Aneurysm: Symptoms and Causes

An aneurysm (AN-u-rism) is a balloon-like bulge in an artery. Arteries are blood vessels that carry oxygen-rich blood 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 rupture (burst) or dissect. A 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 rupture and dissection often are fatal.


Symptoms

Most aneurysms are clinically silent. Symptoms do not usually occur unless an aneurysm ruptures.

However, an unruptured aneurysm may still obstruct circulation to other tissues. They can also form blood clots that may go on to obstruct smaller blood vessels. This is a condition known as thromboembolism. It can lead to ischemic stroke or other serious complications.

Rapidly growing abdominal aneurysms are sometimes associated with symptoms. Some people with abdominal aneurysms report abdominal pain, lower back pain, or a pulsating sensation in the abdomen.

Similarly, thoracic aneurysms can affect nearby nerves and other blood vessels, potentially causing swallowing and breathing difficulties, and pain in the jaw, chest, and upper back.

Symptoms can also relate to the cause of an aneurysm rather than the aneurysm itself. For example, in the case of an aneurysm caused by vasculitis, or blood vessel inflammation, a person may experience fever, malaise, or weight loss.

Causes

An aneurysm can happen in any part of the body. Blood pressure can more easily distend a weakened arterial wall.

Further research is necessary to confirm why an artery wall weakens to cause an aneurysm. Some aneurysms, though less common, are present from birth as an arterial defect.

Aortic dissection

Aortic dissection is one identifiable cause of an aortic aneurysm. The arterial wall has three layers. Blood can burst through a tear in the weakened wall of the artery, splitting these layers. It can then fill the cavity surrounding the heart.

If the tear occurs on the innermost layer of the arterial wall, blood channels into and weakens the wall, increasing the risk of rupture.

People with aortic dissection often describe abrupt and excruciating chest pain. This pain can travel as the dissection progresses along the aorta. It may, for example, radiate to the back.

Dissection leads to compression. Compression prevents blood from returning to the heart. This is also known as a pericardial tamponade.

Risk factors

There are some lifestyle choices and physical characteristics that can increase the chance of an aneurysm.

• smoking tobacco
• hypertension, or high blood pressure
• poor diet
• inactive lifestyle
• obesity

Smoking is by far the most common risk factor, especially in cases of AAA. Tobacco use has been shown not only to increase cardiovascular disease and the risk of an aneurysm but also increase the risk of rupture once an aneurysm has taken effect.

Not all cases of unruptured aneurysm need active treatment. When an aneurysm ruptures, emergency surgery is needed.