An aneurysm forms when the walls of a blood vessel weaken and balloon out. It can form as a sack-like appendage, a one-sided bulge or the enlargement of an entire brain artery. In children, the most common identifiable causes of aneurysms are severe head trauma and infection. In adults the condition is more likely to occur in blood vessels weakened by atherosclerosis. In any case, the risk of an aneurysm is that the artery wall will fail and blood will spill into the brain, increasing pressure inside the skull and depriving the brain of oxygen.
Cerebral aneurysms are very rare in children and usually cause few symptoms until they burst. If they do, symptoms can range from severe headache with neurological disturbances to complete loss of consciousness. Emergency surgery is usually required.
The surgeon will probably recommend one of two surgeries. Clipping is exactly what it sounds like. The neurosurgeon applies a small metal clip at the base of the aneurysm, closing off the blood flow to it. In embolization, the surgeon or interventional radiologist feeds a tiny tube through the arteries to the site of the aneurysm and injects a material that causes the blood in the artery to clot, closing off the aneurysm. The outlook for these patients depends mainly on how much damage may have been done before the patient gets to surgery, whether the treatment itself blocks off important blood vessels, or whether spasm of the adjacent blood vessels causes a stroke to occur.