Brain Aneurysms
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 Aneurysm Fusiform Aneurysm Raptured Aneurysm
Saccular (sac) shaped) aneurysms: They are the most common type of aneurysm and occur 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. Another important reason for the formation of aneurysms is the loss of elasticity of the vessel wall as a result of the deterioration of the vascular structure in older ages.
Fusiform (spindle-shaped) aneurysms: This aneurysm is seen as a spindle-shaped expansion that includes 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 coagulation and detachable debris that may cause blockage (embolism) in normal brain vessels, causing symptoms similar to stroke and ruptured aneurysm.
Mycotic (inflammation)-like symptoms. 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 weakening the wall and causing aneurysm formation. The risk of rupture increases. Often to subacute bacteria! It is a complication of endocarditis (known as 'heart rheumatism' in our society).
Traumatic (accidental) aneurysms: This is a type of aneurysm that develops after an accident in the brain blood vessels. The damaged vascular wall in the trauma area weakens and may subsequently rupture.
Prevalence and Frequency in the Society
The frequency of brain hemorrhage due to brain 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 is increasing 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
7) Some infections
Symptoms/Warning Signs
Some warning signs may be seen in patients with aneurysm rupture/bleeding:
· Persistent headache in any area
· Nausea and vomiting
· Stiffness in the neck (the person cannot bend his head easily)
· Blurred or double vision
· Sensitivity to light (photophobia)
· Sensation defects
K Most people with an unruptured aneurysm may have no symptoms. Some or all of the following symptoms may be seen in a small group of patients:
· Paralysis of the optic nerves (such as drooping eyelid, inability to move the eye easily)
· One-sided dilated pupil
· Double vision , pain behind or above the eye
· Persistent headache in one area
· Progressive weakness and numbness
Risks and Complications
When aneurysms rupture, they often Bleeding (SAH) develops between the thin membrane of the brain. 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 prevention of rebleeding. The probability of bleeding again after a bleed 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 can cause damage by causing pressure on the surrounding brain tissue without bleeding. In addition, clots may develop in large aneurysms and pieces that break off may cause many strokes.
Blood leaking around the brain may cause narrowing (vasospasm) in the vessels. This may cause a decrease in blood flow to the brain tissue and therefore a stroke. Vasospasm usually occurs 5 days before bleeding. -Develops after 8 days. It is very difficult to treat and may endanger the patient's life. Blood leaking from a ruptured aneurysm may 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 may also cause brain 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 and slow down blood flow to the brain.
Diagnostic Methods
According to the medical regulations in force in our country, patients with brain aneurysms can only be hospitalized under the supervision of brain and neurosurgeons. The diagnosis of a patient with ruptured brain aneurysm can be accurately determined by examination, but additional tests are needed to confirm the diagnosis. In this regard, the disease history should be explained well to the physician (all relevant illnesses in the past should be reported). Since there is a possibility of additional aneurysms in such a patient, it is vital to use correct diagnostic tests. The physician needs the correct information for the correct test to reach the diagnosis.
Brain Angiography: This test is the most valid method for detecting aneurysms. To perform the test, it is necessary to know the patient's blood table; This test cannot be performed in patients with a tendency to bleeding. Angiography is generally performed by the radiology department, but with the new regulation, neurology and neurosurgery departments have also started to perform this practice. Although mild sedation with medication may sometimes be needed during the procedure, it can generally be done while the patient is awake.
While the patient lies on the examination table, the person who will perform the angiography enters the artery from the groin with a thin needle. A small plastic tube (catheter) is then placed into the vein. The passage of the catheter is visualized under x-rays and proceeds to the head and neck region, where the four main brain vessels are located. There is no pain during this procedure. Each brain horse Visible intravenous dye is administered separately to the artery, and x-ray images are taken at this time. This application allows the vessels to be seen clearly.
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After the angiography images are taken, the catheter is removed and a pressure dressing is applied to the removed area to prevent blood leakage. After a period of observation, the patient is sent to his bed. The patient does not feel the passage of the catheter during the procedure, but during the administration of the dye used, a vague feeling may occur on one side of the head or may cause temporary stargazing or neck cramps. Although angiography is sensitive and specific in detecting brain aneurysms that can put a person's life at risk, it is ultimately an invasive procedure for the patient and carries a low risk of damage to the vessel wall, stroke, and allergic reaction to the dye used.
Computed Tomography-Angiography (CTA): It is a newer technology and images similar to conventional angiography are taken by administering dye material through a vein in the patient's arm. The risk of the procedure is the allergy caused by the dye, which is also described in conventional angiography, and the potential damage it may cause to the kidneys. An important advantage of this method is that there is no need to transfer the patient to the angiography unit and there is no need for additional personnel. The imaging process is completed in less than a minute and does not pose a risk of stroke.
Magnetic Resonance Imaging (MRI): It is a diagnostic test that provides three-dimensional images of the body's organs using magnetic field and computer technology. Provides clear images of brain anatomy. Brain MRI may also show signs of pre-existing minor strokes. It is a test that does not harm the patient, but since the inside of the device is narrow, some people may experience claustrophobia. In addition, problems may be encountered in people who are not allowed to enter the magnetic field (such as those who have a coronary stent or magnetic prosthesis in their body).
Angiography (MRA): It is a test that can be performed with an MR imaging device and does not harm the patient. Magnetic images are analyzed by a computer and the veins of the head and neck area are displayed. MRA shows actual blood vessels and shows blocked, narrow ones.
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