ARTERIOVENOUS MALFORMATION

An arteriovenous malformation (AVM) is an entanglement of blood vessels that forms as a result of the failure of embryonic vessels to separate into arteries and veins. These malformations are exceptionally thin and without the normal characteristics of arteries or veins. The thinness of the vessels and the pressure of large amounts of blood flowing through them make AVM blood vessels susceptible to rupture, causing bleeding within the brain (Cavernous Malformations/AOVMs are often confused with AVMs. However, AOVMs symptoms and effects are different.)

Also, the increased supply of blood flowing through the AVM causes a decrease in the blood supply to other parts of the brain. This rerouting of the blood supply deprives critical tissue of sufficient blood supply. This deficiency causes damage to tissue within and around the AVM.

SYMPTOMS

Although some arteriovenous malformations do not cause symptoms, many become symptomatic in patients between the ages of 10 and 30 years old. Some of the symptoms include:

	Hemorrhage - Bleeding is one of the most frequent initial symptoms of an AVM and can be either within the brain or beneath the membrane (meninges) that covers it.
	Seizure - Another frequent initial symptom, may be preceded by unusual sensory events such as a disagreeable odor, bitter or metallic taste, ringing or hissing sound, a sense of familiarity with an unfamiliar environment, or a sense of unfamiliarity with familiar environment. Seizures usually include loss of consciousness and uncontrolled shaking of the body, but some seizures may not be associated with loss of consciousness.
	Migraine-like Headache - These may be sudden and severe or they may be more chronic. The combination of seizure activity and headache should prompt careful consideration of the presence of an arteriovenous malformation.
	Bruit - (pronounced brew-ee) This is a noise or murmur caused by the abnormal blood flow to the AVM, which is heard in rhythm with the heartbeat.

OTHER SYMPTOMS

	Fainting, dizziness, weakness
	Loss of sensation or tingling
	Loss of language skills (written or spoken)
	Mental confusion
	Dementia
	Loss of intellectual abilities (memory, judgment, thinking)
	Changes in personality
	Paralysis

TREATMENT

The most effective treatments for arteriovenous malformations are surgical removal and stereotactic radiosurgery. These may be augmented by embolization. Your physician will talk to you about the appropriate treatment for you and possible side effects.

TREATMENT WITH GAMMA KNIFE RADIO SURGERY

If an AVM cannot be surgically removed because of its location or if the patient is a poor candidate for surgery, the Gamma Knife offers a safe and effective way to manage an AVM. A single, highly concentrated dose of gamma radiation is delivered to a small, precise target including the nest (nidus) of abnormal vessels. Unlike surgical removal, Gamma Knife Radiosurgery does not result in the immediate destruction of the AVM, but causes it to shrink over time.

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