An aneurysm occurs when an artery’s wall weakens and causes an abnormally large bulge.

Arteries are blood vessels that carry blood from the heart to the rest of the body, while veins bring blood back to the heart and lungs. This bulge can rupture and cause internal bleeding. Although an aneurysm can develop in any part of your body, they’re most common in the:

  • Brain. Aneurysms in the brain are called cerebral aneurysms. These often form in the blood vessels that lie deep within the brain. They also may not present any symptoms. You may not even know you have an aneurysm. Cerebral aneurysms may affect 3 to 5 percent of people during their lifetime.
  • Aorta. Aneurysms in the chest cavity are called thoracic aortic aneurysms. Abdominal aortic aneurysms are the most common type. In rare cases, arterial damage can affect both the chest and abdomen.

The aorta is the largest blood vessel in the body. It begins at the left ventricle of the heart and travels down the abdomen where it splits off into both legs. The aorta is a common site for arterial aneurysms.

Other more common areas where an aneurysm may occur include the:

  • legs
  • spleen
  • behind your knee
  • intestines

According to the National Heart, Lung and Blood Institute, aortic aneurysms are responsible for about 13,000 deaths each year in the United States.

Although the exact cause of an aneurysm is unclear, certain factors contribute to the condition.

For example, damaged tissue in the arteries can play a role. Blockages, such as fatty deposits, can harm the arteries. These deposits can trigger the heart to pump harder than necessary to push blood past the fatty buildup. This added stress due to the increased pressure can damage the arteries.

Atherosclerotic disease

Atherosclerotic disease can also lead to an aneurysm. People with atherosclerotic disease have a form of plaque buildup in their arteries. Plaque is a hard substance composed of cholesterol, fat, and other substances that damages the arteries and prevents blood from flowing freely.

High blood pressure

High blood pressure may also cause an aneurysm. The force of your blood as it travels through your blood vessels is measured by how much pressure it places on your artery walls. If the pressure increases above a normal rate, it may enlarge or weaken the blood vessels.

Blood pressure for an adult is considered normal at or below 120/80 mm Hg, or millimeters of mercury.

A significantly higher blood pressure can increase the risk for heart, blood vessel, and circulation problems. However, higher-than-normal blood pressure doesn’t necessarily put you at risk for an aneurysm.

Other risk factors

The type of aneurysm that can affect you depends on specific risk factors. Males are more likely to have aneurysms than females. People 65 and older are also at a higher risk. Other factors may include:

  • a diet high in fats and cholesterol
  • a family history of heart conditions, including heart disease and heart attack
  • smoking
  • obesity
  • pregnancy, which may increase your risk of having an aneurysm of the spleen

Symptoms of an aneurysm vary with each type and location. It’s important to know that aneurysms that occur in the body or brain generally don’t present signs or symptoms until they rupture.

Symptoms of a ruptured aneurysm

Aneurysms that occur near the surface of the body may show signs of swelling and pain. A large mass may also develop. The symptoms of ruptured aneurysm vary, based on its location.

Cerebral aneurysm

Symptoms of a ruptured aneurysm in the brain begin with a sudden and excruciating a headache. Other symptoms may include:

  • vision problems, such as double vision
  • sensitivity to light
  • nausea and vomiting
  • loss of consciousness

Aortic aneurysm

Symptoms of an aortic aneurysm depend on whether it occurs in the chest or the abdomen.

When a thoracic aortic aneurysm ruptures, symptoms may include:

  • sudden and severe chest pain
  • sudden back pain
  • significant drop in blood pressure
  • numbness in the limbs

An abdominal aortic aneurysm that ruptures may cause the following symptoms:

  • sudden and severe pain in the abdomen or lower back
  • rapid heart rate
  • dizziness or lightheadedness
  • shortness of breath
  • cold sweat
Medical emergency

Serious complications from aneurysms can cause death if you don’t get emergency care. Call 911 or have someone drive you to the nearest emergency room if you experience the following symptoms:

  • bleeding
  • increased heart rate
  • shortness of breath
  • sudden chest pain
  • sudden abdominal pain
  • feeling dizzy or light-headed

This is especially important if you know you have an aneurysm. If you’ve been diagnosed with a cerebral aneurysm that hasn’t burst, you should have a procedure to prevent sudden rupture. In some cases, aneurysms in the aorta and elsewhere in the body may be treated with medications and monitored if they don’t appear to be at high risk of rupturing soon.

What is a leaking aneurysm?

Blood can escape an aneurysm without it rupturing. A leaking aneurysm occurs when a small amount of blood is discharged through the thinning wall of the artery. This event is sometimes known as a “sentinel bleed” because it often precedes a more significant aneurysm rupture.

Symptoms of a leaking aneurysm are similar to those of a ruptured aneurysm, though they may not be as severe. A leaking aneurysm in the brain can sometimes trigger what is called a “sentinel headache,” a warning sign that a potentially fatal cerebral hemorrhage may be developing soon.

The diagnostic tools used to find arterial damage often depend on the location of the problem.

Most cerebral aneurysms are found incidentally, often when brain imaging is used to look for other conditions, such as a concussion. Your doctor may refer you to a specialist like a cardiothoracic or vascular surgeon.

A CT scan and ultrasound are common imaging tests used to diagnose or find blood vessel irregularities. CT scans use X-rays to examine the inside of your body. This allows your doctor to see the condition of the blood vessels, as well as any blockages, bulges, and weak spots that may be inside the blood vessels.

Treatment typically depends on the location and type of aneurysm.

For example, a weakened area of a vessel in your chest and abdomen may require a type of surgery called an endovascular stent graft. This minimally invasive procedure may be used over traditional open surgery because it involves repairing and reinforcing damaged blood vessels. The procedure also reduces the chance of infection, scarring, and other problems.

Other treatments can include medications that treat high blood pressure and high cholesterol. Certain types of beta-blockers may also be prescribed to lower blood pressure. Lowering your blood pressure may keep your aneurysm from rupturing.

Eating a nutrient-rich diet containing plenty of fruits, whole grains, and vegetables may help prevent an aneurysm from forming. Meat and poultry low in saturated fat and cholesterol are also good protein options. Low fat dairy products are also beneficial.

Incorporating regular exercise into your routine, especially cardio, can encourage healthy blood circulation and blood flow through the heart, arteries, and other blood vessels.

If you smoke tobacco products, consider quitting. Eliminating tobacco can decrease your risk of an aneurysm. Quitting can be challenging, but a healthcare professional can help you build a cessation plan that works for you and connect you with other supportive resources.

Scheduling annual checkups is another way to be proactive about helping prevent an aneurysm. It’s also a way to help promote overall health and well-being.

An aneurysm is a bulge that forms in the thinning wall of an artery. Two of the most common and potentially life threatening locations for an aneurysm are the brain (cerebral aneurysm) and the aorta, the largest blood vessel in the body.

If an aneurysm ruptures, it is a medical emergency. Though an aneurysm can’t always be prevented, taking steps such as maintaining a healthy blood pressure, quitting smoking, and scheduling annual checkups can help lower your risks.