A brain arteriovenous malformation is a tangle of weakened blood vessels connecting arteries and veins. Arteriovenous malformations only occur in about 1 in every 700 people. Dr. Bernard Bendok, a neurosurgeon at Mayo Clinic, says, "While they're not real common, they can be dangerous."

A brain arteriovenous malformation often is described as a bowl of spaghetti. Arteriovenous malformation can cause severe headaches, seizures and, in some cases, a rupture.

Dr. Bendok says arteriovenous malformations can sit quietly for many years without symptoms and in a fairly unpredictable way cause a brain hemorrhage.

There are several treatments available to patients, including microsurgery; embolization, where glue is injected to close the abnormal vessels; and radiosurgery. As treatments advance, the outlook for people with arteriovenous malformations is positive.

Dr. Bendok says arteriovenous malformations can be scary, but, with modern treatments, there has never been a better time in the history for the treatment of patients with arteriovenous malformations.