What causes an aneurysm?

Aneurysms are caused by a weakening of artery walls. When the force of blood flow pushes against a weakened artery wall, it starts to bulge and form an aneurysm. There are many different genetic conditions, medical conditions, injuries, and lifestyle choices that can increase your risk for developing weakened artery walls.

An aneurysm is a portion of a blood vessel wall that balloons outward. When blood flows through arteries from your heart to the rest of your body, it exerts pressure against the walls of your arteries. (That is what a blood pressure reading measures.) If an artery has a weak spot in its wall, the force of the blood can cause the artery wall to bulge. If an aneurysm in one of the key arteries of your body ruptures, it can lead to sudden death. An aneurysm is especially dangerous if it occurs in the aorta, which carries blood away from your heart; the carotid arteries, which carry blood to the brain; or the abdominal aortic artery, the artery that supplies your lower body with blood.

The causes of aneurysms are not yet fully understood, but some factors are known to increase the likelihood of an aneurysm:
  • A defect in the artery wall that you were born with
  • High blood pressure
  • Atherosclerosis, or narrowing of the arteries from a build-up of a substance called plaque
  • Aging
  • Smoking
  • Genetic factors
  • External trauma from an accident

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.