Aneurysms can happen to anyone at any age, and most of the time, they have no symptoms or warning signs. Most people would agree that’s a scary possibility. But the fact is knowing the causes of aneurysms can help you prevent them and get prompt treatment should one affect you in the future.
“An aneurysm is some sort of bulging of a blood vessel within the body,” says George P. Teitelbaum, MD, medical director of the Providence Neurovascular Center in Santa Monica, California.
Arteries are a type of blood vessel that carry oxygen-rich blood from the heart to other parts of the body. The thick walls of the arteries are meant to hold up under normal blood pressure, but when the walls weaken or become damaged, an aneurysm can develop.
Aneurysms have two shapes: (1)
Saccular Aneurysm The most common type, this is also known as the “berry” aneurysm because of the berry-like sac that develops on the “y” section of the artery, as well as the neck and stem that forms.
Fusiform Aneurysm This type of aneurysm is less common and has an equal “outpouching” of the artery wall on all sides without a stem. It’s also the type of aneurysm that has a lower risk of rupture.
Types of Aneurysms
An aneurysm can occur in any blood vessel in the body, but those that occur in the brain, chest, and abdomen are the most serious, says Kimberly Brown, MD, MPH, an emergency care physician based in Memphis, Tennessee.
Abdominal Aortic Aneurysms
The aorta is the main artery in the body that supplies oxygen to the brain, muscles, and cells in the body. An abdominal aortic aneurysm develops in the portion of the aorta located in the abdomen. Abdominal aortic aneurysms affect 4 to 8 percent of people. (2)
Thoracic Aortic Aneurysms
A thoracic aortic aneurysm forms in the portion of the aorta in the chest above the diaphragm. Only 50 percent of people who develop a thoracic aortic aneurysm notice symptoms. (3)
Thoracic aortic aneurysms occur in about 10 in 100,000 people. (4)
A cerebral aneurysm is in the arteries of the brain. Sometimes, these aneurysms are called brain or intracranial aneurysms.
About 30,000 people a year will be affected by ruptured cerebral aneurysms, and most are between ages 30 and 60. (5)
Peripheral aneurysms affect areas of the body other than the aorta or the brain.
These aneurysms can occur in the popliteal artery located behind the knees, the femoral arteries, or the main arteries in the groin and the carotid arteries in the neck. (6)
Peripheral aneurysms in the abdomen, also known as splenic aneurysms, are rare and affect 0.7 percent of the population. (7) Those in the legs are also uncommon and affect 0.007 percent of men and fewer women.
About 70 percent of peripheral arterial aneurysms are popliteal aneurysms, and 20 percent are iliofemoral aneurysms, located in the hip joint. These types of aneurysm are usually accompanied by abdominal aortic aneurysms, and more than 50 percent occur on both sides. (8)
Mycotic and Dissecting Aneurysms
Mycotic and dissecting aneurysms are disease processes by which aneurysms can form, rather than individual types of aneurysm. For example, someone can be diagnosed with a mycotic cerebral aneurysm or a dissecting carotid aneurysm, which affects the carotid artery that carries blood to the head and brain. (9)
Mycotic Aneurysm Mycotic aneurysms are caused by a bacterial infection, usually one that originated in the heart, such as endocarditis, and cause the arterial wall to become infected and dilate. (10)
Mycotic aneurysms are rare and represent 0.6 percent of all aortic aneurysms. (11)
Dissecting Aneurysm An aneurysm can also grow and dissect in both the brain and the aorta. “Blood dissects or travels underneath a tear in the innermost layer called the intima,” Dr. Teitelbaum says. “It lifts up the intima and causes a ‘bleb,’ or an aneurysmal outpouching of the blood vessel,” he says.
Aortic dissection is uncommon and occurs in 5 to 30 cases per one million people each year. (12)
Learn More About Types of Aneurysms
Signs and Symptoms of Aneurysms
Here’s a detailed look at the potential signs of an aneurysm by type: (1,13)
Abdominal Aortic Aneurysms
- Sudden-onset abdominal pain
- Blood in the urine or stool
- Abdominal bloating
Thoracic Aortic Aneurysms
- Sudden onset, severe, “ripping” chest pain
- Shortness of breath
- Hoarseness or difficulty swallowing
- Double vision
- Vision loss
- Dilated pupils
- Sudden onset headache
- Pain above and behind the eye
- Eyelid drooping
- Weakness, numbness
- Difficulty speaking
- Pulsing sound in one ear
- Abdominal pain
- Sudden pain, weakness, swelling, and numbness in the leg
- Painful, discolored toe (7)
- Weight loss
- Severe headache
- Altered mental status
- Painful mass in an extremity (14)
- Upper back pain
- Sudden loss of vision (15)
Learn More About Signs and Symptoms of an Aneurysm
Causes and Risk Factors of an Aneurysm
Aneurysms occur as a result of the blood pushing against the wall of the arteries, along with damage or an injury to the artery’s walls. Various factors may drive their development.
In addition to certain health conditions, risk factors for an aneurysm include having:
- Poor diet
- Substance abuse disorder, especially of drugs that spike blood pressure
- Being 55 or older
- History of physical trauma
Genetics also affect aneurysm risk. For example, those who have a close relative with an abdominal aortic aneurysm are 12 to 15 times more likely to be affected themselves, Teitelbaum says.
The most common cause of cerebral aneurysms is a congenital weak spot that balloons out over time. In this case, it’s important to get screened, Teitelbaum says.
Because an aneurysm can occur without warning, it’s important to consider your individual risk factors and make lifestyle changes to areas you can control.
Why Are Aneurysms More Prevalent Among Women Compared With Men?
Although men are 4 to 6 times more likely than women to have abdominal aortic aneurysms, women have a higher risk of these aneurysms rupturing, regardless of the aneurysm size. (16)
Women are also slightly more likely than men to have brain aneurysms, at a ratio of 3:2. (17)
It’s not entirely clear why women have an increased risk of certain aneurysm events, but it could be because their symptoms (like a dull, persistent headache or vague abdominal pain) are atypical, making it harder to diagnose, says Dr. Brown.
There may also be genetic factors that increase the likelihood for women to have weakened blood vessel layers, Teitelbaum says.
Learn More About Causes of Aneurysms: Common Risk Factors, Genetics and More
The Link Between Smoking and Aneurysms
Smoking cigarettes is a risk factor for all types of aneurysms. Smoking can also increase the risk of recurrence after an aneurysm has been treated.
A study found that of a group of people who had been treated with endovascular aneurysm repair (EVAR), former and current smokers had a recurrence rate of 23.6 percent, and those who never smoked had a recurrence rate of 17.2 percent. (18) EVAR is a minimally invasive alternative to open-repair surgery, in which platinum coils or a stent are inserted into an aneurysm to prevent blood flow and rupture.
Smoking destroys the walls of the arteries and breaks down the lining. Over time, the body tries to repair itself by building up plaque and forming clots, which make them more prone to ballooning. “Anything that spikes your blood pressure can weaken that wall and cause things to leak and to rupture,” says Brown. People who quit smoking still have an elevated risk, but “the longer that you’re smoke-free, the better,” she says.
Smoking, combined with genetics, can also increase the risk for aneurysm. Having a plan and knowing where to turn for support are two keys quitting smoking.
Learn More About How Smoking Can Increase Your Risk of an Aneurysm
How Is an Aneurysm Diagnosed?
Along with symptoms, several screening and diagnostic tools are used by doctors to diagnose an aneurysm.
For abdominal and thoracic aortic aneurysms, a computerized tomography (CT) angiogram can help doctors see the extent of the aneurysm and if there is also clot in it, Teitelbaum says.
Magnetic resonance imaging (MRI) may also be used.
An abdominal ultrasound is recommended to screen men for aortic aneurysms. If an aneurysm smaller than 5.5 centimeters (cm) in diameter is found, your doctor will repeat the ultrasound every 6 to 12 months to make sure it doesn’t grow. Abdominal aortic aneurysms are the easiest to detect and follow, Brown says.
Because symptoms can be vague and look different in women than in men, it’s important to know all the warning signs to look for.
In 2019, the U.S. Preventive Services Task Force also updated their screening guidelines for abdominal aortic aneurysm for people who do not have signs or symptoms. (19) According to the new recommendations, men between the ages of 65 to 75 who have ever smoked should have a one-time ultrasound screening instead of routine screening of all men in the age group. Furthermore, the task force recommends against routine screening for abdominal aortic aneurysm in women who have never smoked and have no family history of the condition.
Symptoms of a cerebral aneurysm can help your doctor make a diagnosis, but not everyone will have symptoms. “About 2 to 5 percent of Americans are walking around right now with a brain aneurysm, and most don’t know it, since most of the time the first sign of an aneurysm is when it ruptures,” Teitelbaum says.
A CT scan uses X-ray images to detect a cerebral aneurysm. But if the scans don’t detect anything, your doctor may use angiography, a test that uses dyes and X-rays to better visualize blood vessels and arteries, Teitelbaum says.
Aneurysms that slightly bleed, known as sentinel hemorrhage, may not be detected on a CT scan, and in this case, a spinal tap will be done, Teitelbaum says.
Peripheral aneurysms are diagnosed in physical exams. If one is suspected, duplex ultrasound and computerized tomography (CT) scans will be ordered to confirm the diagnosis. (7)
Mycotic aneurysms can be diagnosed based on four different criteria: symptoms, laboratory results, CT or MRI results, or findings during surgery. But there is not yet a full consensus on how to diagnose them. (11)
A dissecting aneurysm is diagnosed with a chest X-ray, however 10 to 20 percent of patients with a dissecting aneurysm have a normal X-ray. Other tests, such as MRI, CT scan, and transesophageal echocardiography (TEE), may be used. (20)
The outcomes and chance of recovery for aneurysm depend on the type.
Abdominal Aortic Aneurysms
Abdominal aortic aneurysms of 3 to 4 cm in diameter are considered small, 4 to 5.5 cm are considered medium, and greater than 5.5 cm are considered large. Risk of aneurysm rupture increases markedly at aneurysm diameters greater than 5.5 cm. (21)
About 50 percent of those with a ruptured abdominal aortic aneurysm make it to the hospital alive. Of those who do, up to 50 percent do not survive the repair. (22) Meanwhile, those who have an elective operation have between 1 and 5 percent risk. (23) “Since there is that death rate of elective treatment of abdominal aortic aneurysms, that’s why surgeons want to wait until they’re definitely in the range of a higher risk of rupture,” Teitelbaum says.
In 2014, aortic aneurysms in general were the primary cause of nearly 10,000 deaths, while in 2009, they were a contributing cause of 17,215 deaths in the United States. (24,25)
Overall, abdominal aortic aneurysms are estimated to cause 4 to 5 percent of sudden deaths. (26)
Thoracic Aortic Aneurysms
The risk of rupture is directly correlated to the diameter of a thoracic aortic aneurysm. (27)
According to a 2015 study, people with aortic diameters of 50, 55, and 60 mm had an aortic event within one year at a rate of 5.5 percent, 7.2 percent, and 9.3 percent, respectively. (28)
Overall, between 50 and 80 percent of people who suffer a thoracic aortic rupture do not survive. (29)
Among patients with a thoracic aortic aneurysm who have elective surgery, the five-year survival rate is 85 percent, while those who undergo emergency surgery have a five-year survival rate of 37 percent. (30)
Cerebral aneurysms that are less than 10 millimeters (mm) in diameter are considered small, those between 10 and 25 mm are large, and those that are greater than 25 mm are “giant.” “These are the aneurysms that do the worst. They tend to recur, and they cause the greatest number of deaths,” Teitelbaum says.
About 25 percent of people who have a ruptured cerebral aneurysm do not survive the first 24 hours. Another 25 percent die from complications within six months. (5) Overall, about 40 percent of cases of brain aneurysms that rupture are fatal. (17)
In recent years, however, the prognosis among people with unruptured cerebral aneurysms has improved. (31)
The risk of rupture of peripheral aneurysms is low. Less than 5 percent are popliteal aneurysms, or those located in the back of the knee, and between 1 and 14 percent of iliofemoral aneurysms, located in the hip joint, are at risk of rupture. (8)
Still, blood clots can form, break away, and prevent blood flow through the artery. (3) What’s more, a large peripheral aneurysm can press on a nearby nerve or vein and cause pain, numbness, or swelling. (3)
Nearly all untreated mycotic aneurysms lead to rupture and can be fatal, which is why timely diagnosis and treatment are key. (10)
These types of aneurysms can rupture and cause bleeding, cut off the blood flow to the small vessels that come out of the main artery or to larger branches, cause stroke, and cause organ and cell damage that may be fatal (called necrosis).
Thoracic aortic aneurysms that measure less than 6 cm have between 31 and 43 percent risk of rupture depending on location. Between 2.5 and 8 percent of surgeries will be fatal. (32)
Duration of Aneurysm
Treatment and Medication Options for Aneurysm
Treatment for an aneurysm depends on its cause, size, location, the factors that put you at risk, and whether the aneurysm has ruptured or is at risk for rupture. (35) Your doctor may decide on a wait-and-watch approach, medication, surgery, or a combination of treatments.
Wait and Watch
All types of aneurysms that are small and asymptomatic may only require close and careful monitoring, with imaging studies (X-rays, ultrasound, CT scan, or MRI) performed periodically. The size and rate of growth, however, will determine how frequently it should be checked.
Blood pressure medicines, such as calcium channel blockers and beta blockers, may be prescribed to control blood pressure because hypertension can further weaken an aneurysm and increase the risk for leaking or rupture.
Statins, such as atorvastatin (Lipitor), may also be used to prevent vasospasm, a condition in which the arteries in the brain narrow after a brain aneurysm rupture.
Antiplatelet medication may also be prescribed in patients who undergo surgery to repair cerebral aneurysm. (36)
Surgery Options and Procedures
Abdominal Aortic Aneurysms and Thoracic Aortic Aneurysms For large, leaking, or ruptured aortic aneurysms, two types of treatments are available: open repair and endovascular stenting, Teitelbaum says. During open repair, the surgeon removes the aneurysm and a portion of the aorta. The section of the aorta is then replaced with a graft made from material such as Dacron or Teflon. (37)
With endovascular stenting, the surgeon threads a catheter into the aneurysm, uses an X-ray to visualize the artery, and inserts a collapsed stent into the aneurysm. The stent graft allows blood flow through the aorta instead of the aneurysm and reinforces the weakened section of the aorta to prevent a rupture.
Cerebral Aneurysm Brain aneurysms that have burst will require emergency surgery for the aneurysm itself and to evacuate blood from the skull or to drain excess fluid from the brain.
If an aneurysm is growing or at risk of rupture or dissection, there are two options for a ruptured brain aneurysm: open repair (or microvascular clipping) and endovascular embolization (or EVAR repair).
Open repair is a treatment in which a small titanium clip is placed across the neck of the aneurysm to prevent blood flow. Once the aneurysm appears to have disappeared, the odds of recurrence are very small, Teitelbaum says.
Meanwhile, endovascular embolization is a treatment in which coils are inserted into the aneurysm to stabilize it and prevent blood flow. The wire causes a blood clot and destroys the aneurysm. (38)
For large or wide aneurysms where your doctor doesn’t advise a watch-and-wait approach, flow diversion treatment will be used. The treatment uses a device made of fine metal wires that guide blood flow through the artery and past the aneurysm, resulting in closure of the aneurysm. Unlike other treatments, it’s the only one that doesn’t have the risk for recurrence, Teitelbaum says.
In July 2018, the U.S. Food and Drug Administration (FDA) approved the Surpass Streamline Flow Diverter, a stent for the treatment of wide-neck and fusiform intracranial aneurysms. (39)
Additionally, in December 2018, the FDA approved the WEB (Woven EndoBridge) Device, a self-expanding mesh ball that is meant to reduce blood flow to cerebral aneurysms. (40) The device is navigated through catheters from blood vessels in the legs into the brain. It conforms to the shape of the aneurysm and prevents blood flow and the risk of rupture. (41)
Peripheral Aneurysm The treatment for a peripheral aneurysm depends on its location, the condition of the surrounding blood vessels, and other medical issues. (7)
Bypass surgery is one option. The blood flow is redirected around the aneurysm, and then the aneurysm is removed or tied off to prevent blood from filling it up again.
A stent graft, which is placed inside the vein to seal off the aneurysm, is another type of treatment.
A splenic aneurysm may be treated with embolization of the aneurysm or by removing the spleen.
Mycotic Aneurysm Mycotic aneurysms are treated with a combination of antibiotics and open repair surgery or endovascular aneurysm repair (EVAR). (42)
Dissecting Aneurysm Beta-blockers may be prescribed to lower blood pressure and heart rate to a normal range. (12) In some patients, surgery may be performed to prevent aortic rupture and other issues with the heart.
Treatment for an aneurysm is individual and based on several factors. Because all types of surgery carry risks, and recovery times vary, it’s important to compare the options with your doctor.
Onyx A liquid embolic agent, Onyx is an FDA-approved treatment for intracranial, saccular, sidewall aneurysms that have a wide neck. (43) Onyx is a liquid polymer that is injected through a microcatheter into the aneurysm. The substance solidifies, sealing off blood flow to the aneurysm in order to reduce pressure and risk of rupture. (44) The treatment is used in place of, or in combination with, endovascular embolization with coils.
Learn More About Treatment for Aneurysm: Medication, Alternative and Complementary Therapies, Surgery Options and More
Prevention of Aneurysm
Because aneurysms can cause lifelong health complications or be fatal, it’s important to know the risk factors and your family history. “Make sure you have a family doctor that you trust that really knows you and knows your family history and can monitor your symptoms if you start having headaches, chest pain, or abdominal pain,” Brown says.
Additionally, there are certain diet and lifestyle changes you can make to prevent an aneurysm.
Avoid foods high in calories, saturated fat, trans fat, and sodium when you can. Instead, focus on whole foods, including plenty of fruits and vegetables, lean protein such as boneless and skinless chicken breast, whole grains, and healthy fats like avocado and nut butter. If you have high cholesterol, eat foods rich in omega-3 fatty acids like fatty fish, nuts, and seeds to help get your levels in a healthy range. (45)
If you have high blood pressure, work with your doctor to manage it.
Use an at-home blood pressure monitor every day, eat a low-sodium diet, maintain your weight, exercise regularly, and find ways to reduce stress. (46)
A regular fitness regimen can lower your blood pressure and triglycerides, raise good cholesterol, and, in combination with a healthy diet, help you lose weight. (47) But if you have been diagnosed with an aneurysm, it’s important to work with your doctor on finding low-impact workouts.
Studies show smoking significantly increases your chances of aneurysm. According to a 2018 study, women between 30 and 60 years old who were smokers had a fourfold increased risk for an unruptured intracranial aneurysm. (48)
Over-the-counter smoking cessation aids, prescription medication, and support groups can all help you kick the habit. Talk to your doctor about which options he or she thinks would work best for you.
Seek Treatment for Depression
While studies suggest depression is associated with cardiovascular disease, less is known about aneurysm risk among people with this mental illness. Yet according to a 2019 study, individuals with symptoms of depression have a 30 percent increased risk of abdominal aortic aneurysms. (49)
If you have symptoms of depression, it’s important to talk with your doctor about lifestyle changes and treatment options.
Learn More About How to Help Prevent Aneurysms
Complications of Aneurysm
The complications of an aneurysm depend on the type, severity, and if the aneurysm has ruptured.
Abdominal Aortic and Thoracic Aortic Aneurysm
Complications of aortic aneurysms include aortic dissection, regurgitation, insufficiency, rupture, heart failure, cardiac tamponade, kidney failure, lack of blood flow to the bowels, and injury to the large intestine. (3)
People who experience a ruptured abdominal aortic aneurysm typically have shooting abdominal or back pain and severe low blood pressure. (50)
A ruptured cerebral aneurysm can cause repeat bleeding, change in sodium levels and swelling, hydrocephalus, stroke, seizures, and permanent brain damage. (5)
Complications of a peripheral aneurysm are rare but may include rupture and thromboembolism, a blood clot that starts in the vein. (21)
Mycotic aneurysms are associated with mortality rates due to subarachnoid and intracerebral hemorrhage. (51)
Complications of dissecting aneurysms include multi-organ failure, stroke, myocardial infarction, renal failure, paralysis, lack of blood flow to the bowels, cardiac tamponade, acute aortic regurgitation, compression of the superior vena cava, and death. (12)
Research and Statistics: How Many People Have an Aneurysm Each Year?
About 6.5 million people in the United States, or 1 in 50, have an unruptured brain aneurysm each year, while 30,000 people in the United States experience a brain aneurysm rupture each year. (1)
The prevalence of abdominal aortic aneurysm in the United States for the overall population is about 2.2 percent, and between 4 and 7 percent of men over the age of 65 are affected. (52)
About 6 to 10 per every 100,000 people experience thoracic aortic aneurysms, and about 20 percent of those cases are linked to family history. (13)
BIPOC Communities and Aneurysm
Certain communities have a higher risk for various types of aneurysm.
Black, Hispanic, and Asian Americans have been found to have lower rates of abdominal aortic aneurysm than white and Native Americans. (53)
Compared with white Americans, Black Americans and Hispanics are almost twice as likely to have a brain aneurysm rupture. (1)
While the prevalence of abdominal aortic aneurysm is more common in white Americans than Black Americans, the latter have been found to have worse outcomes after repair. (54)
A past study found Hispanic patients who underwent repair for abdominal aortic aneurysm had more comorbidities, more frequently had ruptured aneurysms, and had higher 30-day mortality rates. (55)
Related Conditions and Causes of Aneurysm
There are certain conditions associated with elevated aneurysm risk. They include:
- High blood pressure (hypertension)
- High cholesterol
- Bacterial infections
- Certain genetic conditions, such as moyamoya disease, fibromuscular dysplasia, Marfan syndrome, Ehlers-Danlos syndrome, and neurofibromatosis
Resources We Love
Favorite Orgs for Essential Aneurysm Info
National Heart, Lung, and Blood Institute
An aneurysm is a complex and often confusing condition, so having a resource on hand that makes it easier to understand can be a game changer. We particularly appreciate this resource from the National Heart, Lung, and Blood Institute for its discussion on the basics you need to know about aortic aneurysm causes, risk factors, symptoms, treatment options, and more.
For a more succinct breakdown on aneurysms, check out this overview page from the American Heart Association. Here you can learn about the different types and symptoms of aneurysm. Bonus: You’ll even learn how to help reduce your risk of aneurysm, which may be especially important if this condition runs in your family, or if you’ve had a history of lifestyle habits that might otherwise increase your risk of developing an aneurysm.
Favorite Aneurysm Support Networks
If an aneurysm has affected you or a loved one, we recommend checking out this support group from the renowned Mayo Clinic. Located at the Mayo Clinic’s St. Mary’s campus in Rochester, Minnesota, the group meets during the evenings on the first Thursday of every month, and a registered nurse facilitates discussions. If you’re nowhere near Rochester, why not check out this resource for inspiration on starting an aneurysm support group in your hometown?
While mental health professionals generally recommend in-person support groups, such get-togethers may not be convenient for you. This is where online support groups like this one from the Brain Aneurysm Foundation can be helpful. You can even post a blog about your experiences on the community website as a way to cope and inspire others.
Favorite Sites for Aneurysm Diet Advice
American College of Cardiology
Your doctor may have told you that it’s important to reduce your blood pressure to prevent an aneurysm from getting worse. But where do you start? Aside from stress management, your diet can play a key role in reducing your blood pressure, and this resource from the American College of Cardiology provides a few tips on how to get started.
The DASH (Dietary Approaches to Stop Hypertension) diet is one way you can help support your health while dealing with an aneurysm. The Mayo Clinic outlines the DASH diet in this handy resource on dietary tips for hypertension. We recommend bookmarking this resource for diet and other tips, such as stress management strategies and exercise ideas.
Favorite Aneurysm Conferences
Researchers are actively studying aneurysms to improve how they’re diagnosed, managed, and treated. For some of the latest info on aneurysm studies, check out this resource’s conference. If you can’t attend the next meeting, download and print a copy of the conference agenda to take to your next doctor’s appointment or support group session.
Favorite Clinical Trial Outreach
You may be interested in furthering related research rather than just reading about it. In that case, you may consider participating in a clinical trial. Bookmark this resource from the National Institutes of Health to be on the lookout for clinical trials in your area, and if you spot one you’re interested in joining, be sure to chat with your healthcare team first.
Likewise, if you’re on the hunt for clinical trials related to brain aneurysms only, take a look at this page from the Brain Aneurysm Foundation. The overall focus of most of the listed clinical trials is related to genes and how certain markers may contribute to the formation of brain aneurysms.
Additional reporting by Rosalyn Carson-DeWitt, MD, and Beth W. Orenstein.