Arteriovenous Malformation (AVM)

You have been told that you have an arteriovenous malformation (AVM). An AVM is an abnormal tangle of blood vessels within the brain. Although some AVMs never rupture, both known factors (such as an increase in blood pressure) and unknown factors can lead to rupture. If you have an AVM, you were probably born with it. Most people do not know they have one until a problem happens. Signs of an AVM include headaches, sudden or progressive paralysis or loss of sensation, blurred or double vision and seizures (jerking movements that are out of your control).

Understanding an AVM

The brain controls the body. You can move and feel because of the brain. The brain gives you the ability to think, show emotions, remember and make judgments. An AVM can damage the brain and put the rest of the body in danger.

Blood vessels carry blood throughout the brain.

Inside the skull

Under the scalp and the skull, a tough membrane (called the dura) surrounds the brain. Beneath the dura, cerebrospinal fluid (CSF) cushions the brain. Blood vessels carry nutrients and oxygen-rich blood throughout the brain.

A problem with blood flow

Pressure builds when blood tries to flow through tangled vessels.

An AVM is a tangle of blood vessels. Normally, blood from arteries flow into a bed of smaller vessels called capillaries where oxygen and nutrient delivery occurs, then flows into veins to go back to the heart to stock up on more oxygen. In an AVM, blood from arteries bypass capillaries and flow directly into veins. This shunting of blood from arteries into veins can lead to decreased delivery of oxygen to brain tissue, causing a stroke. This abnormal flow of blood can also lead to a buildup of pressure inside the blood vessels, causing a blood vessel to burst and leak blood into the brain. This can damage parts of the brain that control vital body functions such as sight, sensation, movements, language and critical thinking. In some cases, problems caused by a ruptured AVM can even lead to death. However, an AVM can be treated.