Aneurysms and Blood Vessel Disorders
A cerebral aneurysm is a weak spot along a blood vessel in the brain that bulges outward. Often described as balloon-like in appearance, aneurysms may bust and bleed into the brain (hemorrhage), potentially causing life-threatening complications.
Even if an aneurysm does not burst, it can cause other problems by putting pressure on nerves or brain tissue. Most cerebral aneurysms occur along a ring of interconnected arteries at the base of the brain known as the circle of Willis.
Types of Aneurysms
There are different types of cerebral aneurysms:
- Saccular is the most common type of brain aneurysm. It develops along weak spots in the wall of an artery.
- Dissecting is a type of aneurysm that forms from tears to the innermost layers of a blood vessel following a traumatic injury or plaque formation.
- Mycotic is a type of aneurysm that is caused by a bacterial infection in the wall of an artery.
- Pseudoaneurysm is the dilatation of an artery that forms when the artery is injured by abrupt, severe trauma.
How common are aneurysms?
About five percent of the population has at least one cerebral aneurysm, and one-third of those people have more than one. Each year, aneurysms rupture in 10 to 20 per 100,000 people.
Who gets aneurysms?
Brain aneurysms can occur in anyone at any age, but they are more common in adults than in children and slightly more common in women than in men. They also occur more often in people with certain genetic diseases and circulatory disorders, such as arteriovenous malformations (snarled tangles of blood vessels in the brain which disrupt blood flow).
Other causes of aneurysms include:
- Head trauma
- High blood pressure
- Atherosclerosis and other diseases of the vascular system
- Cigarette smoking
- Drug abuse
How are aneurysms diagnosed?
Most cerebral aneurysms go unnoticed until they rupture or are detected by imaging tests done for other reasons.
The following tests may be used to diagnose an aneurysm:
- CT scan
- MRI scan
- Lumbar puncture (spinal tap)
Brain aneurysms usually do not cause symptoms until they either become very large or burst. Most aneurysms are found when they rupture and bleed into the space between the skull and the brain, a serious condition called subarachnoid hemorrhage.
Symptoms of a brain aneurysm pressing on surrounding tissue and nerves may include:
- Pain above and behind the eye
- Numbness, weakness, or paralysis on one side of the face
- Dilated pupils
- Vision changes
Symptoms of a ruptured aneurysm may include:
- Sudden, severe headache
- Double vision
- Drooping eyelid
- Stiff neck
- Sensitivity to light
- Loss of consciousness, including coma
Subarachnoid hemorrhage can cause serious complications, including:
- Hydrocephalus is an abnormal buildup of cerebrospinal fluid in the skull that puts pressure on brain tissue.
- Vasospasm is a constrictive narrowing of blood vessels, which reduces the amount of blood flow to the brain and can cause stroke or tissue damage.
If you are experiencing symptoms of an aneurysm, contact a medical professional.
Not all aneurysms rupture. Small aneurysms may be monitored for growth and symptom onset. When deciding whether or not to treat an unruptured aneurysm, your doctor will consider the type, size, and location of the aneurysm; your health, age, and medical history; and the risks associated with treatment.
Treatments for cerebral aneurysms include:
- Microvascular clipping is a surgical procedure that involves cutting off blood flow to the aneurysm. Your neurosurgeon will open up part of your skull and place a clip on the neck of the aneurysm to halt its blood supply.
- Occlusion is a procedure where your neurosurgeon will clamp off the entire artery leading to the aneurysm. This surgery is often performed when an aneurysm has damaged an artery. It may be accompanied by a bypass, in which a small blood vessel is surgically grafted to the brain artery to reroute blood flow away from the damaged section of the artery.
- Endovascular embolization is a treatment where a catheter is inserted into a major artery and threaded through the body to the site of the aneurysm. Detachable coils are passed through the catheter and then released into the aneurysm. The coils fill the aneurysm, block it from circulation, and cause the blood to clot, decreasing the chances of rupture or other future complications.
- Date of last review: November 26, 2016
- Author: Robert Spetzler, MD