Risk factors

A number of factors can contribute to weakness in an artery wall and increase the risk of a brain aneurysm or aneurysm rupture. Brain aneurysms are more common in adults than in children and more common in women than in men.

Some of these risk factors develop over time; others are present at birth.

Risk factors that develop over time

These include:

• Older age
• Cigarette smoking
• High blood pressure (hypertension)
• Drug abuse, particularly the use of cocaine
• Heavy alcohol consumption

Some types of aneurysms may occur after a head injury (dissecting aneurysm) or from certain blood infections (mycotic aneurysm).

Risk factors present at birth

Selected conditions that date to birth can be associated with an elevated risk of developing a brain aneurysm. These include:

• Inherited connective tissue disorders, such as Ehlers-Danlos syndrome, that weaken blood vessels
• Polycystic kidney disease, an inherited disorder that results in fluid-filled sacs in the kidneys and usually increases blood pressure
• Abnormally narrow aorta (coarctation of the aorta), the large blood vessel that delivers oxygen-rich blood from the heart to the body
• Cerebral arteriovenous malformation (brain AVM), an abnormal connection between arteries and veins in the brain that interrupts the normal flow of blood between them
• Family history of brain aneurysm, particularly a first-degree relative, such as a parent, brother, sister, or child