South Dakota Senator Undergoes Surgery for AVM

Medical Author: Melissa Conrad Stoppler, MD
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR

South Dakota Senator Tim Johnson underwent surgery on Wednesday, December 13, 2006 for bleeding in the brain caused by a rare but often fatal condition known as an arteriovenous malformation (AVM) of the brain.

An arteriovenous malformation is a congenital disorder (meaning that it is present at birth) of the blood vessels in the brain, brainstem, or spinal cord characterized by a complex, tangled web of abnormal arteries and veins connected by one or more fistulas (abnormal communications).

About 300,000 Americans are estimated to have an AVM, and most people with an AVM do not develop symptoms. However, about 12% of those affected will develop significant symptoms from an AVM. Most commonly, symptoms include hemorrhaging (bleeding), seizures, headaches, and neurological problems such as paralysis or loss of speech, memory, or vision. Hemorrhage is the most serious complication of AVMs. While most hemorrhages associated with AVMs are small, massive hemorrhages that led to death have also occurred. It is estimated that between 2 and 4% of all AVMs will hemorrhage each year.

When symptoms from an AVM occur, they most often develop in early adulthood (before the age of 40). However, older persons may experience a seizure or an episode of bleeding related to an AVM. AVMs occur equally in persons of both sexes and all races.