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What is an aneurysm?

An aneurysm is an abnormal widening or ballooning of an artery due to weakness in the wall of the blood vessel. Aneurysms are dangerous because they may burst, spilling blood in the area surrounding the blood vessel. The disease can occur in the aorta, in a blood vessel in the brain, or in a peripheral blood vessel.

An aneurysm can occur in any artery in the body but commonly occurs in the aorta, the largest artery in the body, which leads from the heart into the abdomen. Aortic aneurysms are most commonly found in the abdominal cavity (known as abdominal aortic aneurysms) but may also occur in the chest or thoracic cavity, where they are known as thoracic aortic aneurysms. Most commonly, people who develop aortic aneurysms are Caucasian, male, older than 60 years, and have high blood pressure, atherosclerosis, or a family history of aneurysm. Cigarette smoking is also a known risk factor for the development of aortic aneurysm. Abdominal aortic aneurysms are estimated to occur in 1.3% of men aged 45 to 54 years of age and 12.5% of men between 75 and 84 years of age in the United States (Source: CDC).

Brain aneurysms are estimated to occur in approximately 30,000 people in the United States (Source: AANS).

Peripheral artery aneurysms most commonly occur in the popliteal artery (behind the knees), the mesenteric artery (intestine), femoral artery (groin) and splenic artery (spleen).

The signs and symptoms of an aneurysm depend on its location. The disease course varies among individuals. Some people with an aneurysm have no symptoms at all, but if the aneurysm ruptures, internal bleeding occurs, potentially causing pain, low blood pressure, a rapid heartbeat, and lightheadedness.

When an aneurysm bursts inside the skull (intracranial aneurysm), individuals report ”the worst headache of their life” followed by rapidly progressive rapid decline in alertness, mental function, and other neurologic functions. If the aneurysm occurs near the surface of the skin, pain and swelling with a throbbing mass are often felt.

Fortunately, aneurysms can be treated successfully with a range of options such as lifestyle changes, high blood pressure management, or surgery.

Left untreated, an aneurysm may rupture. Rupture of an artery can result in life-threatening bleeding. Seek immediate medical care (call 911) if you, or someone you are with, have symptoms of a ruptured aneurysm, such as severe back pain, sudden severe headache, rapid heart rate, difficulty swallowing, blurred vision, cold skin, or loss of consciousness.

What are the symptoms of an aneurysm?

Aneurysms can develop slowly over many years. Many people have no symptoms, while others may experience a number of symptoms that vary in intensity among individuals depending on the location, rate of growth, and size of the aneurysm.

Common symptoms of an intracranial aneurysm

Aneurysms typically do not produce symptoms. However, if an intracranial aneurysm ruptures, any of these aneurysm symptoms may occur and can be severe:

Serious symptoms that might indicate a life-threatening condition

In some cases, aneurysms can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

What causes an aneurysm?

Aneurysms are caused by weakness in the wall of a cerebral artery or vein, aortic artery, or peripheral artery. The disorder may result from defects present at birth (congenital), from underlying conditions such as hypertensive vascular disease and atherosclerosis (buildup of fatty deposits in the arteries), or from previous trauma to the area of the aneurysm.

High blood pressure, high cholesterol levels, and cigarette smoking may raise the risk of certain types of aneurysms. High blood pressure and smoking are known to contribute to the formation of abdominal aortic aneurysms. Atherosclerotic disease (cholesterol buildup in arteries) may also lead to the formation of some aneurysms. Pregnancy is often associated with the development and rupture of splenic artery aneurysms.

Inherited conditions that affect the connective tissues of the body, such as Marfan’s syndrome, also increase your risk of developing certain types of aneurysms.

What are the risk factors for an aneurysm?

A number of factors increase the risk of developing an aneurysm. Not all people with risk factors will get an aneurysm. Risk factors for aneurysm include:

  • Advanced age
  • Atherosclerosis (buildup of plaque on the walls of the coronary arteries; atherosclerosis is a type of arteriosclerosis)
  • Caucasian race
  • Estrogen deficiency from menopause
  • Family history
  • Genetic diseases of connective tissue, such as Marfan’s syndrome
  • High blood pressure
  • Male gender
  • Pre-existing blood vessel malformations
  • Smoking or other tobacco use

Reducing your risk of aneurysm

You may be able to lower your risk of an aneurysm by:

  • Getting regular physical activity
  • Keeping your cholesterol at a healthy level
  • Maintaining normal blood pressure
  • Reducing the amount of cholesterol and fat in your diet
  • Quitting smoking and other tobacco use

How is an aneurysm treated?

Treatment for aneurysms begins with seeking medical care from your health care provider. To determine if you have an aneurysm, your health care provider will ask you to undergo several diagnostic tests.

Treatment of an aneurysm depends on the size, location, and type of aneurysm. An expanding or enlarging aneurysm in the aorta often requires emergency treatment, and surgery is generally recommended. Which type of surgery and when it is needed it will depend on the symptoms and the size and type of aneurysm. Some people may have endovascular stent repair. A stent is a tiny tube placed within a blood vessel to keep the vessel open or reinforce its wall.

Some types of aneurysms that are small or not life threatening may be carefully watched by a doctor or health care provider. Such observation requires regular medical care and testing. Ultrasound imaging is used to monitor potential growth of the aneurysm. The decision of whether to perform surgery requires balancing the risk of surgical complications against the risk of complications from the aneurysm itself.

Treatments for aneurysm

Common treatments of aneurysm include:

  • Blood pressure management
  • Control of risk factors
  • Observation and monitoring
  • Surgical repair of the aneurysm

What you can do to improve your aneurysm

In addition to following your health care provider’s instructions and taking all medications as prescribed, you can reduce your risk by:

  • Eating a heart-healthy diet that includes potassium and fiber and drinking plenty of water
  • Exercising at least 30 minutes a day
  • Limiting alcohol consumption to 1 drink a day for women, 2 a day for men
  • Limiting the amount of sodium (salt) you eat (less than 1,500 mg per day)
  • Maintaining a healthy body weight
  • Quitting smoking
  • Reducing stress

What are the potential complications of an aneurysm?

You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of aneurysm include:

  • Blood clots
  • Compression of nerves or other adjacent structures, causing weakness and numbness (occurs most commonly with aneurysms that develop in the artery behind the knee)
  • Hypovolemic shock (a state of low blood pressure caused by bleeding or other fluid loss)
  • Organ failure
  • Rupture of the aneurysm
  • Severe internal bleeding
  • Stroke
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 9
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Types of Aneurysms. American Heart Association.
  2. What is an aneurysm? American Heart Association.

  3. Sato K, Yoshimoto Y. Risk profile of intracranial aneurysms: rupture rate is not constant after formation. Stroke 2011; 42:3376.