Arteriovenous malformations (AVMs) are very rare. They occur when a group of blood vessels forms incorrectly, usually before birth or shortly after. Arteries and veins are unusually tangled and may not supply blood properly to brain tissue. Most people with AVMs have no symptoms. Sometimes AVMs are discovered when doctors treat other unrelated health problems and perform imaging tests.
Symptoms that do occur can include a rushing sound in the ears, headache, backache, seizures, muscle weakness, vision changes, problems speaking and dizziness. Of concern is AVM rupture and related bleeding (hemorrhage), a rare but potentially fatal condition. Patients with a suspected AVM require expert diagnosis and treatment, which may include endovascular embolization, surgical resection and Gamma Knife radiosurgery.