Brain aneurysms

A brain aneurysm is a weak or thin spot on a blood vessel in the brain that balloons out and fills with blood. The bulging aneurysm can put pressure on a nerve or surrounding brain tissue.

When a brain aneurysm leaks or ruptures it can cause bleeding into the brain which can lead to a stroke or death.

A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment. If you think you may be experiencing an aneurysm, call 911 immediately.


Types of aneurysms

Unruptured aneurysm

A brain aneurysm that does not rupture may produce no symptoms. A larger unruptured aneurysm may press on brain tissues and nerves. It could cause:

  • Pain above and behind one eye

  • A dilated pupil

  • Change in vision or double vision

  • Numbness of one side of the face

Ruptured aneurysm

A sudden, severe headache is the key symptom of a ruptured aneurysm. This headache is often described as the “worst headache” ever experienced. Other symptoms could include:

  • Sudden, extremely severe headache

  • Nausea and vomiting

  • Stiff neck

  • Blurred or double vision

  • Sensitivity to light

  • Seizure

  • A drooping eyelid

  • Loss of consciousness

  • Confusion

Risk factors

Who is at risk

Brain aneurysms can occur in anyone and at any age. They are more common in adults than children and more common in women than in men. The following can also increase the risk:

  • Older age

  • Cigarette smoking

  • High blood pressure

  • Atherosclerosis

  • Heavy alcohol consumption

  • Drug abuse, particularly the use of cocaine

  • Family history of brain aneurysms

  • Fibromuscular dysplasia

  • Inherited connective tissue disorder

  • Polycystic kidney disease

  • Marfan’s syndrome

  • Ehlers-Danlos syndrome

  • Neurofibromatosis type 1


Expert care

If your doctor thinks you may be experiencing an aneurysm, they may request an angiogram. An angiogram is used to look at the blood vessels in your brain and will show any blockage.

The treatment chosen will depend on which blood vessel the aneurysm is growing from and the size and shape. Other key factors will also be your family history and your own health history. The goal is to close off the aneurysm so it does not continue to bleed or rebleed.

The two main treatments for brain aneurysms are:


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