Cerebral Aneurysm

The word aneurysm comes from the latin word aneurysma, which means dilation. An aneurysm is an abnormal local dilation in the wall of a blood vessel, usually an artery. It can be caused by a defect, a disease, or an injury. A cerebral aneurysm is an abnormal focal dilation of an artery located in the brain that results from a weakening of the inner muscular layer called the intima of a blood vessel wall (Brisman, 2014). The vessel develops a blister-like dilation that becomes thin and may rupture without warning. The rupture causes bleeding into the space around the brain which produces a subarachnoid hemorrhage (SAH). This kind of hemorrhage can lead to a stroke, coma , and/or death (Singla & Hoh, 2015). The most common place for a cerebral

aneurysm to form is within the circle of willis. The circle of willis is composed of multiple paths through which nutrients such as oxygenated blood and glucose are supplied to the brain.

It is the junction of two carotid arteries and two vertebral arteries. This junction, where the arteries all come together, has a high possibility of forming weak spots that become more prone to fill up with blood and balloon out forming a sac-shaped aneurysm (Wedro, 2016). Smaller arteries branch out from this center and supply oxygenated blood to 80% of the cerebrum (Kantor, 2015).

Cerebral aneurysms are all different. They vary in shape, size, and location. Cerebral aneurysms are classified into three basic types based on their shape. These types are saccular, lateral, and fusiform (Zuccarello, 2016). Saccular aneurysms account for 90% of all aneurysm shape types (Buckley, 2016). This type forms a sac outside the artery that looks like a berry, therefore commonly referred to as a “berry aneurysm” (Brisman, 2014). It is attached by a neck of stem to an artery or a branch of a blood vessel. It is usually located on arteries at the base of the brain. A lateral 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 (Koroshetz, 2015). Another type of cerebral aneurysm is a traumatic aneurysm. This type is named using the method by which it began to develop. A traumatic aneurysm is caused by a closed head injury or penetrating trauma to the brain (Zuccarello, 2016). A fusiform aneurysm is an uncommon type that causes the artery to bulge all the way around. There is also a dissecting aneurysm which is a tear in one of the several linings of an artery. It can leak blood into the other layers and balloon out or block the artery (Buckley, 2016). Cerebral aneurysms also range in sizes from small to giant. Small aneurysms measure less than ¼ of an inch, medium aneurysms are ¼ to ¾ of an inch, large aneurysms are ¾ to 1 ¼ of an inch, and the most dangerous are giant aneurysms which are larger than 1 ¼ of an inch. Giant aneurysms pose a higher risk due to their size and difficulty to be treated. A cerebral aneurysm is usually located along the major arteries deep within the brain structures just inside the skull in an area called the subarachnoid space (Singla & Hoh, 2015). They can however develop in the front part of the brain (anterior circulation) of in the back part of the brain (posterior circulation) (Wedro, 2015).
The true cause of cerebral aneurysms are unknown; however, the following factors are believed to contribute to their formation. Such factors include hypertension also known as high blood pressure, cigarette smoking, congenital (genetic) predisposition, injury or trauma to blood vessels, or complications from some types of blood infections (Singla & Hoh, 2015). A common genetic factor is atherosclerosis which is hardening of the arteries. This along with aging gives a person the tendency to form aneurysms (Thompson, 2016).
Most unruptured cerebral aneurysms are asymptomatic meaning that they do not express any symptoms. These aneurysms are usually only discovered incidentally during tests for another usually unrelated condition. Due to this, many people carry on with their lives performing their daily routines unaware that a brain aneurysm is present. This is the case for small aneurysms; however, large unruptured aneurysms can occasionally press on the brain or on the nerves stemming out of the brain and may result in various neurological symptoms. Symptoms include a localized headache, dilated pupils, blurred or double vision, pain above and behind the eye, weakness and numbness, and difficulty speaking. More severe symptoms occur when the aneurysm is ruptured resulting in a subarachnoid hemorrhage. When blood begins to fill the subarachnoid space, it causes the following symptoms: sudden severe headache (“ the worst headache of your life”), loss of consciousness, nausea/vomiting, stiff neck, sudden trouble walking or dizziness, or seizures. Individuals experiencing any of these symptoms are advised to seek medical attention immediately (Buckley, 2016). Those individuals more prone to develop cerebral aneurysms can get tests by computerized tomography (CT) or magnetic resonance imaging (MRI) scans that take pictures of the brain tissues and arteries. CT scans are usually better at revealing any cranial bleeding that may already be present (Macon & Solan, 2015). Another test is a spinal tap. During this procedure a doctor draws fluid from the spine to check for signs of bleeding in the brain. Cerebral angiograms are also used to check for bleeding and any abnormalities in the brain arteries (Macon & Solan, 2015).
Cerebral aneurysms can either be true or false. A false aneurysm is a cavity lined by a blood clot and is not as dangerous as a true aneurysm (Brisman, 2014). For a ruptured aneurysm, there is no doubt of how to proceed with treatment. Ruptured aneurysms undergo surgery when they are secured with clips or coils to prevent re-rupture (Singla & Hoh, 2015). If the aneurysm is true and unruptured, there are more treatment options. If an individual has an unruptured aneurysm they can choose between treatment procedures or observation (Brisman, 2014). In a light approach, doctors can prescribe pain medication to soothe headache and eye pain caused by the aneurysm. They can also prescribe medication aimed at preventing blockage of the blood vessels to relieve cranial pressure (Macon & Solan, 2015).The other three common treatment options are medical therapy which is non-surgical, surgical therapy or clipping, or endovascular therapy or coiling with or without adjunctive devices (Singla & Hoh, 2015). The exact method of treatment will be determined by your physician. Factors size, location, severity of symptoms, patient’s age and medical condition are all taken into account (Solomon, 2016).
Medical therapy is only an option for unruptured intracranial aneurysms. It takes an approach on the lifestyle of the patient in an attempt to reduce the level of risk for rupture. Strategies include smoking cessation and blood pressure control. These two are the main focus for health providers as research has shown that they have a greater significant effect on aneurysm formation, growth, and/or rupture (Singla & Hoh, 2015). The other two primary treatment options are both surgical procedures. If the aneurysm is accessible, surgery can repair or cut off blood flow to the aneurysm. This can help prevent further growth or a rupture (Macon & Solan, 2015). The first option is open craniotomy referred to as surgical clipping. This procedure was first introduced in 1937 by Walter Dandy (Singla & Hoh, 2015). The procedure involves the surgical removal of part of the skull. After exposing the aneurysm, the physician places a metal clip across the neck of the aneurysm to prevent the continual blood flow into the aneurysm sac. Once the clipping is complete, the skull is sutured back together (Solomon, 2016). Since the first use of clipping, improvements have been made to vary the size and shape of the clips used. Both improvements in technology and the variety of clips have coined this procedure the gold standard (Singla & Hoh, 2015). The other surgical approach is endovascular coiling or coil embolization. This is considered a minimally invasive technique meaning an incision in the skull is not required to treat the cerebral aneurysm. In this approach, a catheter is advanced from a blood vessel in the groin up into the blood vessels in the brain with the use of a fluoroscopy, a special type of x-ray. Once the catheter is set in place, very tiny platinum coils are advanced through the catheter into the aneurysm. When inside the aneurysm, these soft coils conform to the shape of the aneurysm. The coiled aneurysm then becomes clotted off, preventing rupture (Solomon, 2016). Regardless of the approach to treat the aneurysm, the main concern is to decrease the risk of a subarachnoid hemorrhage initially or from rerupture (Macon & Solan, 2015).
About three to five million people in the United States have cerebral aneurysms.

Aneurysms can be present in anybody at any age (Koroshetz, 2015). They usually do not exhibit any symptoms or dangers if unruptured. The following risk factors however may increase your risk for a ruptured cerebral aneurysm. They are age, family history, previous aneurysm, gender, race, high blood pressure, smoking, and drug and alcohol abuse (Koroshetz, 2015). Cerebral aneurysms are rarely developed in infants and children. Manifestation increases directly with age eventually reaching its peak among those between the ages of 55-60 (Liebeskind, 2015). Women are more likely to develop a brain aneurysms or to suffer a subarachnoid hemorrhage than men. African Americans are more prone than whites to suffer from subarachnoid hemorrhage. Those with high blood pressure or habits of smoking also increase their chances of a brain aneurysm rupturing. That being stated, not all aneurysms will rupture. An estimated 50 to 80 percent of all aneurysms never rupture in a person’s lifetime (Liebeskind, 2015). The true danger with a cerebral aneurysm is the possibility of it rupturing and bleeding into the brain. This bleeding can lead to a hemorrhagic stroke, permanent nerve damage, or death. Once an aneurysm bursts it can rerupture and continue bleeding into the brain while forming additional aneurysms. Bleeding into the brain lasts only a few seconds, but if can cause very severe complications. Commonly the

rupture leads to a subarachnoid hemorrhage that causes hydrocephalus or vasospasm. Hydrocephalus is a delayed but serious complication in which the excessive buildup of cerebrospinal fluid in the skull dilated fluid pathways called ventricles that can swell and press on the brain tissue. Vasospasm is another delayed post rupture complication in which other blood vessels in the brian contract and limit blood flow to vital areas of the brain. This reduced blood flow can then cause stroke or tissue damage (Koroshetz, 2015). The most severe result is the increased pressure that the blood puts on the skull. If the pressure becomes too elevated, the blood and oxygen level may be disrupted to the point that loss of consciousness or death can occur (Wedro, 2015).
In conclusion, cerebral aneurysms may arise due to hereditary factors making it unpreventable in some cases. However, by taking certain steps to maintain a healthy circulatory system by not smoking, working out, and eating right an individual can easily decrease the risks associated with developing cerebral aneurysms. Many individuals continue to live a healthy symptom free lifestyle unaware of the presence of a brain aneurysm. Most cases of small aneurysms cause no harm. The true problem arises with an aneurysms potential to rupture, even if more than half of them never do. Unless the aneurysm ruptures, there is no need to proceed with treatment. Treatment procedures include surgical and nonsurgical options.