Aneurysm Information
(from the US National Library of Medicine)

What is an aneurysm?

An abnormal widening or ballooning of a portion of a blood vessel. The blood vessel wall becomes weaker in this location. There are several types of aneurysms: abdominal aortic aneurysm, aortic dissection, thoracic aortic aneurysm and cerebral aneurysm.

Aneurysms in the brain occur when there is a weakened area in the wall of a blood vessel. They may occur as a congenital defect or may develop later in life.

A saccular aneurysm (berry aneurysm) is usually small in size. The aneurysm resembles a sack of blood attached to one side of the blood vessel by a narrow neck. These are more common in adults. Multiple berry aneurysms are not unusual. They occur in any part of the brain but are most often seen in the large arteries at the base of the brain.

Berry aneurysm is also associated with polycystic kidney disease and coarctation of the aorta. Rarely, berry aneurysm can run in families. Other types of cerebral aneurysm may involve widening (dilatation) of the entire circumference of the blood vessel in an area, or may appear as a ballooning out of part of a blood vessel.

These types of aneurysms can occur in any part of the brain. Symptoms usually do not appear until complications develop. Bleeding is the most common cause of symptoms, with subarachnoid hemorrhage the usual type of bleed.

Weakness, numbness, or other loss of nerve function (neurologic deficits) may occur because of pressure from the aneurysm on adjacent brain tissue or because of reduced blood flow caused by a spasm of other blood vessels near a ruptured aneurysm.

It is estimated that 5 percent of the population has some type of aneurysm. However, the incidence of ruptured aneurysm is approximately 4 out of 100,000 people per year.

Prevention

There is no known way to prevent formation of a cerebral aneurysm. If discovered in time, unruptured aneurysms can be treated before causing problems.

Symptoms of a bleed may include:

• sudden occurrence of a headache (severe or described as "the worst in patient's experience")
• headaches with nausea or vomiting stiff neck (occasionally)
• muscle weakness, difficulty moving any part of the body
• numbness or decreased sensation in any part of the body
• vision changes eye lid drooping changes in mental status, the person may be lethargic, sleepy, or stuporous seizures
• slow, sluggish, lethargic movement speech impairment
• irritability or poor temper control

Treatment

Because symptoms often do not appear until bleeding occurs, cerebral aneurysm may be an emergency condition when it is discovered. The goal of treatment is to control symptoms and prevent further bleeding. Surgery is the primary treatment for cerebral aneurysm. The base of the aneurysm is closed off with clamps, sutures, or other methods that prevent blood flow through the aneurysm.

If surgery is not feasible because of the location or size of the aneurysm or the condition of the person, medical treatment is similar to treatment for subarachnoid hemorrhage. This may include restricting activity (often complete bedrest is advised), treating symptoms such as headache, and prescribing preventive (prophylactic) use of antiseizure medications.

Prognosis

The outcome varies. A cerebral aneurysm that does not rupture may not cause any symptoms. However, about 25% of ruptured cerebral aneurysms are fatal within 24 hours. Another 25% are fatal within about 3 months. Of the remaining people with ruptured cerebral aneurysm, more than one-half will have some sort of permanent disability.

Call your health care provider

Go to the emergency room or call the local emergency number (such as 911) if sudden or severe headache occurs, particularly if accompanied by vomiting, seizures, or other symptoms of cerebral aneurysm.

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