What Is a Stroke? Symptoms, Causes, Diagnosis, Treatment, and Prevention

A stroke occurs when the flow of blood to the brain is blocked. It is a medical emergency, because blood carries oxygen, and brain cells begin to die within a few minutes without it.

Strokes can occur at any age, but stroke risk increases as you get older.

While not every stroke can be prevented, there are many steps you can take to reduce your risk.

It’s important to recognize the signs of a stroke, and to call 911 for emergency medical attention if you think someone is having one. Getting treatment quickly may prevent death or disability. (1)

Signs and Symptoms of a Stroke

Knowing the signs and symptoms of a stroke can help save lives.

The type and severity of stroke symptoms depend on the area of the brain that is affected.

Signs and symptoms of a stroke can vary between men and women and may include:

  • Sudden numbness, weakness, or inability to move the face, arm, or leg (especially on one side of the body)
  • Confusion
  • Trouble speaking or understanding speech
  • Trouble seeing in one or both eyes
  • Dizziness, trouble walking, or loss of balance or coordination
  • Sudden, severe headache

The acronym FAST can help you remember the signs and symptoms of stroke.

  1. Face drooping Ask the person to smile. Is the smile uneven?
  2. Arm weakness Ask the person to raise both arms. Does one drift downward?
  3. Speech difficulty Is speech slurred or hard to understand? Ask the person to repeat a simple sentence like: "The sky is blue." Is the sentence repeated correctly?
  4. Time to call 911 If someone shows any of these symptoms, even if the symptoms go away, call 911. Check the time so you can tell responders when the symptoms first started.

People who experience a stroke have the best chance of survival, and may have less disability, if someone around them recognizes the signs and acts quickly by calling 911. (2)

Learn More About Stroke Symptoms

Causes and Risk Factors of Stroke

There are two main types of stroke, with different causes:

  • Ischemic strokes are caused by blood clots.
  • Hemorrhagic strokes are caused by bleeding in or around the brain.

Ischemic strokes account for about 87 percent of all strokes. They happen when there's a blood clot that blocks blood flow to a part of the brain. There are two ways this can happen:

  1. A clot can form in a blood vessel of the neck or brain that has been narrowed by a buildup of plaque. Plaque is a combination of fat, cholesterol, and other substances that accumulate in the inner lining of the artery walls. Plaque buildup is known as atherosclerosis, or "hardening of the arteries."
  2. A clot can arise from the heart or break off from a blood vessel elsewhere in the body and travel to the brain where it becomes stuck in one of the brain's tiny blood vessels. This is called embolism. (3)

A hemorrhagic stroke occurs when a weakened blood vessel in the brain ruptures and bleeds into surrounding brain tissue. This puts too much pressure on blood cells in the surrounding tissue, cutting off their blood supply and causing damage.

An aneurysm — a weak spot in a blood vessel wall that balloons outward — can lead to a hemorrhagic stroke, as can a tangle of malformed blood vessels called an arteriovenous malformation.

About 13 percent of all strokes are hemorrhagic strokes. (4)

A number of factors may increase your risk of having a stroke. General stroke risk factors include the following:

  • Older age (especially 55 or older)
  • Being a Black American
  • Being a man
  • Lack of physical activity
  • Heavy alcohol consumption
  • Smoking or exposure to secondhand smoke
  • Use of recreational stimulants drugs (such as cocaine or amphetamines)
  • Being overweight or obese
  • High blood pressure
  • High cholesterol
  • Diabetes
  • Sleep apnea
  • Cardiovascular disease
  • COVID-19
  • Personal or family history of stroke or heart attack

There are also specific risk factors for a hemorrhagic stroke:

  • Uncontrolled high blood pressure
  • Excessive use of anticoagulant drugs (blood thinners)
  • Trauma (such as an accident or fall)
  • Cerebral amyloid angiopathy (protein deposits in blood vessel walls)
  • Ischemic stroke (having had one can lead to hemorrhagic stroke) (5)

How Is a Stroke Diagnosed?

Your emergency medical team will diagnose a stroke on the basis of several factors, including your symptoms, medical history, a physical exam, and diagnostic tests.

The following brain and heart tests may be used to help diagnose a stroke.

  • Computed tomography (CT) scan A brain CT scan uses X-rays to create images of your brain.
  • Magnetic resonance imaging (MRI) A brain MRI uses magnets and radio waves to create images of your brain.
  • Carotid ultrasound or carotid angiography These show the insides of the arteries that supply blood to the brain.
  • Echocardiogram This test uses sound waves to create images of your heart, and may detect the source of blood clots that have traveled from your heart to your brain.

A brain CT scan or MRI may be used to identify whether your stroke is ischemic (caused by clotting) or hemorrhagic (caused by bleeding), which is essential to treating your stroke.

Blood tests may also be helpful to identify a stroke, such as by checking how quickly your blood clots. (5)

Prognosis of Stroke

Stroke can lead to outcomes ranging from a full recovery (without any lasting disability) to death.

After emergency treatment and monitoring, your stroke care will be focused on helping you recover as much function as possible.

If you experience ongoing disability because of your stroke, the functions that are affected may depend on the side of your brain where your stroke occurred.

A stroke on the right side of your brain tends to affect movement and sensation on the left side of your body. A stroke on the left side of your brain tends to affect the right side of your body, and may also affect speech and language.

Most people who have a stroke will enter a rehabilitation program, which may begin before you leave the hospital. Your program will take into account your overall health, degree of disability from stroke, recovery and lifestyle priorities, and support system. (5)

Learn More About How Strokes Are Diagnosed

Duration of a Stroke

When you have a stroke, brain cells in the affected area begin to die within minutes of losing oxygen.

Many treatment options are most effective when given as soon as possible after a stroke begins. That’s why it’s important to seek emergency medical attention immediately, and to note when a person’s stroke symptoms began. (5)

There is no standard duration for a stroke. Without treatment, blood flow to your brain may be blocked for a variable period of time, perhaps indefinitely. (6)

Treatment and Medication Options for Stroke

Treatments for stroke depend on the type of stroke.

The main treatment for an ischemic stroke is alteplase, or tPA, a thrombolytic medication or "clot buster." It can quickly break up or dissolve blood clots that are blocking blood flow to the brain. This drug must be started within a few hours after stroke symptoms first appear.

For an ischemic stroke, doctors may also perform an endovascular catheter-based procedure, in which a long, narrow tube is pushed through a blood vessel into your brain to remove a large blood clot.

Treatments for a hemorrhagic stroke include controlling blood pressure and stopping any medications that could increase bleeding, including warfarin and aspirin. You may also receive a blood transfusion with blood clotting factors to stop ongoing bleeding.

In addition, a hemorrhagic stroke may require an endovascular procedure (accessed through a blood vessel) or surgery to help stop and prevent further bleeding. (7)

Learn More About How Strokes Are Treated

Prevention of Stroke

Management of lifestyle-based risk factors may help prevent a stroke. In addition, if you are at high risk for an ischemic stroke, you may be prescribed certain medications to reduce your risk.

Lifestyle-based stroke prevention measures include the following:

  • Eating lots of fruits and vegetables
  • Reducing saturated fat in your diet
  • Not using tobacco or smoking
  • Drinking alcohol in moderation (or not at all)
  • Not using recreational stimulant drugs
  • Maintaining a healthy weight
  • Getting enough exercise
  • Controlling blood pressure
  • Managing diabetes
  • Treating sleep apnea

If you have already had a transient ischemic attack (TIA), also known as a mini-stroke, or ischemic stroke, your doctor may recommend certain drugs to reduce your stroke risk, such as:

Antiplatelet drugs These medications make your blood less “sticky” and include aspirin, dipyridamole, and Plavix (clopidogrel).

Anticoagulants These medications reduce blood clotting and include heparin and warfarin, along with newer drugs like Pradaxa (dabigatran), Xarelto (rivaroxaban), Eliquis (apixaban) and Savaysa (edoxaban). (5)

Learn More About Preventing Strokes

Complications of Stroke

A stroke may cause temporary or permanent disabilities.

Stroke complications will depend on what part of the brain was affected by the stroke, and how long that area of the brain was deprived of oxygen.

Common stroke complications include:

  • Paralysis or loss of muscle movement
  • Memory loss or cognitive difficulty
  • Trouble with talking or swallowing
  • Pain or numbness
  • Emotional difficulty or loss of motivation (5)

Over time, most people who have a stroke will recover some of the function they have lost.

Stroke rehabilitation programs can help, although these programs will not "cure" or reverse brain damage caused by a stroke. Instead, the goal of stroke rehabilitation is to help stroke survivors live as independently as possible while adjusting to new limitations.

Stroke survivors may require:

  • Speech therapy
  • Physical therapy and strength training
  • Occupational therapy (relearning skills required for daily living)
  • Psychological counseling or therapy
  • Social work or case management

Some common types of stroke programs and facilities include:

  • Inpatient rehabilitation or nursing facilities that provide 24-hour care
  • Outpatient facilities, where you may spend several hours a day doing rehabilitation activities
  • Home-based programs, in which therapists come to you (8,5)

Aphasia After Stroke

Aphasia is a condition characterized by the sudden loss of the ability to communicate and is a common complication of a stroke. Approximately 1 million people in the United States have aphasia, and there are nearly 180,000 new cases each year, according to the National Aphasia Association.

There are several types of aphasia. Symptoms may include:

  • Speaking in short or incomplete sentences
  • Speaking in ways that do not make any sense or saying unrecognizable words
  • Substituting one word or sound for another
  • Not understanding what other people are saying
  • Writing words or sentences that do not make any sense (9)

Learn More About Aphasia

Insomnia After Stroke

Sleep is important for general health and well-being, as well as for learning. For stroke survivors trying to relearn basic skills, adequate rest is even more important — it’s a key part of the stroke recovery process.

But good sleep can often be elusive for people who’ve had a stroke. A study published in May 2018 found evidence that insomnia may be a long-term side effect for stroke survivors, indicating that treating insomnia may be an important part of post-stroke rehabilitation.

This research shows the importance of including treatment of sleep disorders such as insomnia in stroke rehabilitation practices — something that doctors generally do not do, experts say. (10)

Learn More About the Link Between Insomnia and Stroke

Neuropathy After Stroke

A stroke can damage your brain, potentially causing a type of neuropathy called central neuropathy. In this form of neuropathy, you may experience burning, stabbing, or pins-and-needles sensations in the same areas of your body that are affected by your stroke in other ways, according to Flint Rehab — including your face, arm, leg, torso, or even half of your body. This form of post-stroke pain tends to be ongoing, and typically develops soon after a stroke but can also start later on. About 10 percent of stroke survivors experience central pain or neuropathy, according to Stanford Medicine.

Research and Statistics: How Common Are Strokes?

Every year, more than 795,000 people in the United States have a stroke. About 610,000 of these are first-time strokes, according to the Centers for Disease Control and Prevention (CDC).

In the United States, someone has a stroke every 40 seconds, and someone dies of a stroke every four minutes, on average. Stroke is the fifth leading overall cause of death.

More than half of all stroke survivors age 65 and older will have long-term mobility impairment.

While older people are at higher risk for stroke, about a third of people hospitalized for stroke are younger than 65. (11)

BIPOC and Stroke

A number of studies have looked at differences in stroke risk among specific racial and ethnic populations, including Black, Indigenous, and People of Color (BIPOC) communities.

Black Americans are about twice as likely to have a first stroke as white Americans. Black people also have the highest rate of death due to stroke in the United States.

While the death rate from stroke has been dropping for decades in all racial and ethnic groups, for reasons that aren’t clear, Hispanic Americans have seen an increase in this death rate since 2013. (11)

In one study, researchers found that in a group of more than 3,000 older people in New York City, the risk of stroke was highest in Black participants, at 13 per 1,000 person-years (a way to measure incidence rates that shows how often something will happen if, for example, 100 people were followed for 10 years). This was followed by Hispanic participants, at 10; and white participants, at 9. When researchers looked just at those over age 85, Hispanic people had the highest incidence of stroke.

When the researchers controlled for demographic factors that may affect stroke risk, the gap was even greater between white and Black participants, with Black people experiencing a 51 percent higher risk. (12)

Hospital readmission rates after a stroke appear to be similar for different racial and ethnic groups. Among nearly 17,000 stroke patients in Florida, the 30-day readmission rate was 17.2 percent for Black patients, 16.7 percent for Hispanic patients, and 14.4 percent for white patients. (13)

Conditions Related to Stroke

transient ischemic attack (TIA), the event known as a mini-stroke, can be the result of a temporary blockage caused by a blood clot in the brain. It lasts for a few minutes and doesn’t cause any permanent damage.

A TIA can be a warning sign of a future stroke. As many as 10 to 15 percent of people who experience a TIA will have a major stroke within the next three months, according to the CDC.

Like a major stroke, a TIA is a medical emergency. It’s not possible to know if you’re having a TIA or a major stroke.

More than a third of people who have a TIA will have a major stroke within a year if they don’t receive treatment. (14)

Ischemic strokes are caused by blood clots that form in or travel to the blood vessels that supply your brain with oxygen and nutrients. Clots can also block blood flow to other areas of your body, causing the following conditions:

Resources We Love

Favorite Stroke Organizations

World Stroke Organization (WSO)

The WSO is the world’s leading organization aimed at reducing the burden of stroke through prevention, treatment, and care. Their website includes a global stroke fact sheet, as well as resources to help people interested in stroke advocacy.

American Stroke Association (ASA)

The ASA is a division of the American Heart Association (AHA). On their website, you can find information on all aspects of stroke and its treatment. There are also sections on caregiver support and ways to get involved in advocacy.

Brain & Life

Brain & Life is the patient site of the American Academy of Neurology. The website features articles and online-only content from Brain & Life magazine, including stories on stroke prevention, treatment, and recovery.

Favorite Stroke Bloggers

Flint Rehab Neurological Recovery Blog

This blog by a Michigan-based stroke rehab facility offers tips and tools for rebuilding your life after a stroke. Topics of posts include treatment options for aphasia, what you need to know about driving after a stroke, and dealing with the emotional side of stroke aftermath. The facility also has an online stroke support group on Facebook.

Favorite Stroke Recovery App

Cozi

Cozi is a family organizer that helps you keep track of multiple schedules, which is helpful if a stroke survivor has more than one caregiver. The app provides a shared color-coded calendar, and you can set reminders for important things like medical appointments or taking medications.

Favorite Support Groups

Support Network — American Heart Association

While online support groups can offer friendship and tips, in-person support groups can be helpful for making new local friends and for conversation, especially if a stroke has caused cognitive or speech loss. The American Heart Association offers a resource where you can find in-person support groups by zip code, as well as participate in online support groups and read stories from stroke survivors.

Favorite Stroke Wellness Retreat

Retreat & Refresh Stroke Camp

Throughout the year, across the country, Retreat & Refresh holds weekend retreats for stroke survivors and their families. Check their website to find a retreat in your area or learn about local events on stroke. (All events for 2020 are canceled due to the COVID-19 pandemic, and events will resume in 2021.)

Editorial Sources and Fact-Checking

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Resources

  1. Stroke. Centers for Disease Control and Prevention. April 7, 2020.
  2. Stroke Symptoms. American Stroke Association.
  3. Ischemic Stroke (Clots). American Stroke Association.
  4. Hemorrhagic Stroke (Bleeds). American Stroke Association.
  5. Stroke. Mayo Clinic. August 8, 2020.
  6. How Long Does a Stroke Last? UPMC Health Beat. July 24, 2017.
  7. Stroke Treatment. American Stroke Association.
  8. Recovering From Stroke. Centers for Disease Control and Prevention. January 31, 2020.
  9. Aphasia. Mayo Clinic. April 22, 2020.
  10. Sterr A, Kuhn M, Nissen C, et al. Post-Stroke Insomnia in Community-Dwelling Patients With Chronic Motor Stroke: Physiological Evidence and Implications for Stroke Care. Scientific Reports. May 30, 2018.
  11. Stroke Facts. Centers for Disease Control and Prevention. September 8, 2020.
  12. Gardener H, Sacco RL, et al. Race and Ethnic Disparities in Stroke Incidence in the Northern Manhattan Study. Stroke. February 12, 2020.
  13. Gardener H, Leifheit EC, et al. Race-Ethnic Disparities in 30-Day Readmission After Stroke Among Medicare Beneficiaries in the Florida Stroke Registry. Journal of Stroke & Cerebrovascular Diseases. October 11, 2019.
  14. Types of Stroke. Centers for Disease Control and Prevention. January 31, 2020.
  15. Peripheral Vascular Disease (PVD), Peripheral Artery Disease (PAD). ColumbiaDoctors.
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