Ischaemic Stroke

Ischaemic stroke is a life-threatening emergency that occurs when blood flow to part of the brain is blocked, most commonly by a blood clot. It is the most common type of stroke, accounting for about 87% of all cases. Every second counts—recognizing the warning signs and getting immediate treatment can be the difference between recovery and permanent disability or death.

What is an ischaemic stroke?
What causes ischaemic strokes?
Warning signs and symptoms
Risk factors
How is it diagnosed?
Treatment options
Prevention
Recovery and life after stroke

What is an ischaemic stroke?

An ischaemic stroke happens when something blocks a blood vessel in your brain, cutting off the supply of blood and oxygen to brain tissue^[1]. When brain cells cannot get the oxygen and nutrients they need from blood, they start to die within minutes^[6]. This can cause lasting brain damage, long-term disability, or even death.

Ischaemic stroke is the most common type of stroke. Around 85% to 87% of all strokes are ischaemic strokes^[3]^[5]. The other 15% are caused by bleeding in or around the brain, known as haemorrhagic stroke^[5].

If you think you or someone you’re with is having a stroke, immediately call emergency services. The sooner someone is diagnosed and treated, the more likely they’ll survive a stroke. Every second counts^[2].

What causes ischaemic strokes?

Ischaemic strokes are usually caused by a blood clot or a piece of fatty plaque (a sticky substance made up of cholesterol and fat) that blocks an artery in the brain^[7]. The main cause of ischaemic stroke is atherosclerosis, a disease in which fatty deposits build up inside blood vessel walls, making them narrow and hard^[3].

There are two main types of blockages that cause ischaemic strokes^[3]:

Cerebral thrombosis is a blood clot that develops directly at the site of fatty plaque within a blood vessel that supplies blood to the brain.
Cerebral embolism is a blood clot that forms in the heart or in large arteries of the upper chest or neck, or at another location in the body. Part of the blood clot breaks loose, enters the bloodstream and travels through the brain’s blood vessels until it reaches vessels too small to let it pass.

A main cause of embolism is an irregular heartbeat called atrial fibrillation. It can cause clots to form in the heart, which can then break loose and travel to the brain^[3].

Transient ischaemic attack

A transient ischaemic attack (TIA)—sometimes called a “mini-stroke”—is like a stroke, but the effects are temporary^[2]. The symptoms usually last only a few minutes or hours and then go away^[6]. However, a TIA is a serious warning sign. A person who has a TIA has a very high risk of having a true permanent stroke soon and needs emergency medical care as quickly as possible^[2].

Warning signs and symptoms

Strokes happen suddenly. The symptoms you experience will depend on which area of your brain is affected^[2]. Common symptoms of ischaemic stroke include^[1]^[2]^[7]:

Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
Sudden confusion
Sudden trouble speaking or understanding speech
Slurred or garbled speaking
Sudden trouble seeing in one or both eyes
Blurry vision or double vision
Sudden trouble walking
Dizziness or loss of balance or coordination
Sudden severe headache with no known cause
Drooping muscles on one side of the face
Memory loss
Confusion or agitation
Nausea and vomiting

How to recognize stroke: BE FAST

To recognize the warning signs in yourself or a loved one, remember the acronym BE FAST^[2]:

Balance: Watch for a sudden loss of balance.
Eyes: Look out for sudden vision loss or changes in one or both eyes.
Face: Smile. Look for a droop on one or both sides of your face.
Arms: Raise both arms. If you’re having a stroke, one arm will sag or drop in a way that it usually doesn’t.
Speech: You might slur your speech or have trouble choosing the right words.
Time: Time is critical—call for help immediately. If possible, note when symptoms start. Telling a healthcare provider when symptoms began can help them know which treatment options are best for you.

Risk factors

Anyone can have a stroke, but some things put you at higher risk^[1]. Risk factors you cannot change include^[1]^[7]:

Being 55 years old or older
Being male
Having a family history of strokes or heart attacks
Having had a previous stroke or heart attack

Many risk factors for stroke can be controlled or managed. Medical conditions that increase your risk include^[1]^[2]^[7]:

High blood pressure (the leading preventable risk factor for stroke)
High cholesterol
Diabetes
Atrial fibrillation (irregular heartbeat)
Heart disease or heart valve disease
Atherosclerosis (hardening of the arteries)
Obstructive sleep apnea
Blood clotting disorders

Lifestyle factors that raise your risk include^[1]^[9]:

Smoking
Being overweight or obese
Physical inactivity
Drinking alcohol heavily
Consuming a diet high in cholesterol, fat and salt

How is it diagnosed?

Prompt evaluation is essential to preserve brain tissue and reduce long-term disability^[4]. To make a diagnosis, your healthcare provider may do a physical exam, ask about your symptoms and medical history, and use imaging tests^[6].

Early diagnosis relies on clinical assessment and rapid imaging, typically a non-contrast computed tomography (CT) scan and, when available, diffusion-weighted magnetic resonance imaging (MRI)^[4]. These imaging tests help doctors see what’s happening inside your brain and determine whether the stroke is ischaemic or haemorrhagic, because the two types cannot be reliably differentiated based on clinical examination findings alone^[8].

Other imaging tests may be done to help find the cause of the stroke. These may include tests of the heart and blood vessels^[6]. Blood tests may also be performed^[10].

Treatment options

Ischaemic stroke is a medical emergency. The urgent goal of treatment is to remove or break up the blood clot and restore blood flow to the brain^[3]^[11]. Management priorities include stabilizing breathing and circulation, and identifying candidates for treatments to restore blood flow^[4].

Clot-busting medication (thrombolysis)

The main treatment for ischaemic stroke is a medicine called tissue plasminogen activator (tPA), also known as alteplase^[11]. This is a clot-busting medicine that breaks up blood clots in the brain^[14]. It helps to save more of the brain by allowing blood to return to brain cells more quickly, so fewer brain cells die and the impact of the stroke can be reduced^[14].

This medicine is usually given through a small tube into a vein in your arm^[14]. It must be given within 3 to 4.5 hours after stroke symptoms start^[11]^[14]. The sooner treatment begins, the better your chances of recovery^[11].

Not everyone can have thrombolysis. There are guidelines for who can and cannot have it, to make sure it’s safe and effective^[14]. Reasons why thrombolysis may not be given include arriving at hospital outside the time window for treatment, having a very mild or very severe stroke, or having certain other medical conditions^[14].

Mechanical clot removal (thrombectomy)

A thrombectomy is a procedure that physically removes the clot from the blood vessel^[11]. A surgeon puts a long, flexible tube called a catheter into your upper thigh and threads it to the blocked artery in the brain^[11]. Mechanical thrombectomy may be considered for large vessel blockages within 24 hours of symptom onset^[4].

Other medications

If you cannot have tPA, your provider may give you an anticoagulant or blood-thinning medicine, such as aspirin or clopidogrel^[11]. These help stop blood clots from forming or getting larger. The main side effect of these medicines is bleeding^[11].

After treatment, your provider may prescribe medicines to manage your blood pressure, cholesterol, or other health problems such as diabetes that may increase your risk for another stroke^[6].

Surgery

Some people may need surgery or a procedure to open up blocked arteries and restore blood flow to the brain. This can include removing plaque build-up from the carotid arteries, which supply blood to the brain^[6].

Prevention

Many strokes can be prevented through healthy lifestyle choices and working with your healthcare team to control health conditions that raise your risk for stroke^[20]. Up to 80% of strokes can be prevented^[21].

Control medical conditions

If you have heart disease, high cholesterol, high blood pressure, or diabetes, you can take steps to lower your risk for stroke^[20]. Controlling blood pressure through diet, regular exercise, reducing sodium and, if needed, medications is important to reducing your risk^[19]. Uncontrolled high blood pressure is the leading cause of stroke^[19].

Your doctor should check your cholesterol levels at least once every five years^[20]. High blood pressure usually has no symptoms, so be sure to have it checked on a regular basis^[20].

Make healthy lifestyle changes

The best way to prevent stroke is by making heart-healthy lifestyle choices^[20]. Key steps include^[18]^[20]:

Don’t smoke. If you smoke, quitting will lower your risk for stroke. Your doctor can suggest ways to help you quit.
Eat a healthy diet. Eat plenty of fresh fruits and vegetables. Choose foods low in saturated fats, cholesterol and salt. Limiting salt in your diet can help lower your blood pressure.
Stay at a healthy weight. Being overweight or obese increases your risk for stroke. Losing as little as 10 pounds can have a real impact on your stroke risk.
Get regular physical activity. Try to get at least 30 minutes of activity a day, and more if possible. Physical activity helps you stay at a healthy weight and lowers your cholesterol and blood pressure levels.
Limit alcohol. Avoid drinking too much alcohol, which can raise your blood pressure. Men should have no more than two drinks per day, and women should have no more than one per day.

If you have already had a stroke or TIA, although your risk of having another stroke is higher, you can reduce your risk. It’s important that you take the medication you’re prescribed and make any lifestyle changes you need^[22].

Recovery and life after stroke

Recovery from ischaemic stroke varies widely between patients. Some people will recover fully from an ischaemic stroke. Others will experience disability afterward, and still others will die from the event^[7]. The effects of a stroke depend on which part of the brain was damaged and how much damage occurred^[5].

Rehabilitation

After treatment, rehabilitation can help you regain lost skills and independence^[6]. Recovery can be a long process of relearning just about everything—from speaking, reading and walking to how to eat independently^[17]. Starting the right rehabilitation program as soon as possible may help survivors recover better^[17].

Your rehabilitation program should be designed for you and address each challenge you face after stroke^[17]. Rehabilitation may include physical therapy, occupational therapy and speech therapy^[17].

Daily living

A stroke is a life-changing event—physically and emotionally. It can make everyday activities challenging^[16]. These challenges may be due to several stroke-related conditions, such as limb weakness, numbness or paralysis, communication challenges, or vision challenges^[16].

Getting dressed, making a meal, doing laundry, or staying organized for the week may become big obstacles. Simple everyday tasks may need to be relearned and you may need more frequent rest breaks^[16]. Every stroke is unique, and your recovery will be too. Ask your doctor or stroke nurse about the help and support available to you^[22].