Brain aneurysm

Cerebral aneurysm . It is a fatal disease, but with the latest advances in technology and new pharmacological findings, its mortality rate has been considerably reduced. However, the cerebral aneurysm remains an unknown evil.


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  • 1 Origin
  • 2 How it occurs
  • 3 Why does a brain aneurysm form?
  • 4 Risk factors
  • 5 Other factors
  • 6 Causes
  • 7 Symptoms
  • 8 Signs and tests
  • 9 Diagnosis
  • 10 Treatment
  • 11 Expectations
  • 12 Complications
    • 1 Situations requiring medical assistance
  • 13 Prevention
  • 14 Sources


Aneurysms (word that in its Greek origins means to widen) are the dilations that occur in arterial walls, due to congenital or acquired defects, and that in the course of their evolution can suffer ruptures, causing bleeding. The symptoms and severity will be given by their size and location. Dr. Carlos Suárez Monteagudo, Chief Neurologist of the CIREN Clinic for Attention to Static Brain Injuries, in Havana City, reports that aneurysms generally occur at the bifurcations of the arteries, most frequently in the great cerebral vessels of the aortic artery, mainly due to be the ones that receive the highest blood pressure in the process of blood circulation. As intracranial aneurysms are among the most frequent, and precisely because my interlocutor is a specialist in Neurology, we limit today’s topic to these strokes.

How it occurs

A brain aneurysm usually occurs in an artery at the front of the brain that supplies oxygen-rich blood to brain tissue. A normal artery wall consists of three layers. The aneurysm wall is thin and weak due to the loss or abnormal absence of the muscular layer of the artery wall, leaving only two layers. The most common type of cerebral aneurysm is called a saccular or berry aneurysm , and it represents 90% of cerebral aneurysms. It looks like a “berry” with a narrow stem. More than one aneurysm may occur at a time. Two other types of brain aneurysms are fusiform aneurysms.and dissecting. A fusiform aneurysm protrudes from all sides (in the form of a circumference). It is usually associated with atherosclerosis . A dissecting aneurysm can be caused by a tear in the inner layer of the artery wall, which allows blood to enter the layers. This can stretch one side of the artery wall, or it can block or obstruct blood flow through it. Dissecting aneurysms can occur with traumatic injuries. The shape and location of the aneurysm may influence the type of treatment.

Why does a brain aneurysm form?

Currently, the exact cause of the brain aneurysm is unknown. The formation of the saccular cerebral aneurysm is mainly associated with two factors: an abnormal degenerative change (decomposition) in the artery wall, and the effects of the pressure of the pulsations of the blood pumped through the arteries in the brain. Certain locations of an aneurysm can put great pressure on the aneurysm, such as at a bifurcation (where the artery divides). The formation of a cerebral aneurysm was also linked to hereditary risk factors or later development factors (acquired risk factors).

Risk factor’s

Hereditary risk factors associated with atherosclerosis include, but are not limited to:

  • Alpha-glucosidasedeficiency: A total or partial deficiency of the lysosomal enzyme, alpha-glucosidase. This enzyme is necessary to break down glycogen and convert it to glucose.
  • Deficiency alpha-1-antitrypsin: A hereditary disease that can cause hepatitis and liver cirrhosis or emphysema .
  • Arteriovenous malformation(AVM): Abnormal communication between an artery and a vein.
  • Coarctation of the aorta: Narrowing of the aorta (the main artery that comes from the heart).

Ehlers-Danlos syndrome: connective tissue disorder (less common).

  • Family history of aneurysms.
  • To be a woman.
  • Fibromuscular dysplasia: arterial disease, of unknown cause, which mainly affects the medium and large arteries of young and middle-aged women.

Other factors

They can be congenital due to a constitutional alteration of the middle layer of the vessel wall, or secondary to an injury to its most intimate layer with fragmentation of its structures, due to an inflammatory or arteriosclerotic nature, among the most frequent. And those of genetic origin? Hereditary factors in the formation of cerebral aneurysms are alleged. Research on its family incidence supports this hypothesis, since aneurysms are found in several members of the same family. Aneurysms, with a similar location, have also been described in twins and even intracranial aneurysms associated with certain congenital alterations and malformations such as polycystic kidney . However, sporadic cases, without a family or hereditary link, are frequent.


  • Congenital weakness of the blood vessels.
  • High blood pressure.
  • Being a smoker.
  • Blockage in the arteries.


Symptoms don’t usually appear until complications occur. Bleeding is the main cause of symptoms, with bleeding being the most frequent type of bleeding. Weakness, numbness, or other loss of nerve function ( neurological deficits ) may appear due to the pressure the aneurysm exerts on the adjacent brain tissue or due to a reduction in blood flow as a result of the spasm of other blood vessels near the rupture of an aneurysm. In addition there are other more appreciable symptoms such as: sudden headache (severe or described ‘as the worst that has been suffered’), headache with nausea and vomiting, stiff neck (occasionally), muscle weakness, difficulty moving any part of the body, numbness or less sensitivity of any part of the body, eye disorders (double vision, loss of vision), drooping of the eyelids, changes in mental state, the person may be confused, lethargic, sleepy or stuporous, epileptic seizures, lethargic movements , speech disorders, irritability or lack of control. The symptoms that determine the irruption of a cerebral aneurysm are extreme, since it will be determined, above all, by the magnitude and location of the bleeding, the mildest case being meningeal irritation, but also causing death.


Signs and tests

An eye exam may show increased pressure within the brain (increased intracranial pressure), including inflammation of the optic nerve ( papilledema ) or bleeding within the retina. The following tests can be used to diagnose a brain aneurysm and determine the cause of bleeding within the brain.

  • Head CT that can identify bleeding and occasionally locate the aneurysm.
  • CSF (cerebrospinal fluid) or spinal tap analysis that can confirm bleeding.
  • Head MRI, which may be an alternative to CT, but is not as sensitive to bleeding within the brain.
  • Cerebral angiographyor conventional angiography of the head with spiral CT scan is used to indicate the location and size of the aneurysm.

An EEG ( electroencephalogram ) may be done if seizures occur.


It is very variable. A brain aneurysm that does not rupture may not cause any symptoms. According to Dr. Frutos, they are usually discovered because they are patients with large headaches or because they are being explored for another problem related to the brain. However, about 25 percent of ruptured brain aneurysms have a fatal outcome within the first 24 hours. Approximately another 25 percent are fatal within 3 months. Of the rest of the people with a ruptured brain aneurysm, more than half suffer from some type of permanent disability.

To locate and determine the intensity of an aneurysm, there are several studies that can be carried out. To corroborate the presence of bleeding, nothing better than a lumbar puncture. But the study may also be focused on brain computed tomography or magnetic resonance imaging, which will confirm both the presence of bleeding and presuppose the location of the ruptured aneurysm. The cerebral angiography is a study focused visualization and exact location as well as its relationship with other neighboring vessels or their morphological characteristics.



The usual treatment admits two main phases: The first, as soon as the patient is accepted in an inpatient service, preferably in an intensive care service, where the general condition of the patient will be taken care of.

In addition, specific medication will be administered to control high blood pressure, avoid spasm or hypoxia, with the intention of mitigating the damage caused by the bleeding and preventing the recurrence of new bleeding, in addition to preparing the patient to surgical or endovascular treatment. Once the diagnosis has been made and the patient has been compensated, the neurosurgeon takes sides, who will decide on conventional open surgery and the placement of a clip, a small metal clasp, that will close the ruptured aneurysm so that it does not bleed again, or the procedure endovascular.

Although catheterization is the least traumatic solution , there are aneurysms that can be solved in this way, and others that must necessarily be solved by conventional surgery with the help of the surgical microscope and micro neurosurgery instruments .


The prognosis varies. Patients who go into a deep coma after an aneurysm ruptures do not recover as well as those with less severe symptoms.

Broken brain aneurysms are usually fatal. Approximately 25% of people die within the first 24 hours and another 25% die within approximately 3 months. Of those who survive, more than half suffer from some form of permanent disability.


  • Increased fluid pressure inside the skull.
  • Loss of movement in one or more parts of the body.
  • Other neurological problems (such as vision changes, trouble speaking, cognitive decline).
  • Permanent loss of sensation in any part of the face or body.
  • Seizures, epilepsy.
  • Stroke.

Situations requiring medical assistance

You should go to the emergency room or call your local emergency number (911 in the United States ) if sudden or severe headaches occur, particularly if the person also has nausea, vomiting, seizures, or other neurological symptoms . Also, it should be called if the person has an unusual headache.


There is no known way to prevent the formation of a brain aneurysm. If discovered early, aneurysms that have not ruptured can be treated before they cause problems. The decision to repair a brain aneurysm that has not ruptured is based on size, where it is located, the patient’s age, and general health. Such decision must be carefully considered given the inherent risks of both the operation and the waiting


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