Diseases & Conditions
Aneurisms can damge the brain
An aneurism is a dilation, or swelling, of a blood vessel (where part of the vein or artery inflates like a balloon).
The wall of the aneurism stretches and is thinner and weaker than the rest of the artery wall.
Because of its likelihood to burst, it poses a serious risk to health.
Rupture of an aneurism in the brain can cause stroke.
What happens when an aneurism ruptures?
When a cerebral aneurism ruptures, it usually bleeds into the area surrounding the brain (subarachnoid space) to cause a subarachnoid hemorrhage (SAH).
This type of hemorrhage usually causes a sudden and severe headache. In severe cases it can lead to a coma or death.
It may also cause:
Nausea and vomiting
Problems with vision
Loss of consciousness
SAH can itself lead to a condition called vasospasm - the abnormal constriction of arteries in the brain.
Vasoplasm usually occurs a week or two after post-haemorrhage surgery.
It can cause strokes or other neurological damage, often more severe than the original haemorrhage.
Less commonly, an aneurism can rupture and bleed into the brain itself (intracerebral hemorrhage) which can produce a variety of symptoms depending of the size and location of the hemorrhage.
How are they discovered?
Unruptured cerebral aneurisms may be discovered when they cause neurological symptoms.
These depend on the location and size of the aneurism but can include headaches, double vision, and trouble walking.
Sometimes aneurisms are also found when a head CT or MRI scan, or angiogram is performed for some other reason.
The diagnosis of a cerebral aneurism is usually confirmed with an angiogram.
This entails taking X-rays of blood vessels in the brain.
CT and MRI scanning are now also used to help diagnose aneurisms, but an angiogram usually provides the most detail of an aneurism's size and location.
How are they treated?
For unruptured aneurisms, the aim is to prevent them from bursting or growing.
For ruptured aneurisms, the aim is to prevent further bleeding, and to prevent or limit vasospasm.
Most cerebral aneurisms can be treated with surgery.
This usually involves placing a small metallic clip across the base of the aneurism to protect the weak abnormal aneurism wall from blood flow and reduce the risk of rupture.
At the same time the normal artery wall is reconstructed to maintain blood flow to the brain.
Other treatments include threading a catheter from an artery in the leg up to the aneurism, and under x-ray guidance placing a metal coil into the aneurism.
After applying an electric current, the blood in the aneurism clots and fills the aneurism.
What causes aneurisms?
Aneurisms can be caused by a number of factors.
Very often, aneurisms develop from a weakening in the structural layer of an artery.
Hypertension (high blood pressure) and atherosclerosis (furring of the artery walls) can promote aneurism growth and rupture.
Certain infections of the blood can also cause aneurism.