Arteriovenous malformation (AVM) in the brain

A cerebral arteriovenous malformation (AVM) is a disorder of the blood vessels in the brain, in which an abnormal connection exists between arteries and veins. It's present at birth (congenital). AVMs appear as a tangle of normal or dilated blood vessels. They can occur in any part of the brain. The cause isn't clear.

AVMs often cause no signs or symptoms until complications develop, such as bleeding into the brain. But some produce a whooshing sound (bruit) that can be heard on examination with a stethoscope. Other signs and symptoms may include:

• Pulsing noise in the head (pulsatile tinnitus)
• Headache
• Progressive weakness or numbness

If bleeding occurs, signs and symptoms may include:

• Sudden, severe headache
• Weakness or numbness
• Vision loss
• Difficulty speaking
• Inability to understand others
• Severe unsteadiness

A doctor may confirm a diagnosis of an AVM by:

• Computerized tomography (CT) scan of the head
• Magnetic resonance imaging (MRI) of the head
• Brain (cerebral) angiogram
• Magnetic resonance angiography (MRA)

Treatment is directed at preventing bleeding and may include:

• Surgical removal of the AVM
• Sealing the abnormal blood vessels by injecting a glue-like substance that stops blood flow (embolization)
• Destroying the abnormal blood vessels with high-intensity radiation (gamma-knife radiosurgery)

Treatment has its risks, including brain damage, depending on the size and location of the AVM. You and your doctor must weigh the risks and benefits. In some cases, your doctor may recommend observation without specific treatment.