Cerebral (Brain) Aneurysm

A brain aneurysm is bulging or ballooning of an artery supplying blood to the brain.


Brain aneurysm

Aneurysms typically form where an artery branches or turns and where the wall of the vessel is weak. This weakness may be genetic or the result of environmental factors like atherosclerosis, tobacco use and/or high blood pressure.  Brain aneurysms may be present in up to 5% of the population. Aneurysms themselves typically do not cause any symptoms but problems occur when they rupture, bleed or grow large.


Unruptured aneurysms rarely cause any symptoms, including headaches. If an aneurysm becomes very large, it may cause symptoms because it presses on the brain or the nerves around it.

When an aneurysm ruptures, however, the most common symptoms are:

  • Severe, sudden onset headache
  • Vomiting
  • Neck pain
  • Sensitivity to light

These symptoms may quickly progress to loss of consciousness, coma and even death in severe cases.


Most unruptured aneurysms are diagnosed on a CT or MRI scan taken for unrelated reasons. Sometimes, when we discover one, we may recommend a diagnostic cerebral angiogram (LINK) for further evaluation.

Treatment Options

Most unruptured aneurysms do not require treatment but it’s essential that anyone with a newly diagnosed cerebral aneurysm be evaluated by a neurosurgeon specializing in cerebrovascular conditions or a neurointerventionalist.

Your specialist might opt to use surveillance imaging to ensure the aneurysm remains stable in size and shape.  However, depending the aneurysm’s size and location, plus such patient factors as age and other medical conditions, some require treatment to minimize the risk of rupture.

Treatment options depend on aneurysm size, shape and location, and patient age, medical condition and preference. Options include:

  • Surgical clipping
  • Endovascular therapies

Ayer Neuroscience Institute