Aneurysm

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An aneurysm is an abnormal bulge or "ballooning" in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body. An aneurysm that grows and becomes large enough can burst, causing dangerous, often fatal, bleeding inside the body.

Most aneurysms occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body. The aorta comes out from the left ventricle of the heart and travels through the chest and abdomen. An aneurysm that occurs in the aorta in the chest is called a thoracic aortic aneurysm. An aneurysm that occurs in the aorta in the abdomen is called an abdominal aortic aneurysm.

Aneurysms also can occur in arteries in the brain, heart, intestine, neck, spleen, back of the knees and thighs, and in other parts of the body. If an aneurysm in the brain bursts, it causes a stroke.

About 15,000 Americans die each year from ruptured aortic aneurysms. Ruptured aortic aneurysm is the 10th leading cause of death in men over age 50 in the United States.

Many cases of ruptured aneurysm can be prevented with early diagnosis and medical treatment. Because aneurysms can develop and become large before causing any symptoms, it is important to look for them in people who are at the highest risk. Experts recommend that men who are 65 to 75 years old and have ever smoked (at least 100 cigarettes in their lifetime) should be checked for abdominal aortic aneurysms.

When found in time, aneurysms can usually be treated successfully with medicines or surgery. If an aortic aneurysm is found, the doctor may prescribe medicine to reduce the heart rate and blood pressure. This can reduce the risk of rupture.

Large aortic aneurysms, if found in time, can often be repaired with surgery to replace the diseased portion of the aorta. The outlook is usually excellent.

 

Types

Types of aneurysm include aortic aneurysms, cerebral aneurysms, and peripheral aneurysms.

Aortic Aneurysm

Most aneurysms occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body. The aorta comes out from the left ventricle of the heart and travels through the chest and abdomen. The two types of aortic aneurysm are thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA).

Thoracic Aortic Aneurysm

An aortic aneurysm that occurs in the part of the aorta running through the thorax (chest) is a thoracic aortic aneurysm. One in four aortic aneurysms is a TAA.

Most TAAs do not produce symptoms, even when they are large. Only half of all people with TAAs notice any symptoms. TAAs are identified more often now than in the past because of chest computed tomography (CT) scans performed for other medical problems.

In a common type of TAA, the walls of the aorta become weak and a section nearest to the heart enlarges. Then the valve between the heart and the aorta cannot close properly and blood leaks backward into the heart. Less commonly, a TAA can develop in the upper back away from the heart. A TAA in this location can result from and injury to the chest such as from an auto crash.

Abdominal Aortic Aneurysm

An aortic aneurysm that occurs in the part of the aorta running through the abdomen is an abdominal aortic aneurysm. Three in four aortic aneurysms are AAAs.

An AAA can grow very large without producing symptoms. About 1 in 5 AAAs rupture.

Figure A shows a normal aorta. Figure B shows a thoracic aortic aneurysm located behind the heart. Figure C shows an abdominal aortic aneurysm located below the arteries that supply the kidneys.

Cerebral Aneurysm

Aneurysms that occur in an artery in the brain are called cerebral aneurysms. They are sometimes called berry aneurysms because they are often the size of a small berry. Most cerebral aneurysms produce no symptoms until they become large, begin to leak blood, or rupture.

The illustration shows a typical location of a cerebral (berry) aneurysm in the arteries supplying blood to the brain. The inset image shows a closeup of the sac-like aneurysm.

A ruptured cerebral aneurysm causes a stroke. Signs and symptoms can include a sudden, extremely severe headache, nausea, vomiting, stiff neck, sudden weakness in an area of the body, sudden difficulty speaking, and even loss of consciousness, coma, or death. The danger of a cerebral aneurysm depends on its size and location in the brain, whether it leaks or ruptures, and the person’s age and overall health.

Peripheral Aneurysm

Aneurysms that occur in arteries other than the aorta (and not in the brain) are called peripheral aneurysms. Common locations for peripheral aneurysms include the artery that runs down the back of the thigh behind the knee (popliteal artery), the main artery in the groin (femoral artery), and the main artery in the neck (carotid artery).

Peripheral aneurysms are not as likely to rupture as aortic aneurysms, but blood clots can form in peripheral aneurysms. If a blood clot breaks away from the aneurysm, it can block blood flow through the artery. If a peripheral aneurysm is large, it can press on a nearby nerve or vein and cause pain, numbness, or swelling.

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Symptoms

The signs and symptoms of an aneurysm depend on its type, location, and whether it has ruptured or is interfering with other structures in the body. Aneurysms can develop and grow for years without causing any signs or symptoms. It is often not until an aneurysm ruptures or grows large enough to press on nearby parts of the body or block blood flow that it produces any signs or symptoms.

Abdominal Aortic Aneurysm

Most abdominal aortic aneurysms (AAAs) develop slowly over years and have no signs or symptoms until (or if) they rupture. Sometimes, a doctor can feel a pulsating mass while examining a patient's abdomen. When symptoms are present, they can include:

• Deep penetrating pain in your back or the side of your abdomen
• Steady gnawing pain in your abdomen that lasts for hours or days at a time
• Coldness, numbness, or tingling in your feet due to blocked blood flow in your legs

If an AAA ruptures, symptoms can include sudden, severe pain in your lower abdomen and back; nausea and vomiting; clammy, sweaty skin; lightheadedness; and a rapid heart rate when standing up. Internal bleeding from a ruptured AAA can send you into shock. Shock is a life-threatening condition in which the organs of the body do not get enough blood flow.

Thoracic Aortic Aneurysm

A thoracic (chest) aortic aneurysm may have no symptoms until the aneurysm begins to leak or grow. Signs or symptoms may include:

• Pain in your jaw, neck, upper back (or other part of your back), or chest
• Coughing, hoarseness, or trouble breathing

Cerebral Aneurysm

If a cerebral (brain) aneurysm presses on nerves in your brain, it can cause signs and symptoms. These can include:

• A droopy eyelid
• Double vision or other changes in vision
• Pain above or behind the eye
• A dilated pupil
• Numbness or weakness on one side of the face or body

If a cerebral aneurysm ruptures, symptoms can include a sudden, severe headache, nausea and vomiting, stiff neck, loss of consciousness, and signs of a stroke. Signs of a stroke are similar to those listed above for cerebral aneurysm, but they usually come on suddenly and are more severe. Any of these symptoms require immediate medical attention.

Peripheral Aneurysm

Signs and symptoms of peripheral aneurysm may include:

• A pulsating lump that can be felt in your neck, arm, or leg
• Leg or arm pain, or cramping with exercise
• Painful sores on toes or fingers
• Gangrene (tissue death) from severely blocked blood flow in your limbs

An aneurysm in the popliteal artery (behind the knee) can compress nerves and cause pain, weakness, and numbness in your knee and leg.

Blood clots can form in peripheral aneurysms. If a clot breaks loose and travels through the bloodstream, it can lodge in your arm, leg, or brain and block the artery. An aneurysm in your neck can block the artery to the brain and cause a stroke.

Diagnosis

An aneurysm may be found by chance during a routine physical exam. More often, an aneurysm is found by chance during an x ray, ultrasound, or computed tomography (CT) scan performed for another reason, such as chest or abdominal pain.

If you have an abdominal aortic aneurysm (AAA), the doctor may feel a pulsating mass in your abdomen. A rapidly growing aneurysm about to rupture can be tender and very painful when pressed. If you are overweight or obese, it may be difficult for your doctor to feel even a large abdominal aneurysm.

If you have an AAA, your doctor may hear rushing blood flow instead of the normal whooshing sound when listening to your abdomen with a stethoscope.

Diagnostic Tests and Procedures

To diagnose and eval‎uate an aneurysm, one or more of the following tests or procedures may be performed:

• Chest x ray. A chest x ray provides a picture of the organs and structures inside the chest, including the heart, lungs, and blood vessels.
• Ultrasound. This simple and painless test uses sound waves to create a picture of the inside of the body. It shows the size of an aneurysm, if one is detected. The ultrasound scan may be repeated every few months to see how quickly an aneurysm is growing.
• CT scan. A CT scan provides computer-generated, x-ray images of the internal organs. A CT scan may be performed if the doctor suspects a TAA or AAA. A liquid dye that can be seen on an x ray is injected into an arm vein to outline the aorta or artery on the CT scan. The CT scan images can be used to determine the size and shape of an abdominal aneurysm more accurately than an ultrasound.
• MRI. MRI uses magnets and radio waves to create images of the inside of the body. It is very accurate in detecting aneurysms and determining their size and exact location.
• Angiography. Angiography also uses a special dye injected into the blood stream to make the insides of arteries show up on x-ray pictures. An angiogram shows the amount of damage and blockage in blood vessels.
• Aortogram. An aortogram is an angiogram of the aorta. It may show the location and size of an aortic aneurysm, and the arteries of the aorta that are involved.

Causes

An aneurysm can result from atherosclerosis (hardening and narrowing of the inside of arteries). As atherosclerosis develops, the artery walls become thick and damaged and lose their normal inner lining. This damaged area of artery can stretch or “balloon" from the pressure of blood flow inside the artery, resulting in an aneurysm.

An aneurysm also can develop from constant high blood pressure inside an artery.

A thoracic aortic aneurysm can result from an injury to the chest (for example, an injury that occurs from an auto crash). Certain medical conditions, such as Marfan syndrome, that weaken the body’s connective tissues, also can cause aneurysms.

In rare cases, infections such as untreated syphilis (a sexually transmitted infection) can cause aortic aneurysms. Aortic aneurysms also can occur as a result of diseases that cause inflammation of blood vessels, such as vasculitis.

Reference:

National Heart, Lung, and Blood Institute, USA.