Arteriovenous Malformation (AVM)
An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels. This defect, which can occur anywhere in the central nervous system, causes blood to flow directly from arteries to veins through an abnormal passageway called a fistula instead of through capillaries. Generally speaking, there are three ways an AVM can damage the brain or spinal cord:
- the amount of oxygen delivered to brain and spinal tissues is reduced, causing them to deteriorate and die
- arteries and veins in an AVM can rupture, causing bleeding in the brain or spinal cord (hemorrhage)
- an AVM can compress or displace parts of the brain or spinal cord
How common are arteriovenous malformations?
An estimated 300,000 Americans are affected by arteriovenous malformations of the brain and spinal cord (neurological AVMs), but only about 12 percent of the affected population will have symptoms.
Who gets arteriovenous malformations?
Arteriovenous malformations are equally common among men and woman of all races and ethnicities. They are believed to be congenital (existing at birth), but they can enlarge over time and cause symptoms at any age.
Pregnancy can sometimes cause a sudden onset or worsening of symptoms because of cardiovascular changes, such as increases in blood volume and blood pressure.
How are arteriovenous malformations diagnosed?
Most arteriovenous malformations are detected through diagnostic imaging, such as a CT or MRI scan. Angiography, an imaging technique that involves the injection of a special dye, may be used to get a better look at the AVM.
Because most people with AVMs experience few symptoms, these abnormalities are often discovered during treatment for an unrelated disorder.
Symptoms can vary depending on the severity and location of the arteriovenous malformation, or they may never appear at all.
Symptoms of a neurological AVM may include:
- muscle weakness or paralysis
- problems with balance and coordination (ataxia)
- pain or unusual sensations throughout your body, such as tingling or numbness
- visual disturbances such as loss of part of the visual field
- inability to control eye movement
- problems understanding language (aphasia)
- memory deficits
- mental confusion, hallucinations, or dementia
AVMs share symptoms with other conditions. Imaging tests by a medical professional are needed to diagnose an AVM.
Treatment depends on the size and location of the arteriovenous malformation. Your doctor may recommend one or a combination of the following treatments:
- Conventional surgery – The AVM is resected using microsurgical techniques.
- Endovascular embolization – In this minimally invasive alternative to surgery, a catheter is guided through the network of arteries until the tip reaches the site of the AVM. Various branches of the AVM are then plugged with a material such as glue or a metal coil.
- Radiosurgery – In this noninvasive procedure, focused beams of radiation are used to destroy the AVM. Gamma Knife and Cyberknife radiosurgeries are offered at Barrow.
- Date of last review: September 10, 2015
- Author: Felipe Albuquerque, MD