A cerebral aneurysm is an abnormal swelling of a blood vessel wall inside the brain.
A cerebral aneurysm is an area where the elastic layer in the wall of a a blood vessel in the brain has weakened. As a result, the vessel wall balloons out. Aneurysms usually form where arteries branch, because the vessel wall is weaker at this point Over time, the aneurysm may balloon and thin the wall so much that it ruptures.
Many aneurysms cause no symptoms until they get quite large or rupture. Many times, cerebral aneurysms are found incidentally during the work-up for another condition. However, a sudden, extremely severe "thunder-clap" headache is the telltale symptom that an aneurysm has ruptured.
The individual might have a sudden loss of consciousness followed by a brief lucid interval. Occasionally, the individual never regains consciousness and dies within minutes. However usually, the period of lucidity is followed by drowsiness and is accompanied by neck pain.
Before an aneurysm ruptures, it may leak (an event called a "sentinel bleed") causing headache days or weeks prior to the actual rupture. Once the aneurysm ruptures, blood is pumped out of the vessel at a high pressure into a space surrounding the brain. The blood then presses on the brain causing brain damage, and in many cases death before the person can reach the hospital.
Aneurysms are often congenital, that is, present from birth. Other times, the development of a cerebral aneurysm may result from a combination of factors including high blood pressure, smoking, and arteriosclerosis (aka hardening of the arteries).
As the person gets older, aneurysms grow.. An individual with a family history of cerebral aneurysm is at a slightly higher risk, and debate continues regarding whether it is useful to screen individuals who have a close relative with this disorder.
Although rare, sometimes an aneurysm can be caused by sepsis, an infection in the blood. The bacteria can lodge in the vessel wall and weaken it. A condition known as polycystic kidney disease is associated with an increased risk of cerebral aneurysm, as is Ehlers-Danlos syndrome, an inherited disorder of abnormal collagen production.
Currently, studies suggest that risk of a cerebral aneurysm may be reduced by carefully controlling high blood pressure, avoiding smoking tobacco, and following a diet low in cholesterol. In addition, screening family members of an individual with cerebral aneurysm for this disorder may be appropriate under some circumstances.
Usually if discovered prior to rupture, a cerebral aneurysm is an incidental finding on MRI or MRA (an MRI study of the arteries of the brain) which was done to evaluate an unrelated problem.
Occasionally, an aneurysm is large enough or is in a place that will cause symptoms such as headache, visual disturbances, or symptoms referable to the pituitary gland. In this instance, the neurological examination may be abnormal, leading the clinician to order a brain MRI and/or MRA, on which the aneurysm can be seen.
There may be no long-term effects for an individual with an unruptured cerebral aneurysm. However, rupture of a cerebral aneurysm is a critical event often resulting in death the person can reach the hospital. The overall risk of death is 45% within a month after the rupture, with half of the survivors having significant brain damage.
A cerebral aneurysm poses no risk to others.
The best treatment for an aneurysm varies from person to person. Surgery to repair the aneurysm is quite risky in itself. The American Heart Association, called the AHA, has issued guidelines for treatment of unruptured aneurysms. The AHA guidelines advise the healthcare professional to look at three factors when choosing the treatment plan: the size of the aneurysmthe person's agethe person's life expectancy
For older persons with an unruptured aneurysm, the AHA guidelines recommend to wait and watch. The aneurysm can be monitored with regular cranial CT scans or cranial MRIs.
Younger people are usually good candidates for surgery. A craniotomy is a type of brain surgery that is used to repair an aneurysm. With the most common type, a metal clip is used to close off the aneurysm at its base. Medicines may be used to control high blood pressure or to treat problems with blood clotting.
Side effects vary, depending on the treatment chosen. Medicines can cause allergic reactions and problems with blood clotting. Surgery can be complicated by bleeding, infection, or a reaction to the anesthesia. Even if the person survives surgery, he or she can sometimes be left with permanent disabilities resulting from a brain injury incurred during surgery.
A person with significant disabilities may need rehabilitation therapy on a long-term basis. This may include speech therapy, occupational therapy, and physical therapy.
If the aneurysm was successfully removed surgically, a person may not need any more monitoring. However, someone who has major disabilities either from surgery or after surviving the rupture of an aneurysm may need frequent visits to the healthcare professional. Any new or worsening symptoms should be reported.