, a tiny coil will be pushed through the tube and into the aneurysm. The coil will cause a blood clot to form, which will block blood flow through the aneurysm and prevent it from bursting again. Coil embolization is done in a hospital. You’ll be given medicine to make you sleep during the surgery.

Arteriovenous Malformation Repair

If an AVM is the cause of a stroke, your doctor may recommend an AVM repair. (An AVM is a tangle of faulty arteries and veins that can rupture within the brain.) AVM repair helps prevent further bleeding in the brain.

Doctors use several methods to repair AVMs. These methods include:

• Injecting a substance into the blood vessels of the AVM to block blood flow
• Surgery to remove the AVM
• Using radiation to shrink the blood vessels of the AVM

Treating Stroke Risk Factors

After initial treatment for a stroke or TIA, your doctor will treat your risk factors. He or she may recommend heart-healthy lifestyle changes to help control your risk factors.

Heart-healthy lifestyle changes may include:

• Heart-healthy eating
• Aiming for a healthy weight
• Managing stress
• Physical activity
• Quitting smoking

If heart-healthy lifestyle changes aren’t enough, you may need medicine to control your risk factors.

The time it takes to recover from a stroke varies—it can take weeks, months, or even years. Some people recover fully, while others have long-term or lifelong disabilities.

Ongoing care, rehabilitation, and emotional support can help you recover and may even help prevent another stroke.

If you’ve had a stroke, you’re at risk of having another one. Know the warning signs and what to do if a stroke or transient ischemic attack (TIA) occurs. Call 9–1–1 as soon as symptoms start.

Do not drive to the hospital or let someone else drive you. By calling an ambulance, medical personnel can begin lifesaving treatment on the way to the emergency room. During a stroke, every minute counts.