What is a Brain Aneurysm?
Aneurysm is a ballooning that occurs as a result of the weakening of the artery wall in the brain and is often seen in the bifurcation areas of the vessels. This ballooned structure is more flimsy than a normal vein, and under some conditions it may rupture and cause bleeding into the brain, endangering life. Aneurysms may be due to congenital vascular maldevelopment, or may develop after high blood pressure, arteriosclerosis (atherosclerosis), infections (inflammation of the vessel) or head trauma. Aneurysms are usually located at the base of the brain and cause bleeding in the cerebrospinal fluid there. The annual bleeding risk of aneurysms is approximately 1%.
Aneurysm Types Saccular
(sac-shaped) aneurysms: It is the most common type of aneurysm and occurs in the bifurcation areas of large vessels at the base of the brain. At these bifurcation points, the vessel wall is exposed to more pressure. This constant pressure may cause ballooning over time as a result of damage to the vessel wall. Saccular aneurysms develop over years, and therefore the risk of aneurysm rupture increases with age. We can compare this development of an aneurysm to the ballooning seen in the inner tubes used in vehicles in the past. Loss of elasticity of the vessel wall as a result of deterioration of the vascular structure in older ages is another important reason for the formation of aneurysms.
Fusiform (spindle-shaped) aneurysms: This aneurysm is seen as a spindle-shaped expansion containing a long section of the vessel. These types of aneurysms may rupture and bleed, expand to a great extent and cause pressure on the surrounding brain tissue, or cause clotting and detachable residues that cause blockage (embolism) in normal brain vessels, causing stroke-like complaints
Mycotic (developing as a result of inflammation) Aneurysms: They are rare and develop as a result of microbial disease of the vessel. They are generally sac-shaped. Inflammation causes damage to the vessel wall, thus increasing the risk of aneurysm formation and rupture as a result of wall weakening. It is often a complication of subacute bacterial endocarditis (known as 'heart rheumatism' in our society).
Prevalence and Frequency in the Society
B The frequency of cerebral hemorrhage due to cerebral aneurysm is around 10-15 per 100,000 people per year. It can be assumed that an average of 10,000 people every year in our country are at risk of brain hemorrhage due to aneurysm. Approximately 1/3 of these patients die before they can contact any health institution. The mortality rate in bleeding patients who can apply to a healthcare facility is between 25-40%. Therefore, nearly half of the patients whose aneurysm ruptures die. An important point here is the early diagnosis and treatment of brain aneurysms that have not yet bleed but still put the patient at risk. Aneurysms can be seen in all age groups, but the frequency gradually increases in those aged 25 and above. Its prevalence is most common between the ages of 50-60 and it is 3 times more common in women than in men. Having a family history of aneurysms increases the risk of having aneurysms in other family members. Having more than one aneurysm at the same time in a person increases this risk even more. Although the exact cause of aneurysm formation is not known, it is known that many factors play a role in its development: 1) Hypertension (high blood pressure); 2) Smoking/nicotine use; 3) Diabetes; 4) Excessive alcohol consumption; 5) Congenital (genetic) predisposition; 6) Damage to blood vessels (especially atherosclerosis) or trauma and 7) Some infections
Complications
When aneurysms rupture, subarachnoid (between the brain and the thin membrane of the brain) bleeding (SAH) often develops. Blood passing from the vein to the subarachnoid space at high pressure may accumulate there and cause pressure on the brain. Bleeding may also occur inside the brain; Blood elements can also reach the spinal cord environment, which has lower pressure. Bleeding from the aneurysm can sometimes occur in the form of leakage; In this case, a small clot may form at the leak point and stop the bleeding, and the patient may survive. However, this process caused by the clot does not prevent the risk of rebleeding; With each additional bleeding, life becomes more endangered and the likelihood of survival decreases. The cause of most spontaneous SAHs is aneurysms. Exactly determining the location, size and configuration of the aneurysm is a critical point in its treatment and therefore in preventing rebleeding. Bleeding again after a bleed The probability of a is around 20% for the first 14 days. As mentioned above, aneurysm bleeding is fatal at rates of up to 50%. It also causes permanent neurological disorders in 25% of living patients. In addition to mental functions, impairment of all body functions (for example, partial paralysis) may occur. In more serious cases, bleeding can cause severe damage to brain cells and put the patient into a coma. If the aneurysm is large, it may damage the surrounding brain tissue by causing pressure without bleeding. In addition, clots may develop in large aneurysms and pieces that break off may cause many strokes. Blood leaking around the brain can cause narrowing of the vessels (vasospasm). This may cause a decrease in blood flow to the brain tissue and therefore a stroke. Vasospasm usually develops 5-8 days after bleeding. It is very difficult to treat and may endanger the patient's life. Blood leaking from a ruptured aneurysm can block the cerebrospinal fluid (CSF) circulation, causing the condition we call hydrocephalus (excessive fluid accumulation in the brain). In this case, excessive fluid may accumulate in the spaces in the brain called ventricles, causing intracranial pressure to increase. In order to prevent this fluid increase, a drain should be placed in these cavities and the accumulated fluid and leaked blood should be removed. Aneurysm bleeding can also cause cerebral edema or swelling. This situation affects brain functions and causes very serious problems. Swelling and increased pressure of the brain tissue damages the brain tissue. Cerebral edema can cause pressure on blood vessels, slowing down blood flow to the brain
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