Dismiss Modal

Definition

Arteriovenous Malformation (AVM)

Choose a preferred language

You have an arteriovenous malformation (AVM). An AVM is an abnormal tangle of blood vessels that causes irregular connections between arteries and veins in the brain. Some AVMs never burst (rupture). But some things can lead to a rupture. Some of these factors are known, such as a rise in blood pressure. And some factors are not known.

If you have an AVM, you were likely born with it. Many people don't know they have AVM until a problem develops. Signs of an AVM include:

  • Bad headaches

  • Sudden or gradual paralysis or loss of sensation

  • Blurred or double vision

  • Jerking movements that you can't control (seizures)


Understanding an AVM

The brain controls the body. You can move and feel because of the brain. And it is the brain that makes you able to think, show emotions, remember, and make judgments. An AVM can damage the brain and put the rest of the body in danger.


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.

Side view of head and brain.


A problem with blood flow

An AVM is a tangle of blood vessels. It can cause pressure to build up in the blood vessel and prevent normal blood flow. If the pressure becomes too great or the wall of the AVM vessel weakens, a blood vessel can burst and blood can leak or spurt into the brain. This can damage parts of the brain that control vital body functions, such as sight, sensation, language, critical thinking, and movements. In some cases, problems caused by an AVM can even lead to death. The high blood flow in an AVM can also shunt the oxygen from the arteries directly to the veins, bypassing the brain capillaries. This shunting can lead to strokes. AVM can be treated based on the type, symptoms, and cause.

Closeup view of arteriovenous malformation (AVM) in the brain.

© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Find a doctor that's right for you.

From routine check-ups to groundbreaking treatments and beyond, Crestner Health is here to help you live your healthiest life.

Search our doctors
Related Articles
Read article
Brain Health
Reasons for a Craniotomy

Learn about the problems that may need a craniotomy.

Read article
Brain Health
Hemorrhagic Stroke: Subarachnoid Hemorrhage

A hemorrhagic stroke happens when a blood vessel in the brain ruptures or leaks. A blood vessel on the surface of the brain bursts (hemorrhages). This spills blood into the surrounding tissue. This type of stroke often happens suddenly, with little warning.

Read article
Brain Health
Anatomy of the Brain

Learn about the brain, its parts, each part's functions, and how the brain is protected.

Read article
Brain Health
Neurology

Neurology is the branch of medicine that is concerned with the study and treatment of disorders of the nervous system.