Brain aneurysm
An aneurysm is a bulge in a blood vessel. It’s caused by a weakness in the blood vessel wall, usually where it branches. A brain aneurysm rarely causes any symptoms, unless it bursts (ruptures).
About aneurysms
An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall, usually where it branches.
As blood passes through the weakened blood vessel, the blood pressure causes a small area to bulge outwards like a balloon.
Aneurysms can develop in any blood vessel in the body, but the two most common places are:
- the abdominal aorta – the artery that transports blood away from the heart to the rest of the body
- the brain
Symptoms of a brain aneurysm
A brain aneurysm rarely causes any symptoms unless it bursts (ruptures).
Unruptured brain aneurysms occasionally cause symptoms if they're particularly large or press against tissues or nerves inside the brain.
Symptoms of an unruptured brain aneurysm can include:
- visual disturbances – such as loss of vision or double vision
- pain above or around your eye
- numbness or weakness on one side of your face
- difficulty speaking
- headaches
- loss of balance
- difficulty concentrating or problems with short-term memory
You should see your GP as soon as possible if you experience symptoms of an unruptured brain aneurysm.
Although most aneurysms won't rupture, it's important to get it checked in case treatment is necessary.
Ruptured brain aneurysm
Symptoms of a ruptured brain aneurysm usually begin with a sudden agonising headache. It's been likened to being hit on the head. This results in a blinding pain unlike anything experienced before.
Other symptoms of a ruptured brain aneurysm also tend to come on suddenly.
They may include:
- feeling sick or vomiting
- stiff neck or neck pain
- sensitivity to light
- blurred or double vision
- sudden confusion
- loss of consciousness
- seizures (fits)
- weakness on one side of the body, or on any limbs
Medical emergency
A ruptured brain aneurysm is a medical emergency.
Call 999 immediately and ask for an ambulance if someone is experiencing symptoms of a ruptured brain aneurysm.
How brain aneurysms are treated
If a brain aneurysm is detected before it ruptures, treatment may be recommended.
This is to prevent it rupturing in future. Most aneurysms won't rupture, so treatment is only carried out if the risk of a rupture is particularly high.
The same treatment used to prevent ruptures are also used to treat brain aneurysms that have already ruptured.
Why brain aneurysms develop
Exactly what causes the wall of affected blood vessels to weaken is still unclear, although risk factors have been identified, including:
- smoking
- high blood pressure
- a family history of brain aneurysms
In some cases, an aneurysm may develop because there was a weakness in the walls of the blood vessels at birth.
Who is affected
It's difficult to estimate how many people are affected by brain aneurysms. This is because they usually cause no symptoms and pass undetected.
Brain aneurysms can develop in anyone at any age. But they are more common in people over the age of 40.
Women tend to be affected more commonly than men.
Preventing brain aneurysms
The best way to prevent getting an aneurysm, or reduce the risk of an aneurysm growing bigger and possibly rupturing, is to avoid things that could damage your blood vessels.
These include:
- smoking
- eating a high-fat diet
- not controlling high blood pressure
- being overweight or obese
More useful links
The information on this page has been adapted from original content from the NHS website.
For further information see terms and conditions.