AVM – Arteriovenous Malformation: Why is Andee sick?
Andee Poulos was born with an arteriovenous malformation, or AVM. No one knows why ~300,000 Americans have this abnormality.
What is AVM? An AVM is an abnormal opening (fistula) between a cluster of arteries and veins. This fistula can occur in several areas of the body, but is most commonly found in the brain or spinal column. Andee’s AVM was at the base of her brain, and instead of her artery sending blood directly to the brain, some of that blood was being diverted, or shunted, to veins. The arteries that lead up to a fistula are under higher than normal pressure. This weakens the arterial wall and can cause a bulge (aneurysm). When the aneurysm ruptures, as happened to Andee, the effects are severe and can include paralysis, seizures, memory or vision loss, and other symptoms associated with strokes.
A large AVM bulge can interfere with the free movement of cerebrospinal fluid between the ventricles of the brain and the spinal column. When the fluid in the ventricles increases, this puts pressure on the brain itself. An AVM can form anywhere in the brain or spinal column.
A large AVM bulge can interfere with the free movement of cerebrospinal fluid between the ventricles of the brain and the spinal column. When the fluid in the ventricles increases, this puts pressure on the brain itself. An AVM can form anywhere in the brain or spinal column.
Symptoms: AVM is a “silent” disorder that usually presents before the age of 40; 80% of people with AVM never have symptoms and go undiagnosed. Symptoms can include severe headaches, back pain, and seizures. These warning signs prompt a medical workup, and diagnostic imaging will reveal the AVM. Without symptoms, the AVM may remain “silent” unless it occurs in a very sensitive area of the brain.
Treatment:
- Medication: This can control the symptoms of headache, back pain or seizures, but does not treat the cause of those symptoms.
- Surgery: This typically consists of tying off the feeder arteries, destroying the draining veins, and removing the nidus
- Endovascular occlusion: This nonsurgical (or presurgical) approach uses catheters to deliver medication that blocks blood vessel flow by triggering clot formation or hardening
- Radiosurgery: Beams using radiation to clog or harden the AVM take time to work and may damage healthy tissue; this is primarily used with very small, hard to reach areas deep within the brain, or AVMs that have multiple feeder arteries.
Measuring and predicting severity: Several universities and the National Institute of Health are using MRI (magnetic resonance imaging) to measure oxygen levels in the brain tissue that may predict response to surgery. Other nonsurgical forms of measuring brain activity, such as catheters that contain light measuring equipment, are also under development.