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 large enough can burst, causing dangerous, often fatal, bleeding inside the body.

Most aneurysms occur in the aorta, but they can also occur in other arteries in the brain, heart, intestine, neck, spleen, back of the knees and thighs, or elsewhere in the body. If an aneurysm in the brain bursts, it can cause a stroke.

Many cases of ruptured (burst) aneurysm can be prevented with early diagnosis and medical treatment. Because aneurysms can grow large before causing symptoms, it is important to look for them in people who are at the highest risk.

When found in time, aneurysms can usually be treated successfully with medicines or surgery.


Contents<

  • 1 Types
    o 1.1 Aortic aneurysm
    + 1.1.1 Thoracic aortic aneurysm
    + 1.1.2 Abdominal aortic aneurysm
    o 1.2 Cerebral aneurysm
    o 1.3 Peripheral aneurysm
    * 2 Signs and Symptoms
    o 2.1 Thoracic aortic aneurysm
    o 2.2 Abdominal aortic aneurysm
    o 2.3 Cerebral aneurysm
    o 2.4 Peripheral aneurysm
    * 3 Causes
    * 4 Diagnosis
    o 4.1 Exams and tests
    o 4.2 Specialists
    * 5 Treatment
    o 5.1 Aortic aneurysm
    + 5.1.1 Open repair
    + 5.1.2 Endovascular repair
    o 5.2 Cerebral aneurysm
    o 5.3 Peripheral aneurysm
    * 6 Prevention
    * 7 Chances of Developing an Aneurysm
    o 7.1 Risk factors
    * 8 Clinical Trials
    * 9 References
    * 10 External Links

Types

Types of aneurysm include thoracic and abdominal aortic aneurysms, cerebral aneurysms, and peripheral aneurysms.
Typical location of a cerebral (berry) aneurysm in the arteries supplying blood to the brain. Inset shows a closeup of the sac-like aneurysm. Source: NHLBI
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 (main pumping area) 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.
Thoracic aortic aneurysm

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

Many 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 an injury to the chest such as from a car crash.
Abdominal aortic aneurysm

An aortic aneurysm that occurs in the part of the aorta running through the abdomen is called an abdominal aortic aneurysm (AAA, pronounced triple A by many clinicians). Three out of four aortic aneurysms are AAAs.

An AAA can grow very large without producing symptoms, so a person can have one without even knowing it. About one in five AAAs rupture (burst open).
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.

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.

Sometimes a cerebral aneurysm will leak a small amount in what is called a sentinel bleed. This causes a bad headache that gets better, followed a few days later by the true rupture.
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 popliteal artery that runs down the back of the thigh behind the knee; the femoral artery, which is the main artery in the groin; and the carotid artery, which is the main artery in the neck.

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 travel to another part of the artery and block blood flow through the artery. If a peripheral aneurysm is large, it can press on a nearby nerve or vein causing pain, numbness, or swelling.
Signs and Symptoms

The symptoms of an aneurysm depend on its type, location, and whether it has ruptured or is interfering with other structures in the body. 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 symptoms.
Thoracic aortic aneurysm

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

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

Abdominal aortic aneurysm

Most abdominal aortic aneurysms (AAAs) develop slowly over years and have no 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 the back or the side of the abdomen
    * Steady gnawing pain in the abdomen that lasts for hours or days at a time
    * Coldness, numbness, or tingling in the feet due to blocked blood flow in the legs

The pain from a ruptured AAA can sometimes be confused with the pain of a kidney stone.

If an AAA ruptures, symptoms can include sudden, severe pain in the 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 someone into shock, a life-threatening condition in which the organs of the body do not get enough blood flow.
Cerebral aneurysm

If a cerebral aneurysm presses on nerves in the brain, it can cause symptoms such as:

  • 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

Symptoms of peripheral aneurysm may include:

  • A pulsating lump that can be felt in the 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 the limbs

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

Blood clots can form in peripheral aneurysms. If a clot breaks loose and travels through the bloodstream, it can lodge in an arm, leg, or brain and block the artery. An aneurysm in the neck can block the artery to the brain and cause a stroke.
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, which weakens the body's connective tissues, also can cause aneurysms. Cerebral aneurysms may occur in conjunction with polycystic kidney disease.[1]

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.
Diagnosis

An aneurysm may be diagnosed by chance during a routine physical exam. If there is an abdominal aortic aneurysm (AAA), the doctor may feel a pulsating mass in the abdomen. A rapidly growing aneurysm about to rupture can be tender and very painful when pressed. In an overweight or obese person, it may be difficult to feel an abdominal aneurysm, even if it is large.

When a stethoscope is placed over the abdomen, the normal sound of blood flowing may be replaced by a whooshing sound, which is called a bruit.

But not all aneurysms are detectable with a simple 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. Certain signs that are suspicious for aneurysm can lead the clinician to order these tests specifically to look for one.
Exams and tests

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. An ultrasound 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.
    * Computed tomography (CT). 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.
    * Magnetic resonance imaging (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 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 shows the location and size of an aortic aneurysm, and the arteries of the aorta that are involved.

Specialists

A person with an aneurysm may be referred to a cardiothoracic surgeon, vascular surgeon, or neurosurgeon. A cardiothoracic surgeon performs surgery on the heart, lungs, and other organs and structures in the chest, including the aorta. A vascular surgeon performs surgery on the abdominal aorta and on the peripheral arteries. A neurosurgeon performs surgery on the brain, including the arteries in the head, and on the spine and nerves.
Treatment

Some aneurysms, mainly small ones that are not causing pain, can be treated with watchful waiting. Others need to be treated to prevent growth and complications. The goals of treatment are to prevent the aneurysm from growing, prevent or reverse damage to other body structures, prevent or treat a rupture, and to allow the patient to continue to participate in normal daily activities.

Medicine and surgery are the two types of treatment for an aneurysm. Medicines may be prescribed before surgery or instead of surgery. They are used to reduce pressure, relax blood vessels, and reduce the risk of rupture. Beta blockers and calcium channel blockers are the medicines most commonly used.

Surgery may be recommended if an aneurysm is large and likely to rupture.
Aortic aneurysm

Some experts recommend that men who have ever smoked (at least 100 cigarettes in their lifetime) and are between the ages of 65 and 75 should have an ultrasound screening to check for abdominal aortic aneurysms.

Treatment recommendations for aortic aneurysms are based on the size of the aneurysm.

  • If the diameter of the aorta is small (less than 3 centimeters) and there are no symptoms, watchful waiting and a follow-up screening in 5 to 10 years may be all that is needed, as determined by the doctor.
    * If the aorta is between 3 and 4 centimeters (cm) in diameter, the patient is usually asked to return to the doctor every year for an ultrasound to see if the aneurysm has grown.
    * If the aorta is between 4 and 4.5 cm, testing should be repeated every 6 months.
    * If the aorta is larger than 5 cm (2 inches around, or about the size of a lemon) or growing more than 1 cm per year, surgery should be considered as soon as possible.

Two main types of surgery to repair aortic aneurysms are open abdominal or open chest repair and endovascular repair.
Open repair

The traditional and most common type of surgery for aortic aneurysms is open abdominal or open chest repair. It involves a major incision (cut) in the abdomen or chest. General anesthesia is needed with this procedure.

The aneurysm is removed and the section of aorta is replaced with an artificial graft made of material such as Dacron or Teflon. The surgery takes three to six hours, and the patient remains in the hospital for five to eight days. It often takes a month to recover from open abdominal or open chest surgery and return to full activity. Open abdominal and chest surgeries have been performed for 50 years. More than 90% of patients make a full recovery.
Endovascular repair
The illustration shows the placement of an endovascular stent graft in an aortic aneurysm. In figure A, a catheter is inserted into an artery in the groin (upper thigh). It is then threaded up to the abdominal aorta, and the stent-graft is released from the catheter. In figure B, the stent-graft allows blood to flow through the aneurysm. Source: NHLBI

In endovascular repair, the aneurysm is not removed, but a graft is inserted into the aorta to strengthen it. This type of surgery is performed through catheters (tubes) inserted into the arteries; it does not require surgically opening the chest or abdomen.

To perform endovascular repair, the doctor first inserts a catheter into an artery in the groin (upper thigh) and threads it up to the area of the aneurysm. Then, watching on live x-ray, the surgeon threads the graft (also called a stent graft) into the aorta to the aneurysm. The graft is then expanded inside the aorta and fastened in place to form a stable channel for blood flow. The graft reinforces the weakened section of the aorta to prevent the aneurysm from rupturing.

Compared to open repair, endovascular repair surgery reduces recovery time to a few days and greatly reduces time in the hospital. The procedure has been used since 1999. Not all aortic aneurysms can be repaired with this procedure, though, because the exact location or size of the aneurysm may prevent the stent graft from being safely or reliably positioned inside the aneurysm.
Cerebral aneurysm

Treatment for cerebral (brain) aneurysms depends on the size and location of the aneurysm, whether it is infected, and whether it has ruptured. A small cerebral aneurysm that hasn't burst may not need treatment. A large cerebral aneurysm may press against brain tissue, causing a severe headache or impaired vision, and is likely to burst. If the aneurysm ruptures, there will be bleeding into the brain, which will cause a stroke. If a cerebral aneurysm becomes infected, it requires immediate treatment. Treatment of many cerebral aneurysms, especially large or growing ones, involves surgery.
Peripheral aneurysm

Most peripheral aneurysms have no symptoms, especially if they are small. They seldom rupture.

Treatment of peripheral aneurysms depends on the presence of symptoms, the location of the aneurysm, and whether the blood flow through the artery is blocked. Blood clots can form in a peripheral aneurysm, break loose, and block the artery.

Aneurysms in the back of the knee that are larger than 1 inch in diameter, as well as aneurysms in the thigh, usually require surgery. An aneurysm in the thigh also is usually repaired with surgery.
Prevention

Aneurysms are best preventing by avoiding the risk factors that increase the changes of developing one. Patients should:

  • Quit smoking.
    * Eat a low-fat, low-cholesterol diet to reduce the build-up of plaque in the arteries. Plaque is a fatty buildup that narrows the arteries.
    * Control high blood pressure.
    * Control high cholesterol.
    * Get regular physical activity.

Chances of Developing an Aneurysm
Risk factors

Men are five to 10 times more likely than women to have an abdominal aortic aneurysm (AAA), the most common type.

The risk of AAA increases with age, and it is more likely to occur in people between the ages of 60 to 80. A peripheral aneurysm also is more likely to affect people ages 60 to 80. Cerebral aneurysms, though rare, are more likely to occur in people ages 35 to 60.

Factors that increase the risk for aneurysm include:

  • Atherosclerosis, a buildup of fatty deposits in the arteries
    * Smoking. Smokers are eight times more likely to develop an aneurysm than non-smokers
    * Overweight or obesity
    * Family history of aortic aneurysm, heart disease, or other diseases of the arteries
    * Certain diseases that can weaken the wall of the aorta, such as:
    o Marfan syndrome, an inherited disease in which tissues don't develop normally
    o Untreated syphilis (a very rare cause today)
    o Tuberculosis (also a very rare cause today)
    * Trauma such as a blow to the chest in a car accident
    * Severe and persistent high blood pressure between the ages of 35 and 60; this increases the risk for a cerebral aneurysm
    * Stimulant drugs like cocaine

Clinical Trials

For a list of government-sponsored clinical trials, visit aneurysm trials.
References

1. ↑ Chapman AB, Rubinstein D, Hughes R et al. Intracranial aneurysms in autosomal dominant polycystic kidney disease. N Engl J Med. 1992 Sep 24;327(13):916-20. Abstract

External Links

Vascular Disease Foundation: Abdominal Aortic Aneurysm: What Is It?

Society for Vascular Surgery:

  • Aortic Aneurysms
    * Peripheral Aneurysms

Society of Thoracic Surgeons: Aortic Aneurysm

National Institute of Neurological Disorders and Stroke: Cerebral Aneurysm Fact Sheet

Brain Aneurysm Foundation: Brain Aneurysm Basics

Wikisurgery Surgical Scripts: Operative Script of Abdominal Aortic Aneurysm Graft

Source: Article used in its entirety from Medpedia.com: http://wiki.medpedia.com/Aneurysm

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