What is a brain aneurysm?

A brain aneurysm (also known as a cerebral or intracranial aneurysm) is a bulge in an artery in your brain. It’s caused by a weak area in your artery wall.

If a brain aneurysm bursts, it can cause bleeding in your brain. This can quickly become life-threatening.

There are different types of brain aneurysm. The most common type is called a saccular (or ‘berry’) aneurysm.

About 3 in 100 people have a brain aneurysm. It is more common as you get older. Aneurysms can also occur elsewhere in your body.

What are the symptoms of a brain aneurysm?

Many people have a brain aneurysm without realising it. It may only be found when you have a brain scan for another reason. Usually there are no symptoms unless it bursts.

Sometimes, if an aneurysm becomes very large, it can cause:

• headache
• dizziness
• vision changes
• difficulty with eye movements
• pain in your face

What are the warning signs?

When an aneurysm bursts, it can cause:

• a sudden, very severe headache
• nausea and vomiting
• neck pain
• feeling sensitive to light
• loss of consciousness — this may occur briefly when the headache starts, or it may lead to coma

Sometimes, a small amount of bleeding from a brain aneurysm causes a sudden, severe headache that may get better. This is often a sign that the aneurysm is about to burst.

When should I call an ambulance or go to the emergency department?

If you or someone near you has a sudden, severe headache or becomes unconscious, call triple zero (000) and ask for an ambulance.

What should I do while waiting for the ambulance?

While waiting for the ambulance, follow any instructions given to you by the triple zero (000) call taker.

When should I see my doctor?

Talk to your doctor about getting tested for brain aneurysms if you are at risk. Your doctor may arrange for you to have a brain scan if you have a family history of brain aneurysms. If you find an aneurysm early, you can have treatment before it bursts.

What causes a brain aneurysm?

Aneurysms develop when your artery wall becomes weakened. This may be caused or exacerbated by:

• high blood pressure — this puts extra strain on the walls of your arteries
• smoking — this leads to changes in the walls of your arteries
• atherosclerosis
• a head injury
• infection
• genetics

Exercise does not cause aneurysms to develop, however it can sometimes cause an aneurysm to burst.

Risk factors

You are more likely to develop a brain aneurysm if you:

• have a family history of brain aneurysms
• have a connective tissue disease, such as Ehlers-Danlos syndrome
• have polycystic kidney disease
• smoke
• have high blood pressure

How is a brain aneurysm diagnosed?

A brain aneurysm can be found on a brain scan such as CT scan or an MRI. It may be found accidentally, if you have a brain scan for other reasons. During the scan, you may have an injection of dye into your vein to show the blood vessels in your brain clearly.

If an aneurysm is suspected, you may have an angiogram. This is where a thin tube is inserted into an artery. A special dye is injected to show detailed information about the aneurysm.

Ruptured aneurysm

If your doctor suspects that your aneurysm has burst, they will arrange an urgent CT scan of your brain to confirm the diagnosis.

If the CT scan doesn’t show any bleeding, your doctor might do a lumbar puncture. This involves taking a sample of the fluid that surrounds your brain and spinal cord using a thin needle. If you have a burst brain aneurysm, you might have blood or other signs in your spinal fluid.

How is brain aneurysm treated?

If you have a brain aneurysm that is not causing any symptoms, treatment options will depend on its size and location and whether you are at a high risk of rupture.

If your aneurysm is very small, treatment might include:

• regular monitoring scans to check if it is growing
• treatment for high blood pressure
• stopping smoking

If your aneurysm is growing or causing symptoms, or if you are at higher risk of rupture, your doctor may suggest surgery to prevent the aneurysm from bursting in the future. This may involve putting a metal clip over the aneurysm, or putting a tiny metal coil into the aneurysm through your vein.

Ruptured aneurysm

If your aneurysm has burst, you will need urgent surgery to clip the aneurysm or put in a coil so that it does not bleed again. Your treating team will also control your blood pressure to prevent more bleeding.

Someone who is unconscious will first need medical treatment in hospital to stabilise their condition before surgery to treat the aneurysm.

What are the complications of a brain aneurysm?

If a brain aneurysm bursts and bleeds, it can cause a stroke. This can lead to sudden death or permanent disability.

Complications of a burst brain aneurysm may include:

• reduced blood flow in your brain, leading to brain injury (stroke)
• fluid on your brain (called hydrocephalus)
• high pressure in your brain
• seizures
• heart or lung problems

Can a brain aneurysm be prevented?

You may be able to reduce the chance of some brain aneurysms forming by:

• getting exercise (ask your doctor before starting to exercise)
• quitting smoking
• reducing the amount of alcohol you drink
• keeping your blood pressure under control

If you have been diagnosed with a brain aneurysm, you can take these steps to reduce the chance of it bursting:

• Quit smoking and avoid exposure to smoke.
• Reduce your alcohol intake.
• Take any medicines you have been prescribed for high blood pressure.
• Avoid lifting weights and doing strenuous exercise. Talk to your doctor about exercise that is safe for you.
• Do not use drugs or stimulant medicines.

Resources and support

Call Quitline on 13 7848 for information and help with quitting smoking.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.

Other languages

The Department of Health and Aged Care has videos about quitting smoking in a range of community languages.

Read more about quitting smoking in a range of community languages from Health Translations Victoria.

Aboriginal and/or Torres Strait Islander peoples

Find support for quitting smoking for Aboriginal and/or Torres Strait Islander people at iCanQuit.