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May 14, 2006
Cerebrovascular disorders: Cerebral Brain Aneurysm
by SirGan|
Cerebral or brain aneurysm is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. In most cases, an aneurysm can go undetected and produce no signs or symptoms. So, it can be really a little risk to a person’s health! Problem is that some brain aneurysms are large enough to put pressure on surrounding brain tissue or even they can rupture at a weak spot in the artery wall, causing massive bleeding in that specific area of brain. People of all ages can have a brain aneurysm, but most develop as a result of aging. Most are discovered in people ages 35 to 60. Women are slightly more likely to develop an aneurysm than men are.
Types of aneurysmsThere are three types of cerebral aneurysm.
A saccular aneurysm is a rounded or pouch-like sac of blood that is attached by a neck or stem to an artery or a branch of a blood vessel. It is also known as a berry aneurysm- because it resembles a berry. This most common form of cerebral aneurysm is typically found on arteries at the base of the brain. Saccular aneurysms occur most often in adults. A lateral, or dissecting aneurysm appears as a bulge on one wall of the blood vessel, while a fusiform aneurysm is formed by the widening along all walls of the vessel.
Incidence and risk factorsAll cerebral aneurysms have the potential to rupture and cause bleeding within the brain.
There are a few factors which are clearly associated with an increased risk of rupture:
Symptoms of brain aneurysmMost cerebral aneurysms do not show symptoms until they either become very large or burst to surrounding tissue. So, there small aneurysms generally will not produce symptoms. If the aneurysm is bigger, then- it may press on tissues and nerves.
Symptoms may include:
When an aneurysm hemorrhages, an individual may experience:
Possible causesMost brain aneurysms develop as a result of the wear and tear on arteries that comes with aging. Several researches proved that brain aneurysms aren't present at birth (congenital), as once was commonly believed. However, some people may have a predisposition to developing an aneurysm. Cerebral aneurysms are also more common in people with certain genetic diseases, such as connective tissue disorders and polycystic kidney disease, and certain circulatory disorders, such as arteriovenous malformations
Rarely, a blow to your head or an infection in an artery can weaken an artery wall and result in an aneurysm. Other causes include:
Some experts believe that the oral contraceptives may also increase the risk of developing aneurysms.
Associated conditionsConditions that have been associated with increased incidence of cerebral aneurysms are:
Localization of aneurysmsIt is proven that aneurysms commonly arise at the bifurcations of major arteries. Most of the aneurysms arise on the circle of Willis, located on the brain base!
Approximately 85% of all intracranial aneurysms arise on the anterior or carotid circulation. Common locations are:
About 15% of all intracranial aneurysms arise on the posterior or vertebrobasilar circulation.
Saccular aneurysms are uncommon in locations other than the circle of Willis, the MCA bifurcation, or the pericallosal artery origin.
Subarachnoid hemorrhageThe Subarachnoid hemorrhage or bleeding is the most common clinical manifestation of brain aneurysm. The most widely used clinical method for grading the clinical severity of SAH is the Hunt and Hess scale. Grades are:
Screening and diagnosisThere is a great chance that the aneurysm will go undetected, especially, if it didn’t ruptured! However, after an aneurysm has ruptured, there are a number of ways to confirm diagnosis. Besides physical exam and a neurological exam, neurological exam includes checking memory and concentration, vision, hearing, balance, coordination and reflexes. Other tests include:
A head CT scan can reveal the presence of a suspected aneurysm and show whether blood has leaked from the artery into brain. Similar to an X-ray, a CT scan shows a more detailed image of your brain than a conventional X-ray can because it uses computer based reconstructions. Some scans involve use of a contrast dye injected into your vein. Known as CT angiography, this test produces an even more detailed image.
It is probably the best possible diagnostic tool for the detection of aneurysms. This type of imaging uses a magnetic field and radio waves to create detailed, cross-sectional images of brain. When this diagnostic test involves use of a contrast, it's known as magnetic resonance angiography.
During this invasive procedure, doctor inserts a thin, flexible tube called catheter into a large artery usually located groin region and guides it! The catheter pasts your heart and enters the cerebral arteries in your brain. A cerebral arteriogram provides a clear picture of the arterial blood flow in your head.
This procedure, also known as a spinal tap, involves the use of a needle to extract a small amount of the fluid that protects your brain and spinal cord called liquor. Analysis of the fluid can detect brain hemorrhage very easily because it should be red colored! In patients with suspected subarachnoid hemorrhage, this procedure is usually done in a hospital.
Possible complications of brain aneurysmsA brain aneurysm that bursts can cause
A ruptured aneurysm on the surface of the brain causes a subarachnoid hemorrhage, bleeding into the space between your brain and your skull. Other possible complications include:
Treatment of brain aneurysmsTwo surgical options are available for treating cerebral aneurysms, both of which carry some risk to the patient.
It is one of the most effective methods and it involves cutting off the flow of blood to the aneurysm. The neurosurgeon uses isolates the blood vessel that feeds the aneurysm and places a small, metal clip on the aneurysm, halting its blood supply. Clipping has been shown to be highly effective, depending on the location, shape, and size of the aneurysm. In general, it is proven that aneurysms that are completely clipped surgically do not return.
During this procedure the surgeon clamps off the entire artery that leads to the aneurysm.
This procedure is often performed when the aneurysm has damaged the artery. An occlusion is sometimes accompanied by a bypass.
Endovascular embolizationEndovascular embolization is an alternative to surgery. It is about inserting a catheter into an artery and guiding it, through the body to the site of the aneurysm. Using a guide wire, detachable coils or small latex balloons are passed through the catheter and released into the aneurysm. The coils or balloons fill the aneurysm; block it from circulation, and cause the blood to clot, which effectively destroys the aneurysm.
PreventionThere are no known ways to prevent a cerebral aneurysm from forming and that’s a fact. The fact is also that people with a diagnosed brain aneurysm should carefully control high blood pressure, stop smoking, and avoid cocaine use or other stimulant drugs. Women should check with their doctors about the use of oral contraceptives.
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