An aortic aneurysm is a bulging section in the wall of the aorta—the large blood vessel delivering blood from the heart to the body—that has become stretched-out and thin. Where the wall of the blood vessel bulges out, it becomes weaker and may burst or rupture, causing bleeding.

Most aortic aneurysms are caused by a combination of hardening of the arteries (atherosclerosis), genetics, and aging. However, a small number are caused by inflammation or infection.

Aortic aneurysms rarely produce symptoms and are usually found during examinations done for other reasons. When symptoms occur, they most commonly include general complaints of abdominal or chest pain or discomfort, which can come and go or be constant.

Surgery is needed for large or fast-growing aneurysms, or when symptoms are present. Aneurysms caused by inflammation may require antibiotics.