Ischemic Stroke: Symptoms, Causes, and Treatment

Medically Reviewed By Heidi Moawad, M.D.
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Ischemic stroke is when blood flow to a region of the brain is blocked. A common cause is a blood clot. Symptoms, which are typically sudden, can include arm or leg weakness, vision problems, confusion, and difficulty speaking or understanding speech. According to the American Stroke Association (ASA), approximately 87% of all strokes are ischemic strokes. This makes it the most common type of stroke. Recognizing the signs of ischemic stroke and receiving prompt medical attention is crucial to minimizing the damage it can cause.

This article will explain ischemic stroke symptoms and signs, the causes and risk factors, and treatment. Additionally, it will discuss the diagnosis, recovery, and outlook, and answer common questions about ischemic stroke.

What is an ischemic stroke?

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An ischemic stroke is a lack of blood supply to a region of the brain, usually due to a blood clot. Also called an embolic stroke or thrombotic stroke, there are two types of ischemic stroke.

Cerebral thrombosis: A cerebral thrombosis occurs when a blood clot forms in an artery in the brain and blocks blood flow.

Cerebral embolism: A cerebral embolism occurs when a blood clot forms somewhere else in the body and moves into a blood vessel that supplies the brain.

The clot stops blood flow, depriving part of the brain of oxygen and nutrients. This is ischemia. As a result, brain cells start to die, leading to damage in the brain. This is a process called infarction.

Ischemic vs. hemorrhagic stroke

Hemorrhagic stroke is when an artery ruptures and starts to bleed into the brain. As the blood builds up, it starts to press on the surrounding brain tissue, which can damage it. According to the ASA, approximately 13% of stroke cases are hemorrhagic strokes.

Learn more about brain hemorrhage here.

What are the symptoms of an ischemic stroke?

The symptoms of ischemic stroke come on suddenly. They include:

  • weakness or numbness in the arm, leg, or face (especially on one side of the body)
  • confusion
  • trouble speaking or understanding speech
  • impaired vision in one or both eyes
  • dizziness, difficulty walking, or loss of coordination or balance
  • severe and unexplained headache

Early warning signs of ischemic stroke

It is possible to have a precursor to an ischemic stroke. This mini-stroke, a transient ischemic attack (TIA), usually lasts a few minutes. The symptoms may be the same as with an ischemic stroke but for a shorter duration.

Learn more about TIAs here.

When to contact a doctor or dial 911

To help you identify and respond to someone who could be having a stroke or TIA, remember the acronym FAST:

  • Face: Have the person smile and see if one side of the face droops.
  • Arms: Have the person raise both arms and see if one arm drifts downward.
  • Speech: Have the person repeat a simple phrase, such as, “I like to walk the dog.” Observe if the speech is slurred or hard to understand.
  • Time: If the person exhibits any of these symptoms, immediately call 911.

What causes an ischemic stroke?

Ischemic stroke can occur when a blood clot or narrowing of the arteries blocks blood flow to a part of the brain.

Plaque is a fatty substance that can collect inside arteries. Over time, it causes atherosclerosis and narrows the arteries. The narrowing, or stenosis, reduces blood flow through the arteries.

Blood clots can form where plaque breaks open. As the clot grows, it can block blood flow to that part of the brain.

Blood clots can also come from another area of the body and travel to the brain. They get stuck in a smaller blood vessel and block blood flow to that part of the brain. This process can occur with pieces of plaque too.

Risk factors

Risk factors for ischemic stroke include:

Other risk factors for stroke include:

  • being of older age
  • being of African American, Alaska Native, American Indian, and Hispanic American ethnicity
  • having a family history of stroke
  • having high stress levels or related conditions
  • being exposed to air pollution
  • getting insufficient exercise or sleep
  • using cocaine and other illegal drugs
  • being overweight or having obesity
  • having a stroke previously, especially if the risk factors persist

How do you diagnose an ischemic stroke?

Diagnosing ischemic stroke usually involves several diagnostic tests, such as:

  • Imaging tests: CT scans and MRI are types of imaging tests that can create detailed pictures of the brain. The physician will inject a contrast dye that makes the blood vessels stand out. They may also scan the carotid arteries in your neck and those in the upper chest.
  • Blood tests: The physician may treat you with a drug that dissolves clots. Beforehand, they will order blood tests to evaluate your blood for clotting. They may order other tests as well.
  • EEG: An EEG measures electrical activity in the brain.
  • ECG: An ECG measures electrical activity in the heart.
  • Echocardiogram: Also known as an “echo,” this imaging test is an ultrasound of the heart as it is beating. It can identify heart problems.
  • Lumbar puncture: This spinal fluid test can detect signs of damaged blood cells, which is a possible clue to the type of stroke.

The physician will also perform a physical exam and ask you or a person with you about your full medical history and medications you may take.

Learn more about heart disease and stroke here.

How do you treat an ischemic stroke?

Treating an ischemic stroke as soon as possible is necessary to reduce the chance of permanent or widespread brain damage. Treatment focuses on breaking up or removing the blood clot to restore blood flow. These treatments include:

  • Alteplase: This drug is a synthetic version of the enzyme tissue plasminogen activator. Commonly known as a “clot-busting drug,” the doctor must administer alteplase by IV within 3–4.5 hours of the onset of symptoms.
  • Thrombectomy: This procedure removes the clot using angioplasty, stenting, or a stent retriever to clear the blocked artery.
  • Other medications: Aspirin, clopidogrel, and anticoagulants help prevent stroke.

While in the hospital, the care team delivers supportive care and lifesaving treatment. Examples include breathing support, IV fluids, and compression therapy to reduce the chance of deep vein thrombosis.

How do you recover from an ischemic stroke?

Ischemic stroke may impair speech, body movements, eating, and bladder, among other functions. The doctor will develop a treatment and recovery plan. They may prescribe speech, physical, and occupational therapy to address those problems.

Read about stroke recovery here.

What is the survival rate and outlook?

The outlook varies greatly between people. It depends on:

  • the severity of the stroke
  • the affected area of the brain
  • how quickly the stroke received diagnosis and treatment
  • the type of rehabilitation
  • how effective treatment is

Read more about stroke survival here.

Can you prevent an ischemic stroke?

The doctor may prescribe blood thinners to help prevent a first or second ischemic stroke. Alternatively, they may perform a carotid endarterectomy to remove plaque.

Learn about carotid artery surgery here.


Blood thinners could help stop blood clots from forming and reduce the chance of stroke. This class of medication includes aspirin, clopidogrel, and anticoagulants.

Lifestyle changes

Maintaining a healthy lifestyle goes a long way in keeping ischemic stroke at bay. A healthy lifestyle includes:

  • eating a healthy, balanced diet
  • exercising regularly
  • not smoking
  • reducing stress
  • prioritizing sleep
  • maintaining a moderate weight

Other frequently asked questions

Below are some other questions that people ask about ischemic stroke.

How serious is an ischemic stroke?

An ischemic stroke can be very serious. It can cause permanent brain damage and reduce mobility. Some ischemic strokes can be fatal.

What is the difference between stroke and ischemic stroke?

A stroke occurs when bleeding or a blood clot reduces or stops blood flow to an area of the brain. An ischemic stroke is when a blood clot blocks blood flow in a vessel in the brain.

Can you feel a stroke coming on?

Stroke symptoms, such as vision loss and slurred speech, are usually very noticeable. Sometimes stroke symptoms can develop gradually over minutes. Other strokes occur after a TIA or mini-stroke.

Most of the time, strokes occur suddenly. That is why it is crucial to get medical attention as soon as stroke symptoms begin.


Ischemic stroke occurs when a blood clot blocks a vessel in the brain, stopping blood flow to that part of the brain. Treatment within 3 hours of symptom onset can help minimize brain damage. This treatment includes medication and sometimes medical procedures to break up the blood clot.

Recovery from an ischemic stroke depends on the severity of the stroke, the time from symptom onset to treatment, and other factors. If you have risk factors for ischemic stroke, discuss them with your healthcare professional. They can help manage these risk factors and reduce your chance of stroke.

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Medical Reviewer: Heidi Moawad, M.D.
Last Review Date: 2022 Jul 1
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