Cerebral aneurysm

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 into the subarachnoid space surrounding the brain, causing a subarachnoid hemorrhage[?] resulting in stroke. Rebleeding, hydrocephalus (the excessive accumulation of cerebrospinal fluid), vasospasm[?] (spasm of the blood vessels), or additional aneurysms may also occur. An unruptured cerebral aneurysm has a 1 in 25 chance of bleeding during any given year.

In outlining symptoms of ruptured cerebral aneurysm, it is useful to make use of the Hunt and Hess scale of subarachnoid hemorrhage severity:

• Grade 1: Asymptomatic; or minimal headache and slight nuchal rigidity. Approximate survival rate 70%.
• Grade 2: Moderate to severe headache; nuchal rigidity; no neurologic deficit except cranial nerve palsy. 60%.
• Grade 3: Drowsy; minimal neurologic deficit. 50%.
• Grade 4: Stuporous; moderate to severe hemiparesis; possibly early decerebrate rigidity and vegetative disturbances. 20%.
• Grade 5: Deep coma; decerebrate rigidity; moribund. 10%.

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 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 person’s 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. However, estimates are, that of the 30,000 people per year in the United States who suffer a ruptured aneurysm, only 20% will be alive and well in one year's time. 20% will be alive but disabled, and 60% will have died.

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The base text for this article was taken from the National Institute of Neurological Disorders and Stroke public domain resource at http://www.ninds.nih.gov/health_and_medical/disorders/ceraneur_doc.htm