An aneurysm is a swelling in part of an artery caused by damage to, or weakness of, a blood vessel wall. The pressure of blood in the artery causes it to ‘balloon’ out at the weak point. The swelling may be small, spherical and berry-size, which normally occurs near blood vessel branches, or larger and balloon-like. Large aneurysms may also extend along arteries.
Aneurysms may occur anywhere in the body, but they are most common on the largest artery in the body, the aorta, and on the small circle of arteries underneath the base of the brain called the Circle of Willis.
An aneurysm can also occur on the heart wall after a section has been weakened by local loss of blood supply from a heart attack (myocardial infarction).
Aneurysms may affect people of any age and both sexes, although they are more common in men, people with high blood pressure and those over 65. Aortic aneurysms tend to run in families. Aneurysms are fatal if they burst.
The cause of most aneurysms is unknown although aneurysms of larger arteries, such as the aorta, are thought to be largely due to build-up of fat in artery walls (atherosclerosis). Anyone can develop atherosclerosis, but it is more common with increasing age. Certain 'risk factors' also increase the chance of atherosclerosis developing; these include smoking, high blood pressure, diabetes, raised cholesterol level, taking little exercise, and obesity.
Brain aneurysms are due in most cases to a weakness in the artery wall that has been present from birth. They may also be linked to high blood pressure and arteriosclerosis.
An aneurysm can be caused by an injury to an artery that does not rupture the wall but weakens it, so that blood pressure gradually causes the blood vessel to balloon out. An example of this would be a crush injury to the chest such as may be sustained in a car crash. Another much less common cause of aortic aneurysm is the genetic disease, Marfan syndrome.
The symptoms of an aneurysm depend on its size and rate of growth. A small, unchanging aneurysm will generally produce no symptoms, and you may not be aware of it. Larger aneurysms of the brain (cerebral aneurysm) may press on nerve tissue causing a loss of feeling in the face or problems with the eyes. Immediately before an aneurysm ruptures, you may experience the following symptoms:
a sudden and usually severe headache,
nausea,
vision impairment,
vomiting, and
loss of consciousness.
Rupture of a cerebral aneurysm usually results in bleeding in the brain, causing a haemorrhagic stroke. Blood can also leak into the area surrounding the brain, causing a blood clot within the skull (intracranial haematoma).
Most aortic aneurysms occur in the abdominal aorta. Many people have this type of aneurysm for years before they notice any symptoms. Symptoms vary depending on the type and location of the aneurysm, but can include:
a pulsating feeling in the abdomen,
back pain, and
abdominal pain (that may go towards the back).
Many aortic aneurysms are discovered while your GP is looking for something else. The main sign of an aortic aneurysm is a lump in the abdomen, high up and a little to the right, that pulses obviously with the heartbeat. This is usually discovered during a routine examination of the abdomen.
The increasing swelling of an aneurysm of the aorta may press on the spine and chest organs. This can cause pain, coughing, loss of voice, and difficulty in swallowing and sometimes breathing.
Sometimes a doctor feels the bulge of an aortic aneurysm during a routine examination of the abdomen.
An ultrasound scan is the usual procedure for diagnosing an aneurysm of the aorta. This is a painless test that is also able to measure the size of the aneurysm. This can be an important factor when deciding on treatment.
An aneurysm of the brain can be detected by a special kind of X-ray called an angiogram or arteriogram. To show up the aneurysm, a dye that is opaque to X-rays is injected into the bloodstream. The blood in the vessels shows up on the film as white columns. If there is a swelling on an artery, the dye in the blood will pass into it and the X-ray will show a swelling.
More detailed scans, such as a CT scan, may be used to find out if the aneurysm is affecting any of the arteries that come off the aorta. For instance, if the aneurysm involves the arteries to the kidneys then surgeons need this information if they plan to operate.
Treatment of aneurysms depends on how big they are. Surgery to repair an aortic aneurysm is a major operation, and it is not usually recommended unless the aneurysm is large (bigger than 55mm wide). The surgical procedure involves replacing the part of the aorta affected by the aneurysm with a synthetic graft. This a tube made out of an elastic material that is very similar to a normal healthy aorta.
For small aortic aneurysms, (less than 55mm wide), the risk of death caused by surgery is generally more than the risk of the aneurysm rupturing. However, you must continue to have regular medical check ups to make sure the aneurysm is not growing.
For brain aneurysms, a specialised surgical procedure called a craniotomy is carried out to open the head. The aneurysm is found using a microscope, and a metal clip is used to clip the neck of the aneurysm. This seals it off without damaging the main artery. Sometimes the aneurysm is packed with a special type of glue to encourage the blood to clot and strong tissue to form. Sometimes the aneurysm may be managed with radiotherapy.
Aneurysm surgery is a major operation, and you will usually be kept in intensive care for one to two weeks afterwards to monitor your progress. It is very important to avoid any strain or exertion, and drugs are given to keep the blood pressure reasonably low. A drip will be used to make sure you get all the fluids you need.
Sometimes, the blood vessels can go into spasms following this type of operation. Drugs are given to control this and reduce the chance of brain damage. It is also important to prevent the clot that is forming in the aneurysm from dissolving. Antifibrinolytic drugs to prevent clots dissolving will often prevent re-bleeding from a dissolving clot.
Sometimes a doctor feels the bulge of an aortic aneurysm during a routine examination of the abdomen.
An ultrasound scan is the usual procedure for diagnosing an aneurysm of the aorta. This is a painless test that is also able to measure the size of the aneurysm. This can be an important factor when deciding on treatment.
An aneurysm of the brain can be detected by a special kind of X-ray called an angiogram or arteriogram. To show up the aneurysm, a dye that is opaque to X-rays is injected into the bloodstream. The blood in the vessels shows up on the film as white columns. If there is a swelling on an artery, the dye in the blood will pass into it and the X-ray will show a swelling.
More detailed scans, such as a CT scan, may be used to find out if the aneurysm is affecting any of the arteries that come off the aorta. For instance, if the aneurysm involves the arteries to the kidneys then surgeons need this information if they plan to operate.
An aneurysm under the brain may burst, causing serious bleeding into the fluid surrounding the brain. This is called a subarachnoid haemorrhage and causes very severe headache, usually followed rapidly by loss of consciousness or other signs of damage to the brain. There may be neck stiffness, vomiting, weakness or paralysis of various parts of the body, and even death.
An aneurysm of the aorta may also leak. This, too, is an emergency situation. Rupture of an aortic aneurysm, particularly a large one, often causes death.
source NHSDirect 151204
Product code:sym-aneurysm |
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