A cerebral aneurysm is the dilation, bulging or ballooning out of part of the wall of a vein or artery in the brain. The disorder may result from congenital defects or from other conditions such as high blood pressure, atherosclerosis (the build-up of fatty deposits in the arteries), or head trauma. Cerebral aneurysms can occur at any age, although they are more common in adults than in children and are slightly more common in women than in men. The signs and symptoms of an unruptured cerebral aneurysm will partly depend on its size and rate of growth. For example, a small, unchanging aneurysm will generally produce no symptoms, whereas a larger aneurysm that is steadily growing may produce symptoms such as loss of feeling in the face or problems with the eyes. Immediately before an aneurysm ruptures, an individual may experience such symptoms as a sudden and usually severe headache, nausea, vision impairment, vomiting, and loss of consciousness. Rupture of a cerebral aneurysm usually results in bleeding in the brain, causing a hemhorrhagic stroke. Or blood can leak into the area surrounding the brain and develop into an intracranial hematoma (a blood clot within the skull). Rebleeding, hydrocephalus (the excessive accumulation of cerebrospinal fluid), vasospasm (spasm of the blood vessels), or additional aneurysms may also occur.
Emergency treatment for individuals with a ruptured cerebral aneurysm generally includes restoring deteriorating respiration and reducing intracranial pressure. Surgery is usually performed within the first 3 days to clip the ruptured aneurysm and to reduce the risk of rebleeding. When aneurysms are discovered before rupture occurs, microcoil thrombosis (see illustration) or balloon embolization may be performed on patients for whom surgery is considered too risky. During these procedures, a thin, hollow tube (catheter) is inserted through an artery to travel up to the brain. Once the catheter reaches the aneurysm, tiny balloons or coils are used to block blood flow through the aneurysm. Other treatments may include bed rest, drug therapy, or hypertensive-hypervolemic therapy (which elevates blood pressure, increases blood volume, and thins the blood) to drive blood flow through and around blocked arteries and control vasospasm.
The prognosis for a patient with a ruptured cerebral aneurysm depends on the extent and location of the aneurysm, the personis age, general health, and neurological condition. Some individuals with a ruptured cerebral aneurysm die from the initial bleeding. Other individuals with cerebral aneurysm recover with little or no neurological deficit. Early diagnosis and treatment are important.
National Institute for Neurological Disorders and Stroke
Reviewed: March 2003
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