Arteries carry blood containing oxygen from the heart to the brain, and veins carry blood with less oxygen away from the brain and back to the heart. When an arteriovenous malformation (AVM) occurs, a tangle of blood vessels in the brain or on its surface bypasses normal brain tissue and directly diverts blood from the arteries to the veins.

Symptoms may vary depending on where the AVM is located and may cause

  • Intracranial haemorrhage.

  • Focal or generalised seizures.

  • Localised pain in the head due to increased blood flow around an AVM.

  • Difficulty with movement, speech and vision.

Most AVMs are detected with either a computed tomography (CT) brain scan or a magnetic resonance imaging (MRI) brain scan.

If the patient is asymptomatic or if the AVM is in an area of the brain that can’t be easily treated, medical management may be indicated and no surgical intervention may be required. If an AVM has bled and/or is in an area that can be easily operated upon, then surgical removal may be recommended.  It may be possible to treat part or all of the AVM by placing a catheter inside the blood vessels that supply the AVM and blocking off the abnormal blood vessels with various materials and this is called endovascular neurosurgery. Vascular neurosurgeons specialize in surgically removing brain AVMs.