(AVM; Arteriovenous Malformations of the Brain; AMB)
Pronounced: Ar-teer-ee-o-vee-nus Mal-form-ay-shonsEn Español (Spanish Version)
Arteriovenous malformations (AVM) of the brain and spinal cord affect approximately 300,000 Americans. They are tangles of abnormal blood vessels. Arteriovenous malformations can form wherever arteries and veins exist. However, the ones that form in the brain or spinal cord can have especially serious effects.
Blood flows through arteries, bringing oxygen from the heart to the brain. The blood then enters smaller blood vessels that slow the blood flow and allow oxygen to be delivered to the surrounding tissue. Finally, the veins carry the oxygen depleted blood away from the brain to the heart and lungs to pick up more oxygen.
Arteries in arteriovenous malformations don’t follow this pattern. They dump blood directly into veins through a channel called a fistula, an abnormal tube-like opening. The blood flow through this fistula is extremely fast. Complications from this include:
Arteriovenous Malformation in the Brain
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Two to four percent of all arteriovenous malformations hemorrhage or bleed. The damage caused by the bleeding depends on where the arteriovenous malformation is located. If the hemorrhage is in the brain, brain tissue can be damaged. It may be temporary or permanent damage.
Arteriovenous malformations can seriously damage the brain and the spinal cord by:
Complications of arteriovenous malformations include strokes (blood supply and oxygen are totally cut off from the brain), hydrocephalus (excessive build-up of fluid within the brain), spinal cord injury (possibly causing paralysis), and death.
If you suspect you have this condition, contact your doctor immediately.
The cause of arteriovenous malformations is unknown. However, researchers believe that they occur as a fetus is developing and the arteriovenous malformations are present when you are born. However, they may develop and change over time as well.
A risk factor is something that increases your chance of getting a disease or condition.
If you have any of these risk factors, tell your doctor:
There are a number of symptoms that you may experience if you have an arteriovenous malformation. Symptoms vary from person to person. They also depend on the location of the arteriovenous malformation in your body.
If you experience any of these symptoms, do not assume it is due to arteriovenous malformations. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician.
Children under the age of two may have different symptoms, including:
Your doctor will ask about your symptoms and medical history. A physical exam will be done.
Your doctor will need more information to make an evaluation. To get a more comprehensive understanding of your condition, your doctor may order some tests. Tests may include the following:
Your doctor will most likely refer you to a specialist for further examination and treatment. There are a number of specialists who focus on arteriovenous malformation, including neurologists, neurosurgeons, and neuroradiologists.
The goal of treatment is to prevent hemorrhaging, which can lead to strokes. Your doctor will need to determine if your arteriovenous malformation has bled, if it is not too large, and if it is located in an area that can be easily reached and treated.
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
Medication may be taken to ease the symptoms you may be experiencing, such as headache, back pain, and seizures. This, however, does not eliminate the arteriovenous malformation.
You must work with your doctor to decide whether you’d like to go ahead with surgery to treat your arteriovenous malformation or not. Leaving an arteriovenous malformation untreated may lead to serious complications. However, there is always a risk of nervous system damage with surgery.
There are three different types of surgery available and the choice of which one will depend on the size and location of the arteriovenous malformation. The types of surgery include:
This standard surgery involves doing surgery on the area of the brain or spinal cord where the arteriovenous malformation, including the fistula, is located. This procedure is the most thorough treatment for arteriovenous malformations.
Endovascular embolization is often used for arteriovenous malformations that are located deeper within the brain. Regular surgery cannot be used for risk of damage to the surrounding tissue in the brain or spinal cord.
A surgeon will guide a catheter through your arteries until it reaches the arteriovenous malformation. Then a substance will be inserted to plug the fistula. This procedure does not destroy the arteriovenous malformation but it does reduce the blood flow to the arteriovenous malformation and make surgery safer.
This procedure uses a beam of highly concentrated radiation focused directly on the arteriovenous malformation. The radiation damages the walls of the blood vessels leading to the arteriovenous malformation. This procedure does not always totally destroy the arteriovenous malformation, especially if it is very large.
Sometimes, arteriovenous malformations are best left alone based on their size and location. It is best to speak with your physician about your decision.
There is no way to prevent an arteriovenous malformation. However, to help reduce your chances of hemorrhaging, take the following steps:
American Stroke Association
National Institute of Neurological Disorders and Stroke (NINDS)
BC Health Guide
The Toronto Brain Vascular Malformation Study Group
About arteriovenous malformation. Mayo Clinic website. Available at: http://www.mayoclinic.org/arteriovenous-malformation/aboutavm.html . Accessed August 16, 2005.
Arteriovenous malformations and other vascular lesions of the central nervous system fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/avms . Accessed August 16, 2005.
Cerebrovascular Imaging and Intervention Committee of the American Heart Association Cardiovascular Council. What is an arteriovenous malformation (AVM)? American Stroke Association website. Available at: http://www.americanheart.org/downloadable/stroke/1095279678689 . Accessed August 16, 2005.
Choi JH, Mohr JP. Brain arteriovenous malformations in adults. Lancet Neurology . 2005; 4(5):299-308.
Geibprasert, et al. Radiologic assessment of brain arteriovenous malformations: what clinicans need to know. Radiographics . 2010;30(2):483-501.
Ogilvy CS, Stieg PE, Awad I, et al. Recommendations for the management of intracranial arteriovenous malformation: a statement for healthcare professionals from a special writing group of the Stoke Council, American Stroke Association. Stroke . 2001;32:1458.
Treatment of arteriovenous malformation. Mayo Clinic website. Available at: http://www.mayoclinic.org/arteriovenous-malformation/ . Accessed August 16, 2005.
Last reviewed February 2012 by Marjorie Bunch, MD
Last updated Updated: 02/28/2012
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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