Brain Aneurysm

Aneurysm, Brain Health Summary
An aneurysm is a weakened area of a blood vessel that causes ballooning or bulging. Rapid diagnosis and treatment of an aneurysm can help prevent serious consequences.
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Brain Aneurysm Overview

Brain aneurysms occur because of weakness in the wall of an artery in the brain that allows a small bulging or ballooning.

An aneurysm by itself does not cause symptoms and may be found in up to 10% of the population.

Symptoms occur when blood leaks from the artery into the subarachnoid space (the area that surrounds the brain and spinal cord that is filled with cerebrospinal fluid) or into adjacent brain tissue and causes inflammation or even brain tissue compression. Severe headache, stiff neck, and vomiting most commonly occur.

Usually, there is a sentinel or "warning" headache with a small leak of blood. This is a sign that one should seek help and have symptoms evaluated. The second bleed tends to be more catastrophic, causing significant brain damage.

The diagnosis of brain aneurysm and subarachnoid hemorrhage includes a high index of suspicion by the physician. A CT scan of the brain is the first test and is helpful 95% of the time. A lumbar puncture may be performed to look for bleeding if the CT scan is normal and an aneurysm has not been ruled out.

Treatment for a ruptured aneurysm depends upon the patient's presentation and potential for recovery. Neurosurgery to place a clip across the aneurysm or interventional radiology to place platinum coils into the aneurysm may be appropriate options.

Brain Aneurysm Causes

There are four blood vessels that supply the brain with blood, two carotid arteries and two vertebral arteries. They come together at the base of the brain to form the Circle of Willis and from there smaller blood vessels branch out to send blood to all areas of the brain.

Picture of brain aneurysm
Picture of brain aneurysm

Weak spots may exist where blood vessels come together or split. These areas are at risk of becoming damaged and, over time, a section of the blood vessel wall can balloon out and form a small sac or bubble just like an inner tube with a weak patch. This weakened area is called an aneurysm. Aneurysms usually do not produce symptoms, except when they leak blood into the subarachnoid space (the area that contains cerebrospinal fluid) or into adjacent brain tissue.

Aneurysms may be caused by a variety of factors. They may be congenital, meaning they were present at birth. They may be hereditary. Poorly controlled high blood pressure (hypertension) may be a potential cause, with that increased blood pressure exerting force on the weakened artery wall. Since aneurysms are often located at blood vessel junctions, it may be that blood flow turbulence -- similar to water turbulence that occurs where rivers come together -- may be a contributing factor. Ultimately, the cause of an aneurysm may be multifactorial.

There are a variety of medical conditions associated with brain aneurysms that may involve abnormalities of blood vessel walls including Marfan syndrome, Ehlers-Danlos syndrome, coarctation of the aorta, and arteriovenous malformations. Systemic lupus erythematosus, collagen vascular diseases, and sickle disease are also associated with an increased risk of brain aneurysms.

Medically Reviewed by a Doctor on 8/27/2014

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