What occurs when the blood supply to a part of your brain?

A stroke occurs when the blood supply to a part of your brain is suddenly reduced. This prevents that part of your brain from getting oxygen and other nutrients from your blood. A stroke is a medical emergency.

Your brain needs a continuous supply of oxygen and nutrients from blood, supplied by your arteries — without oxygen or nutrients, your brain cells will die ('infarct') and the affected area can suffer permanent damage.

There are 2 main reasons for reduced blood supply: a blood clot or a bleed.

At least 3 in every 200 Australians have had a stroke.

Types of stroke

Ischaemic stroke

An ischaemic stroke is when a blood clot blocks blood supply to your brain. If the blood clot happens inside an artery, it blocks oxygen and nutrients from getting to your brain.

There are 2 main types of ischaemic strokes:

• An embolic stroke occurs when a blood clot forms elsewhere in the body (often the heart), travels through the bloodstream, then blocks a blood vessel that supplies your brain.
• A thrombotic (or thrombolytic) stroke occurs when your brain's blood supply is blocked because plaque (accumulated cholesterol, fat or calcium in blood) builds up in your artery walls.

What is a haemorrhagic stroke?

A haemorrhagic stroke occurs when the wall of a blood vessel in the brain suddenly breaks. This causes blood to flood into the brain, blocking the delivery of oxygen and nutrients.

There are 2 types of haemorrhagic strokes:

• An intracerebral haemorrhage (ICH) occurs when an artery in your brain bursts and bleeds.
• A subarachnoid haemorrhage (SAH) occurs when a bleed happens in the space surrounding your brain.

If you suspect you — or another person — might be having a stroke, it's important to get help quickly. Call triple zero (000) immediately and ask for an ambulance.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What are the symptoms of a stroke?

You can remember the main symptoms of stroke by using the word F.A.S.T. If you think someone may be having a stroke, check the following:

• Face — Has their face or mouth drooped?
• Arms — Can they lift both arms?
• Speech — Is their speech slurred? Do they understand you?
• Time is critical — If you see any of these signs, call triple zero (000) immediately and ask for an ambulance. Early treatment could save their life.

Other possible signs of stroke include:

• weakness or paralysis elsewhere in the body, on one or both sides
• loss of sensation, usually on one side
• loss of vision or blurred vision in one or both eyes
• a sudden and severe headache
• dizziness, loss of balance or an unexplained fall
• difficulty swallowing

Remember that a stroke is always a medical emergency. The longer it takes to get treatment, the more likely there will be stroke-related brain damage afterwards.

What causes a stroke?

Ischaemic strokes, clots that block blood flow to your brain, usually come from places where plaque narrows your arteries (a process called atherosclerosis).

Haemorrhagic strokes mainly result from long-term high blood pressure bursting a blood vessel wall, but can also be caused by a cerebral aneurysm (a weak spot in an artery wall that bursts from sudden pressure or trauma).

Common risk factors that increase your blood pressure or cause your arteries to narrow over time include:

• Smoking — Tobacco smoke deposits toxic chemicals in your bloodstream, making your blood sticky and more likely to form clots.
• Not enough physical activity — Being inactive increases your risk of high blood pressure, type 2 diabetes and other related conditions.
• Unhealthy eating — Too much body fat (obesity) can contribute to high blood pressure and other conditions, while too much salt in your diet increases blood pressure.
• High cholesterol — Excess low-density lipoprotein ('bad' cholesterol) in your blood can build up on artery walls.
• Certain medical conditions, such as type 2 diabetes and atrial fibrillation (an irregular heartbeat).

There are also factors you can't change that increase your risk of a stroke, such as:

• Your age — Most people who have a stroke (7 out of 10) are 65 years or older.
• Your family history — If one of your parents had a stroke before they were 65, your risk of getting one is 3 times greater than average.
• Your gender — Stroke is more common in men, especially between 65 and 84 years of age.

ARE YOU AT RISK? — Are you at risk of type 2 diabetes, heart disease or kidney disease? Use our Risk Checker to find out.

What is a transient ischaemic attack?

A transient ischaemic attack, also known as a TIA or 'mini-stroke', causes stroke-like symptoms for a few minutes and disappears within 24 hours. It’s caused by a temporary blockage to your brain’s blood supply and means you have a higher chance of experiencing a stroke.

If you experience a TIA, see your doctor urgently so you can reduce your chance of an ischaemic stroke.

How is a stroke diagnosed?

Your doctor will diagnose a stroke by conducting a physical examination and reviewing images of your brain. In hospital, doctors will carry out tests to check whether you have had a stroke, or have another condition. If it’s a stroke, they will work out what kind of stroke it is, find out which part of your brain is affected and decide how to treat it.

You might need different tests. Some common ones include:

Some illnesses that are unrelated to stroke may show stroke-like symptoms and require different treatments. These include migraine, seizures, low blood sugar, fainting and heart arrhythmias.

How is a stroke treated?

The exact treatment depends on what caused your stroke, but generally involves both immediate and long-term measures.

Immediate stroke treatment

For ischaemic strokes, the blood clot needs to be dissolved using medication, or removed. Small blood clots may be dissolved with medication. Large clots usually require brain surgery such as endovascular clot retrieval (mechanical thrombectomy), where a catheter is threaded up your blood vessels to find and remove the clot.

For haemorrhagic strokes, immediate treatment involves intensive blood pressure control and surgery to relieve swelling from bleeding in the brain, or to repair the ruptured blood vessel.

Long-term stroke treatment

Treatments to prevent another stroke or TIA include:

Can strokes be prevented?

More than 4 in 5 strokes are preventable. If you have high blood pressure, type-2 diabetes, high cholesterol or an irregular heartbeat (atrial fibrillation), see your doctor for ways to manage these stroke risk factors using medication.

You can also reduce your risk by maintaining a healthy lifestyle, including by staying active, eating well, quitting smoking and drinking alcohol in moderation.

If you've already had a stroke or TIA, it's even more important to make the following lifestyle changes:

• Improve your diet — A diet that's varied, high in fibre, fruit, nuts, vegetables and healthy fats, but low in saturated fat and salt, can help prevent stroke.
• Avoid smoking — Smoking cigarettes doubles your risk of having a stroke.
• Regular exercise — This helps you maintain a healthy weight and improve blood circulation.

A stroke can be fatal — every day, 23 Australians die from a stroke. Among those who survive, 1 in 3 will have a long-term disability due to their stroke and are likely to always need help with talking, moving and self-care.

Long-term complications of a stroke may include:

• weakness or lack of movement (paralysis) in your limbs
• difficulty speaking or swallowing
• difficulty reading or writing
• shoulder pain
• feeling tired (fatigue) or depressed
• changes to how things feel when you touch them (sensory problems)
• changes to how you see or understand things (perceptual problems)
• problems thinking or remembering (cognitive problems)
• problems with bowel or bladder control (incontinence)
• problems controlling your feelings and emotions

Complete recovery is often possible since the brain learns to compensate for any damage. However, many people never fully regain their former abilities.

Life after a stroke

Post-stroke care may include rehabilitation in a hospital setting, outpatient therapy and home therapy. Sometimes a long-term care facility may be the best option. Physiotherapists, occupational therapists, speech pathologists and psychologists can all help you regain your ability to function.

Depression is common among people who have had a stroke. You may not feel motivated to take medication or complete physical rehabilitation. Depending on which part of your brain is affected, changes in personality and mood can develop, which can distress family members and close friends.

It’s important to try and return to normal life where possible, such as resuming some kind of work and engaging in your favourite activities, hobbies and interests.

What occurs when the blood supply to a part of your brain interrupted?

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