Arteriovenous malformations (AVMs) are defects of the circulatory system that are generally believed to arise during embryonic or fetal development or soon after birth. Although AVMs can develop in many different sites, those located in the brain or spinal cord can have especially widespread effects on the body. Most people with neurological AVMs experience few, if any, significant symptoms. The malformations tend to be discovered only incidentally, usually either at autopsy or during treatment for an unrelated disorder. But for about 12 percent of the affected population (about 36,000 of the estimated 300,000 Americans with AVMs), these abnormalities cause symptoms that vary greatly in severity. Seizures and headaches are the most generalized symptoms. AVMs also can cause a wide range of more specific neurological symptoms that vary from person to person, depending primarily upon the location of the AVM. Such symptoms may include muscle weakness or paralysis, loss of coordination, difficulties carrying out tasks that require planning, dizziness, visual disturbances, problems using or understanding language, abnormal sensations (such as numbness, tingling, or spontaneous pain), memory deficits, mental confusion, hallucinations, or dementia.
Medication can often alleviate general symptoms such as headache, back pain, and seizures caused by AVMs and other vascular
lesions. However, the definitive treatment for AVMs is either surgery or focused irradiation therapy. The decision to perform surgery on any individual with an AVM requires a careful consideration of possible benefits versus
risks. Because so many variables are involved in treating AVMs, doctors must assess the danger posed to individual patients largely
on a case-by-case basis.
The greatest potential danger posed by AVMs is hemorrhage. Researchers believe that each year between 2 and 4 percent of all
AVMs hemorrhage. Most episodes of bleeding remain undetected at the time they occur because they are not severe enough to
cause significant neurological damage. But massive, even fatal, bleeding episodes do occur. Whenever an AVM is detected, the
individual should be carefully and consistently monitored for any signs of instability that may indicate an increased risk
of hemorrhage.
The National Institute of Neurological Disorders and Stroke (NINDS) conducts research related to AVMs in its laboratories
at the National Institutes of Health (NIH) and also supports additional AVM research through grants to major medical institutions
across the country. A group of NINDS-sponsored researchers is currently studying large populations of patients with AVMs to formulate criteria that
will allow doctors to predict more accurately the risk of hemorrhage in individual patients. Other scientists are seeking to refine the techniques now available to treat AVMs. Several ongoing studies are devoted to developing new noninvasive neuroimaging technologies to increase the effectiveness
and safety of AVM surgery.
National Organization for Rare Disorders (NORD) P.O. Box 1968 (55 Kenosia Avenue) Danbury, CT 06813-1968 orphan@rarediseases.org http://www.rarediseases.org Tel: 203-744-0100 Voice Mail 800-999-NORD (6673) Fax: 203-798-2291 |
International RadioSurgery Association 3002 N. Second Street Harrisburg, PA 17110 office1@irsa.org http://www.irsa.org Tel: 717-260-9808 Fax: 717-260-9809 |
Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892
NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.
All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.
Last updated March 04, 2009