What is ischemic stroke?
Ischemic stroke is one of three types of stroke. It’s also referred to as brain ischemia and cerebral ischemia.
This type of stroke is caused by a blockage in an artery that supplies blood to the brain. The blockage reduces the blood flow and oxygen to the brain, leading to damage or death of brain cells. If circulation isn’t restored quickly, brain damage can be permanent.
Approximately 87 percent of all strokes are ischemic stroke.
The third type of stroke is transient ischemic attack (TIA), also known as a ministroke. This type of stroke is caused by a temporary blockage or decreased blood flow to the brain. Symptoms usually disappear on their own.
Specific symptoms of an ischemic stroke depend on what region of the brain is affected. Certain symptoms are common across most ischemic stroke, including:
- vision problems, such as blindness in one eye or double vision
- weakness or paralysis in your limbs, which may be on one or both sides, depending on the affected artery
- dizziness and vertigo
- loss of coordination
- drooping of face on one side
Once symptoms start, it’s crucial to get treatment as quickly as possible. This makes it less likely that damage becomes permanent. If you think someone is having a stroke, evaluate them using FAST:
- Face. Is one side of their face drooping and hard to move?
- Arms. If they raise their arms, does one arm drift downward, or do they have significant difficulty raising their arm?
- Speech. Is their speech slurred or otherwise strange?
- Time. If the answer to any of these questions is yes, it’s time to call your local emergency services.
Even though TIA lasts for a brief period and usually resolves on its own, it also requires a doctor. This can be a warning sign of a full-blown ischemic stroke.
Clots usually start in the heart and travel through the circulatory system. A clot can break up on its own or become lodged in an artery. When it blocks a brain artery, the brain doesn’t get enough blood or oxygen, and cells start to die.
Ischemic stroke caused by a fatty buildup happens when plaque breaks off from an artery and travels to the brain. Plaque can also build up in the arteries that supply blood to the brain and narrow those arteries enough to cause ischemic stroke.
Global ischemia, which is a more severe type of ischemic stroke, happens when the flow of oxygen to the brain is greatly reduced or completely stopped. This is usually caused by a heart attack, but it can also be caused by other conditions or events, such as carbon monoxide poisoning.
Circulatory conditions are the main risk factor for ischemic stroke. That’s because they increase your risk for clots or fatty deposits. These conditions include:
- high blood pressure
- high cholesterol
- atrial fibrillation
- prior heart attack
- sickle cell anemia
- clotting disorders
- congenital heart defects
Other risk factors include:
- being overweight, especially if you have a lot of abdominal fat
- heavy alcohol misuse
- use of certain drugs, such as cocaine or methamphetamines
Ischemic stroke is also more common in people who have a family history of stroke or who’ve had past strokes. Men are more likely than women to have ischemic stroke, while blacks have a higher risk than other races or ethnic groups. Risk also increases with age.
A doctor can usually use a physical exam and family history to diagnose ischemic stroke. Based on your symptoms, they can also get an idea of where the blockage is located.
If you have symptoms such as confusion and slurred speech, your doctor might perform a blood sugar test. That’s because confusion and slurred speech are also symptoms of severe low blood sugar. Learn more about the effects of low blood sugar on the body.
Once your doctor has diagnosed ischemic stroke, they’ll try to figure out when it started and what the root cause is. An MRI is the best way determine when the ischemic stroke started. Tests used to determine a root cause might include:
- an electrocardiogram (ECG or EKG) to test for abnormal heart rhythms
- echocardiography to check your heart for clots or abnormalities
- an angiography to see which arteries are blocked and how severe the blockage is
- blood tests for cholesterol and clotting problems
If ischemic stroke isn’t treated promptly, it can lead to brain damage or death.
The main treatment for ischemic stroke is intravenous tissue plasminogen activator (tPA), which breaks up clots. 2018 guidelines from the American Heart Association (AHA) and the American Stroke Association (ASA) state that tPA is most effective when it’s given within four and a half hours from the start of a stroke. It can’t be given more than five hours after the start of the stroke. Because tPA can result in bleeding, you can’t take it if you have a history of:
- hemorrhagic stroke
- bleeding in the brain
- recent major surgery or head injury
It also can’t be used by anyone taking anticoagulants.
If tPA doesn’t work, clots can be removed through surgery. A mechanical clot removal can be performed up to 24 hours after the onset of stroke symptoms.
Long-term treatments include aspirin (Bayer) or an anticoagulant to prevent further clots.
If ischemic stroke is caused by a condition such as high blood pressure or atherosclerosis, you’ll need to receive treatment for those conditions. For example, your doctor may recommend a stent to open an artery narrowed by plaque or statins to lower blood pressure.
After ischemic stroke, you’ll have to stay in the hospital for observation for at least a few days. If the stroke caused paralysis or severe weakness, you may also need rehabilitation afterward to regain function.
Rehabilitation is often necessary to regain motor skills and coordination. Occupational, physical, and speech therapy might also be useful to help regain other lost function. Younger people and people who start improving quickly are likely to recover more function.
If any issues are still present after a year, they’ll likely be permanent.
Having one ischemic stroke puts you at a higher risk for having another. Taking steps to reduce your risk, such as quitting smoking, are an important part of long-term recovery. Learn more about stroke recovery.
Ischemic stroke is a serious condition and requires prompt treatment. However, with the correct treatment, most people with ischemic stroke can recover or maintain enough function to take care of their basic needs. Knowing the signs of ischemic stroke can help save your life or the life of someone else.