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Arteriovenous Malformation

GENERAL INFORMATION:

What is an arteriovenous malformation? An arteriovenous malformation (AVM) is an uncommon, direct connection between blood vessels. Blood travels from the heart to areas of the body through arteries and returns through veins. When blood leaves the arteries, it normally passes through capillaries (very small blood vessels) before flowing into the veins. With AVM, capillaries are absent and blood flows quickly from the arteries and pushes hard on the walls of the veins. This can damage or weaken the blood vessels, which may cause them to bulge and get twisted. Over time, the AVM may get larger, burst, and spill blood. AVMs can be found in many parts of the body, but those in the brain can cause very serious problems if not treated. If an AVM in your brain spills blood, you may get a serious condition such as a bleeding (hemorrhagic) stroke.

What causes an arteriovenous malformation? People who have AVMs are usually born with this condition. You may also get it from an accident where there is severe (very bad) trauma to the head. Sometimes the exact cause of this condition is unknown. Having high blood pressure or blood vessels that burst before may put you at a higher risk of having AVM.

What are the signs and symptoms of an arteriovenous malformation?

• AVM without bleeding: If you have an AVM in the brain that has not burst, you may have no symptoms. You may have signs and symptoms such as seizures (convulsions), headaches, or changes in functioning. Changes in function can be problems with walking, talking, or other functions controlled by your brain.
  
  
• AVM with bleeding: If an AVM in your brain bursts and spills blood, you may have a hemorrhagic stroke (bleeding in the brain) or a subarachnoid hemorrhage (bleeding around the brain). The signs and symptoms of these conditions depend on which part of the brain is affected. You may have one or more of the following:
  
  
  • Blindness in one eye, or blurred or double vision.
    
    
  • Changes in your personality or in how you normally act.
    
    
  • Nausea (upset stomach) or vomiting (throwing up).
    
    
  • Numbness (loss of feeling), tingling, weakness, or paralysis (being unable to move) on one side of your body.
    
    
  • Seizures (convulsions).
    
    
  • Severe (very bad) headache, dizziness, confusion, or passing out.
    
    
  • Trouble walking, swallowing, talking, thinking, understanding, or remembering things.

How is an arteriovenous malformation diagnosed? AVMs that have not burst may be found only when your caregivers are doing tests for other conditions. If you have an AVM or symptoms of one, your caregiver will ask about your past medical conditions and their treatment. He will do a physical and neurological exam on you. You may have tests where dye will be put into your vein. This will help the blood vessels show up better. Tell your caregiver if you are allergic to shellfish, as you may also be allergic to the dye used for this test. You may have any of the following:

• Angiogram: This test is used to check for problems with blood flow in your brain. A special dye is put into your vein (IV), which will help the AVM show up better. X-rays are taken as the dye goes into blood vessels in your brain.
  
  
• CT scan: This is also called a CAT scan. A special x-ray machine uses a computer to take pictures of your brain. It may be used to look at bones, muscles, brain tissue, and blood vessels. You may be given dye before the pictures are taken. The dye is usually given in your IV. The dye may help your caregiver see the pictures better.
  
  
• MRI: This test is called magnetic resonance imaging. During the MRI, pictures are taken of your head. An MRI may be used to look at the brain, muscles, joints, bones, or blood vessels. You will need to lay still during a MRI. Never enter the MRI room with an oxygen tank, watch, or any other metal objects. This can cause serious injury. Tell your caregiver if you have any metal implants in your body.

How is an arteriovenous malformation treated? Treatment depends on your health condition, and the size, location, and severity of the AVM. You may have one or more of the following:

• Brain surgery: The AVM is repaired or removed through an incision (cut). You may also need surgery to repair any burst blood vessels or remove spilled blood in your brain. Ask your caregiver for more information about brain surgery (craniotomy).
  
  
• Embolization: This procedure may be done as the only treatment for your AVM. Sometimes this treatment is done before you have surgery or radiation therapy. Having this procedure done first helps to make the AVM smaller and easier to treat with the other methods. This procedures uses a very small tube (catheter) put in a large blood vessel in your groin, and then passed up to the AVM in your brain. The groin is the area at the top of your leg. The AVM is then treated to stop the blood flow through it. Caregivers may use dye and a special type of x-ray machine to locate the AVM. There are several types of this treatment, and one or more may be used during your procedure:
  
  
  • Chemical embolization: Liquid adhesive, ethyl alcohol, and polymer compound are chemicals used for this type of embolization. One or more of these chemicals may be used during your treatment.
    
    
  • Coil embolization: A very small metal coil is placed into the AVM, and more than one may be used.
    
    
  • Particle embolization: This procedure uses very small plastic beads injected into the AVM.
  
  
• Radiation therapy: This is also called radiosurgery. It uses special x-ray machines, such as a gamma knife, to treat the AVM. You may have to go back several times to complete this therapy. Ask your caregiver for more information about radiation therapy.
  
  
• Stroke treatment: An AVM that bursts may cause you to have a bleeding (hemorrhagic) stroke. Ask your caregiver for more information about hemorrhagic stroke.

Where can I find more information?

• National Institute of Neurological Disorders and Stroke
  P.O. Box 5801
  Bethesda, MD 20824
  Phone: 1-800-352-9424
  Web Address: http://www.ninds.nih.gov
  

• National Stroke Association
  9707 E. Easter Lane
  Englewood, CO 80112
  Phone: 1-303-649-9299
  Phone: 1-800-787-6537
  Web Address: http://www.stroke.org
  

CARE AGREEMENT:

You have the right to help plan your care. To help with this plan, you must learn about your health condition and how it may be treated. You can then discuss treatment options with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

References and sources