An arteriovenous malformation (AVM) is an abnormal cluster of blood
vessels connecting arteries and veins in the brain or spine. It
affects less than one percent of the population.
An AVM disrupts the normal exchange of blood between arteries and
veins. This is a serious problem because veins are thin-walled vessels
that cannot accept high-pressure blood flow for extended periods. The
result is that AVMs can rupture and bleed into the brain. This can
cause devastating neurological symptoms or even death.
Symptoms of AVM
Some AVMs are asymptomatic (do not cause symptoms) and will never
even be diagnosed. However, for those individuals who do have
AVM-related symptoms, the symptoms can help identify where the AVM is located:
Changes in eyesight: The AVM may be in one of the brain's
Weakness on one side of the body: The AVM may be located in a
part of the brain that controls motor skills.
The most common symptom for individuals with an AVM is brain
hemorrhage, which may cause:
symptoms, such as weakness and difficulty with speaking or
Impaired intellectual functions in short or
What Causes AVM?
AVMs can occur in many locations throughout the brain and spine.
There is no known specific cause for most AVMs.
Most people who have AVMs are born with them.
are not thought to be hereditary.
AVMs can sometimes
develop after a head or spine trauma.
Many times, doctors find AVMs after a brain scan for another health
issue or after the blood vessels rupture and cause bleeding in the
brain (hemorrhage). These scans may include: