An aneurysm (AN-u-rism) is a balloon-like bulge in an artery. Arteries are blood vessels that carry oxygen-rich blood from your heart to your body.
Arteries have thick walls to withstand normal blood pressure. However, certain medical problems, genetic conditions, and trauma can damage or injure artery walls. The force of blood pushing against the weakened or injured walls can cause an aneurysm.
An aneurysm can grow large and burst (rupture) or cause a dissection. Rupture causes dangerous bleeding inside the body. A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall.
Both conditions are often fatal.
Most aneurysms occur in the aorta, the main artery that carries oxygen-rich blood from the heart to the body. The aorta goes through the chest and abdomen.
An aneurysm that occurs in the chest portion of the aorta is called a thoracic (tho-RAS-ik) aortic aneurysm. An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm.
Aneurysms also can occur in other arteries, but these types of aneurysm are less common. This article focuses on aortic aneurysms.
About 13,000 Americans die each year from aortic aneurysms. Most of the deaths result from rupture or dissection.
Early diagnosis and treatment can help prevent rupture and dissection. However, aneurysms can develop and grow large before causing any symptoms. Thus, people who are at high risk for aneurysms can benefit from early, routine screening.
Doctors often can successfully treat aortic aneurysms with medicines or surgery if they’re found in time. Medicines may be given to lower blood pressure, relax blood vessels, and reduce the risk of rupture.
Large aortic aneurysms often can be repaired with surgery. During surgery, the weak or damaged portion of the aorta is replaced or reinforced.
Types of Aneurysm
The two types of aortic aneurysm are abdominal aortic aneurysm and thoracic aortic aneurysm. Some people have both types.
Abdominal Aortic Aneurysms
An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm (AAA). Most aortic aneurysms are AAAs.
These aneurysms are found more often now than in the past because of computed tomography (to-MOG-rah-fee) scans, or CT scans, done for other medical problems.
Small AAAs rarely rupture. However, AAAs can grow very large without causing symptoms. Routine checkups and treatment for an AAA can help prevent growth and rupture.
Thoracic Aortic Aneurysms
An aneurysm that occurs in the chest portion of the aorta (above the diaphragm, a muscle that helps you breathe) is called a thoracic aortic aneurysm (TAA).
TAAs don't always cause symptoms, even when they're large. Only half of all people who have TAAs notice any symptoms. TAAs are found more often now than in the past because of chest CT scans done for other medical problems.
With a common type of TAA, the walls of the aorta weaken and a section close to the heart enlarges. As a result, the valve between the heart and the aorta can't close properly. This allows blood to leak back into the heart.
A less common type of TAA can develop in the upper back, away from the heart. A TAA in this location may result from an injury to the chest, such as from a car crash.
Other Types of Aneurysms
When an aneurysm occurs in an artery in the brain, it's called a cerebral (seh-RE-bral or SER-eh-bral) aneurysm or brain aneurysm. Brain aneurysms also are sometimes called berry aneurysms because they're often the size of a small berry.
Most brain aneurysms cause no symptoms until they become large, begin to leak blood, or rupture. A ruptured brain aneurysm causes a stroke.
Aneurysms that occur in arteries other than the aorta and the brain arteries are called peripheral aneurysms. Common locations for peripheral aneurysms include the popliteal (pop-li-TE-al), femoral (FEM-o-ral), and carotid (ka-ROT-id) arteries.
The popliteal arteries run down the back of the thighs, behind the knees. The femoral arteries are the main arteries in the groin. The carotid arteries are the two main arteries on each side of your neck.
Peripheral aneurysms aren't as likely to rupture or dissect as aortic aneurysms. However, blood clots can form in peripheral aneurysms. If a blood clot breaks away from the aneurysm, it can block blood flow through the artery.
If a peripheral aneurysm is large, it can press on a nearby nerve or vein and cause pain, numbness, or swelling.
Other Names for Aneurysm
- Abdominal aortic aneurysm
- Aortic aneurysm
- Berry aneurysm
- Brain aneurysm
- Cerebral aneurysm
- Peripheral aneurysm
- Thoracic aortic aneurysm
Read more about this topicfrom this and related documents at the National Heart, Lung and Blood Institute.