Brain Aneurysms and AVMs
A cerebral aneurysm is a weakness in the wall of a blood vessel in the brain. Aneurysms can be a congenital defect or can develop later in life from conditions such as hypertensive vascular disease or atherosclerosis.
A burst or ruptured aneurysm allows blood to go into the brain. When the blood supply to part of the brain is reduced or completely blocked, a stroke may occur. The part of the brain deprived of blood dies and can no longer function.
Other problems may follow, including recurrent bleeding, water on the brain (hydrocephalus) and narrowing of the blood vessels (vasospasm). Aneurysms also can enlarge. Hemorrhaging occurs often without warning and is life threatening.
Although it is estimated that about 5-percent of people in North America and Europe have or will develop aneurysms, few actually rupture. Ruptured aneurysms are more common in people in their 50s and 60s.
Arteriovenous malformations or AVMs are abnormal blood vessels in the brain and are a congenital disorder. The cerebrovascular malformations vary greatly from person to person.
AVMs are a tangled web of arteries and arterialized veins. Brain tissue between the vessels is usually abnormal and often scarred from previous tiny hemorrhages of which the person may be unaware or may have thought was a bad headache.
AVMs can occur in many locations throughout the brain and spinal cord and sometimes are detected only when they cause symptoms based on their locations.
Few warning signs precede an aneurysm or AVM until bleeding occurs. Aneurysm symptoms after a rupture may include sudden and severe headache, vision or speech impairment, loss of consciousness, seizures, weakness on one side, numbness or tingling, and nausea and vomiting.
Recurrent headaches can be an indication of a small amount of bleeding in an AVM prior to a serious hemorrhage. Other symptoms include seizures and neurological problems such as paralysis or loss of speech, memory or vision, depending on the location of the AVM. Other symptoms can involve changes in mental capacity.
In addition to physical and neurological examinations, patients can have a scan of the brain to help locate the bleeding or a lumbar puncture to see how much blood has mixed with the cerebrospinal fluid.
An angiogram can pinpoint the aneurysm or AVM. A magnetic resonance image scan or MRI can be used to locate an aneurysm or AVM that has not yet bled.
The patient may require an evaluation of neurologic injury or an electroencephalogram for seizures.
Cerebral aneurysms and AVMs are often emergencies by the time they are discovered. The aim of treatment once a hemorrhage has occurred is to stop the bleeding and damage to the brain and to reduce the risk of recurrence.
The weeks immediately following the hemorrhage are most important since that is the period when complications occur and re-rupture most likely.
Surgeons may be able to repair or clip the ruptured aneurysm to reduce the risk of additional bleeding. They may also repair additional unbroken aneurysms if possible.
If direct surgery is too risky, endovascular surgery may be performed to insert tiny coils or balloons to stop the blood flow. Other treatment includes complete bed rest and medications for headaches, seizures or other problems.
Treatment may include speech, physical and occupational therapy, depending on the neurologic injury.
Research continues to improve radiosurgical techniques so that larger lesions in important areas of the brain can be treated using focused radiation like the Gamma Knife®. This gives hope that previously inoperable tumors and AVMs may be amenable to treatment.
Endovascular treatment continues to be promising. Researchers are looking at new techniques and comparing them with standard surgery.
Wake Forest Baptist Approach
The treatment of brain and spinal arteriovenous malformations is a collaborative effort between the Departments of Neurosurgery and Neuroradiology.
The Brain Arteriovenous Malformation Center has special areas of expertise including surgical treatments such as pre-operative endovascular embolization, image-guided craniotomy and stereotactic radiosurgery, which is done with the Gamma Knife.
This bombards lesions with enough radiation to destroy them, even in critical difficult-to-reach areas of the brain. It is called surgery without a scalpel and requires only 1 treatment of an average of about an hour.
Patients can return to their normal routines within a day of the procedure. It is used to treat brain tumors, AVMs and other problems as well.
The Gamma Knife Center has researchers working on ways to more precisely treat targets in the brain close to critical brain structures. Also, they are working to identify drugs that can sensitize cancerous brain tumor cells to the effects of radiation produced by the Gamma Knife and therefore improve the probability of curing the most malignant brain tumors.
In addition, the Medical Center is one of about 2 dozen centers that are part of the International Hypothermia in Aneurysm Surgery Trial (IHAST), which is funded by the National Institutes of Health. That study is looking at whether cooling a patient’s body temperature can help protect the brain against damage during aneurysm surgery.
Also, the Medical Center is tracking surgery patients who have had a combination of endovascular treatment and surgery to follow their outcomes and results.