Brain aneurysm
Find out what a brain aneurysm is, including why they develop, who's affected, how they're treated and how to prevent them.
A brain aneurysm rarely causes any symptoms unless it bursts (ruptures).
Brain aneurysms are caused by a weakness in the walls of blood vessels in the brain. There are several reasons why this may happen, although an exact cause isn't always clear.
A brain aneurysm is usually diagnosed using a magnetic resonance imaging (MRI) scan or a computerised tomography (CT) scan.
Brain aneurysms can be treated using surgery if they've burst (ruptured) or there's a risk they will.
You can't always prevent brain aneurysms, but you can lower your risk by not smoking and reducing high blood pressure.