Definition and Overview
Aneurysms affect one in fifteen Americans in their lifetime. Brain aneurysms are often not discovered until they rupture, and then the main goal is to stop the flow of blood and minimize the damage to the body.
A brain aneurysm is an expansion of an artery or vein that surrounds the brain. These dilated areas can continue to grow, and may eventually break. They are more common in women than in men, and tend to affect older people, age 35-60, rather than younger people.
A small aneurysm can produce no signs or symptoms, but as it grows it can start to press on nerves or other brain tissue. This pressure can produce neurological symptoms such as a droopy eyelid or double vision. Signs that the aneurysm may have ruptured can include a stiff neck, nausea, vomiting, numbness, vision or eye changes, confusion, seizures, speech problems, or intense headache. If an aneurysm ruptures it is a medical emergency and the person must be taken to a hospital. Many things can cause the weakening in the wall of the artery. They can include an infection that affects the vessels, trauma to the vessels, genetic predisposition, and problems with the kidney or the aorta.
Aneurysms can be classified with respect to their severity. They can be classified based severity ranging from something that the patient would not yet notice or have any problems with, to something that will profoundly affect the patient placing them in a coma or having severe bleeding from the rupture.
In the event that the aneurysm ruptures emergency medical care is required to restore blood flow to the brain. Neurosurgeons will perform a procedure called clipping the aneurysm in which a metal clip is secured around the weak point. This will usually stop the bleeding and relieve the immediate crisis. Asymptomatic aneurysms can be clipped as well if the doctors decide that the size or growth of the weakened wall is profound enough. A potential problem of having an aneurysm rupture is that it can promote something called vasospasm several weeks later, in which the affected vessels can spasm resulting in a stroke. Thus it is important to carefully monitor the aneurysm after any major event.
The overall prognosis of someone suffering from an aneurysm depends in large part upon the patient. One must consider age, other medical problems, and the site and extent of the aneurysm. The less severe more stable aneurysms will generally have a better prognosis than larger more severe ones. About 25% percent of people who suffer a ruptured aneurysm will die within one day of the event. Another 25% will die within three months of the event. Of those who live past this time half or more of them will suffer some sort of permanent disability. It is important to recognize the rupture and to act quickly to restore blood flow to the brain thereby preventing the types of problems that will follow.
A common location of cerebral aneurysms are the Circle of Willis, which is a collection of vessels that feed blood to the brain and form a circular structure at the base of the brain. The Circle of Willis allows for mixing of blood that travels up the right and left carotid arteries. Most aneurysms involve the branches of the carotid artery as they leave or travel around the circle.