Arteriovenous Malformation (AVM)

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)

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.

Blood vessels carry blood throughout the 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.

Pressure builds when blood tries to flow through tangled vessels.