What Is Aneurysm?

doctor analyzes a scan of aneurysm

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An aneurysm is a bulge in an artery, a vessel that sends oxygenated blood from the heart to the rest of the body. It is caused by weaknesses in the walls of these vessels. Several factors raise your risk of having an aneurysm, including high blood pressure and abnormalities at birth.

While most aneurysms occur in the aorta—the large artery that connects the heart to the chest and abdomen—they can occur in any artery. When affecting arteries in the brain, a condition known as cerebral aneurysm, it can cause brain bleeding (hemorrhage) and stroke.

While all genders and ages can be affected, certain types are more prevalent in certain populations. Aneurysm symptoms depend on the severity of the case and its location. In some cases, it ruptures the artery, leading to internal bleeding, which can be dangerous and fatal. Luckily, there are therapies that take on this condition.     

Types of Aneurysm 

Aneurysm is categorized based on the part of the body that’s affected. The type you have helps to determine the symptoms that you have as well as potential complications. The current consensus is that this condition can be broken down into four primary types: thoracic abdominal, aortic abdominal, cerebral, and peripheral aneurysm.

Thoracic Aortic Aneurysm

Aortic aneurysms occur in the aorta, the body’s largest artery, which runs from the heart to the chest walls (thorax) and abdomen. Thoracic aortic aneurysm occurs when the upper portion, or thoracic aorta, is affected. It occurs when the ballooning of the artery leads to a 50% increase in its diameter.

Abdominal Aortic Aneurysm

Abdominal aortic aneurysm occurs in the lower part of the aorta, which brings blood to the walls of the abdomen, pelvis, and legs. In these cases, weaknesses in the artery walls causing it to swell to 150% of its usual size.

Cerebral Aneurysm

Cerebral aneurysm arises when arteries in the brain become swollen and enlarge. Most commonly, people have saccular cerebral aneurysm, in which a blood-filled sac develops, typically near the branches of arteries at the base of the brain. Another sub-type is fusiform aneurysm, in which the ballooning occurs on all sides.  

Peripheral Aneurysm

Peripheral aneurysm occurs when dilation occurs in arteries in the legs (popliteal aneurysm) or abdomen (splenic aneurysm). Very rare, the former affects 0.007% of assigned males at birth and even less assigned females, with splenic aneurysms seen in about 0.7% of the population.  


The symptoms of aneurysm vary based on type and severity. Here’s a quick breakdown of the signs of this condition.

Thoracic Aortic Aneurysm Symptoms  

About 95% of thoracic aortic aneurysms are asymptomatic, but problems can occur if the artery bursts or there are rips in its walls (known as dissection). A lack of symptoms can make thoracic aortic aneurysms dangerous, as complications can arise without warning. Typical symptoms of this type include:

  • Sharp, sudden pain in the chest or upper back
  • Breathing difficulties and shortness of breath
  • Difficulty swallowing

Abdominal Aortic Aneurysm Symptoms

As with thoracic aortic aneurysms, a majority of abdominal aortic aneurysms are asymptomatic and only detected when you are screened for other conditions. This type can cause a deep, throbbing pain in the back or side of the body as well as pain in the buttocks, groin, or legs.

 Cerebral Aneurysm Symptoms

When the aneurysm occurs in arteries in the brain, symptoms only emerge when the case is more severe or there’s a rupture. In the case of unruptured cerebral aneurysms, pressure on surrounding structures can cause several signs, including:

  • Pain just above or behind the eye
  • Numbness
  • Weakness
  • Dilated pupil in one eye
  • Facial paralysis on one side
  • Vision disruption or double vision

If the artery ruptures due to the aneurysm, bleeding or subarachnoid hemorrhage will occur. In these cases, the symptoms are more severe and can be fatal. If you suspect this type, get medical help immediately. Typical signs include:

  • Very severe and sudden headache
  • Nausea and/or vomiting
  • Double vision
  • Stiff neck
  • Light sensitivity
  • Seizures (an attack of electrical activity in the brain)
  • Loss of consciousness
  • Cardiac arrest   

Peripheral Aneurysm Symptoms

As with the other types, most cases of peripheral aneurysm are asymptomatic. However, this condition can raise the risk of blood clots and cause internal bleeding if there’s a rupture or dissection. The symptoms of peripheral aneurysms include:

  • Abdominal pain
  • Loss of consciousness
  • Sudden pain, weakness, swelling, or numbness in your leg
  • Pain and discoloration in your toe(s)

What Causes an Aneurysm?

An aneurysm occurs when there is a weakening or thinning in the wall of an artery. The exact cause of aneurysms is still unknown. We do know, however, that it is possible to both be born with an aneurysm and to have one occur at any time throughout your life.

Risk Factors

A number of factors increase the risk of having an aneurysm, and these vary slightly based on type. In general, conditions and diseases that affect the health of the arteries increase the chances of developing this issue. Risk factors shared by all types of aneurysms include:

  • Smoking
  • Family or personal history of aneurysm
  • High blood pressure (hypertension)
  • Older age (over 65)
  • Genetic connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome
  • Injury

For abdominal aortic aneurysm, additional risk factors include:

  • Being assigned male at birth
  • Being Caucasian
  • High cholesterol
  • Atherosclerosis (hardened arteries)
  • Cystic medial necrosis (a disorder causing large arteries, especially the aorta)
  • Syphilis
  • Human immunodeficiency virus (HIV)

Genetic predisposition and chronic obstructive pulmonary disease (COPD) are risk factors unique to thoracic aortic aneurysms.

Lastly, the chances of developing cerebral aneurysm are higher in the following cases:

  • Drug abuse, most notably cocaine and amphetamine use
  • Age over 40
  • Polycystic kidney disease
  • Head trauma
  • Brain tumor
  • Infection of the arterial wall


As noted, aneurysms are often asymptomatic and are often detected during imaging and evaluation for other conditions. Specific diagnostic approaches vary based on the type you have. These include:

  • Physical evaluation: Palpation—essentially pushing on affected areas—may be employed to screen for abdominal and thoracic aortic aneurysms.
  • Ultrasound: This form of imaging, which relies on sound waves, is used to detect abdominal aortic aneurysms.
  • Computed tomography (CT): CT scans, a form of X-ray, can detect the location of an aortic aneurysm and may be used if a cerebral aneurysm is suspected.
  • Magnetic resonance imaging (MRI): This type of imaging, which employs magnetic waves to create two or three-dimensional images, allows providers to screen for cerebral and thoracic aortic aneurysms.
  • Magnetic resonance angiography (MRA): MRA relies on magnetic waves to create detailed, three-dimensional images of arteries around the brain, which can help detect and assess brain aneurysms.
  • Echocardiography: This type of imaging relies on sound waves to diagnose and assess the severity of a thoracic aortic aneurysm.  
  • Cerebral angiography: A means of diagnosing cerebral aneurysm, cerebral angiography relies on a contrast dye and X-ray to assess the health of artery walls.
  • Cerebrospinal fluid (CSF) analysis: This is a laboratory analysis of a sample of cerebrospinal fluid, which surrounds the brain and spine, to detect bleeding in the brain due to a cerebral aneurysm.

Treatments for Aneurysm 

Treatment approaches to aneurysm vary and are determined both by the location of the issue and its severity. Milder cases in absence of other health factors may not require any immediate therapy, though they’re monitored regularly. However, medications can work to minimize or prevent symptoms, and there are surgeries for critical cases.

Prescription Medications

You may need to try several classes of prescription medications before finding one that helps you. The goal of these medications is to manage blood pressure, which will help reduce the severity of symptoms and treat potential seizures. These medications include:

  • Calcium-channel blockers, such as Calan SR or Veralan (which are both verapamil)
  • Angiotensin receptor blockers, including Edarbi (azilsartan) and Avapro (irbesartan)
  • Anticonvulsants, such as Keppra (levetiracetam), Dilantin (phenytoin), Phenytek (phenytoin), and Valproic (sodium valproate)
  • Angiotensin-converting enzyme (ACE) inhibitors, including Lotensin (benazepril) and Capoten (captopril)
  • Statins, such as Lipitor (atorvastatin) and Lescol (fluvastatin)
  • Beta-blockers, including Inderal (propranolol) and Lopressor (metoprolol)


Because of the risk of complications, surgeries aren’t the first line of treatment for aneurysms. However, they directly take on the issue at its core. Procedures employed include:

  • Open surgical repair: In cases of abdominal and thoracic aortic aneurysms that have caused rupture or dissection, open surgery to repair or replace parts of the aorta is performed.
  • Endovascular repair: An alternative to open surgery, this less-invasive surgery involves inserting a stent—a specialized piece of mesh—through the groin. This stent is guided to the site of the aneurysm, and it reinforces the artery walls in abdominal aortic aneurysm cases.
  • Flow diversion: Stents can also be used to treat a cerebral aneurysm. Like endovascular repair, the stent is run to the problem site via the groin, using a flexible tube (endoscope). These divert blood flow from the aneurysm.
  • Shunt placement: This surgery involves placing a shunt—a small tube—to drain and divert cerebrospinal fluid, easing pressure on the brain due to a cerebral aneurysm.
  • Endovascular therapy: This is an endoscopic procedure considered when open surgery is too risky. A specialized tube is inserted via an incision near the hips to place a graft in the problem area. This then expands to support the artery walls.
  • Microvascular clipping: Used to treat cerebral aneurysms, this open brain surgery involves placing a specialized, small clip at the site of the aneurysm. This cuts off blood flow to stop the problem.
  • Platinum coil embolization: A minimally-invasive surgery for cerebral aneurysm, a catheter (a type of tube) is run to the problem area. It then deposits small coils, which reduce blood flow.

Rehabilitative Therapies

Cerebral aneurysms that have caused brain hemorrhage may cause permanent effects on motor, cognitive, and speech function. Occupational or physical therapy may be needed to address these complications.


The primary means of preventing an aneurysm is to promote the health of your heart and arteries. Several strategies can help, including:

  • Regular monitoring: If your healthcare provider has detected an unruptured aneurysm, regular medical monitoring helps to ensure issues are detected before they become dangerous.
  • Controlling high blood pressure: Since high blood pressure is a consistent risk factor for aneurysms and can make them worse, taking medications and making lifestyle adjustments to control it can help.
  • Quitting smoking: Smoking cessation and stopping the use of other tobacco products is frequently recommended if you’re at risk for or have had an aneurysm.  
  • Adjusting diet: Emphasizing fresh vegetables and fruits, lean proteins, and whole grains—and limiting saturated and trans fats and salt—are some dietary means of promoting heart health.
  • Regular exercise: Incorporate regular physical activity and exercise, aiming for at least 150 minutes a week.
  • Stopping the use of drugs: Steer clear of illicit drugs, especially cocaine and amphetamines, to help prevent cerebral aneurysms.

Comorbid Conditions   

The risk of several conditions increases if you have aneurysm. These include:

  • Chronic obstructive pulmonary disease (COPD): COPD is a group of diseases that affect breathing function. About 44% of those with abdominal aortic aneurysm develop this condition.
  • Coronary artery disease (CAD): This is characterized as a narrowing of the arteries of the heart. CAD frequently accompanies aortic aneurysms. These conditions share risk factors, and myocardial infarction (heart attack) and heart failure are also related.
  • Peripheral artery disease (PAD): A narrowing of arteries outside of the heart—often in the limbs—is another comorbid condition. This, too, shares risk factors.
  • Stroke: Cerebral aneurysms that rupture and cause bleeding (subarachnoid hemorrhage) can cause stroke, in which parts of the brain die because they don’t get the blood they need.
  • Gallstones: Gallstones occur when calcified deposits of digestive juices form in the gallbladder. Researchers have found that 12% of abdominal aortic aneurysm patients also had gallstones.
  • Diverticulosis: This is the development of small pouches within the lining of the digestive tract. In a 2019 study of 100 patients, half of abdominal aortic aneurysm patients had diverticulosis.

Living With an Aneurysm

While most aneurysms are asymptomatic, the condition can become very dangerous if arteries burst. The good news is that artery rupture is relatively rare; only 0.25% of aneurysms cause this condition. Not only that, adequate screening and preventive management greatly improve outcomes.  

You can live a long time with various aneurysm types, so preventing the worsening of symptoms is key. Managing your blood pressure by regularly exercising, not smoking, eating a balanced diet, and limiting your alcohol consumption can not only extend your life, but improve your quality of life along the way.

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10 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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