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The largest concern related to a brain arteriovenous malformation (AVM) is that they will cause uncontrolled bleeding. Fewer than four percent of AVM's cause hemorrhage but those that do can have severe and fatal effects. Death as a result of an AVM happens in about 1 percent of people. AVM's may not cause any signs or symptoms until the AVM ruptures, resulting in bleeding in the brain (hemorrhage)  In about 50% of all brain AVM's hemorrhage is the first sign.

Some people may experience signs and symptoms other than bleeding related to the AVM.  

In people without a hemorrhage, signs and symptoms may include 

  • Seizures

  • Headache or pain in one area of the head

  • muscle weakness or numbness in one part of the body

Some may experience more serious neurological signs and symptoms, depending on the location of the AVM, including 

  • Severe headache

  • Weakness, numbness or paralysis

  • Vision loss

  • Difficulty speaking 

  • Confusion or inability to understand others

  • Severe unsteadiness

Although AVM's are present at birth some are not found at that time but later in life depending on the size and location of the AVM.  As your body grows your AVM can grow and change as well. They often get larger after trauma/injury, as a child goes through puberty or during pregnancy. Symptoms may begin at any age but usually emerge between ages 10 and 40.  AVM's can damage brain tissue over time. The effects slowly build up and often cause symptoms in early adulthood.

Some pregnant women may have worsened symptoms due to change in blood volume and blood pressure causing a burden on the blood vessels. 

Anyone can be born with a brain AVM. Family history of AVM's have been reported but is it still unclear if there is a certain genetic factor or if the cases were coincidental. It is possible to inherit other medical conditions that predispose you to having vascular malformation such as AVM's.

Treatment depends on if the AVM has ever bled before, the size, location and the symptoms that it is causing. 


The Schobinger classification is a clinical assessment of vascular shunting that is predictive of treatment success.  Not all AVM's go through each stage. 


In Stage 1 the skin on top of the AVM may be warm and pink/red. Lesions being asymptomatic.


Stage 2 and 3 are intermediate with Stage 2 being the expansion stage. The AVM gets larger and a pulse can be heard in the AVM.


Stage 3 is the destruction stage, demonstrating ulceration, bleeding, pain and necrosis.


In Stage 4  heart failure can occur as a result of the decompensation stage. 

Another Grading System is the Spetzler-Martin Grading System. This is done by evaluating AVM size, pattern of venous drainage, and eloquent brain location,tmhe part of the brain that control speech, motor functions, and senses. 

A Grade 1 AVM would be considered as small, superficial and located in non- eloquent brain and is low risk for surgery. Grade 4 or 5  AVM are large, deep. and adjacent to eloquent brain. Grade 6 AVM is considered inoperable. This scale doesn't necessarily correlate with risk of treatment by embolization or radiosurgery.  


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