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Arteriovenous Malformation


What is an arteriovenous malformation? An arteriovenous malformation (AVM) is an abnormal connection between arteries and veins. Blood flows too quickly from the arteries and pushes on the walls of the veins. This can damage or weaken the veins and cause them to bulge and get twisted. If they burst, blood will leak into surrounding tissue, and may cause a stroke. People who have AVMs are usually born with this condition. The exact cause is not known.

What are the signs and symptoms of an arteriovenous malformation? An AVM that has not burst usually causes no symptoms. An AVM that bursts and leaks blood may cause a stroke or a subarachnoid hemorrhage (bleeding around the brain). The signs and symptoms depend on which part of the brain is affected:

  • Blindness in one eye, or blurred or double vision

  • Changes in your personality or in how you act

  • Nausea or vomiting

  • Numbness, tingling, weakness, or paralysis on one side of your body

  • Seizures

  • Severe headache, dizziness, confusion, or passing out

  • Trouble walking, swallowing, talking, thinking, understanding, or remembering things

How is an arteriovenous malformation diagnosed? An AVM that has not burst may be found only when your caregivers are doing tests for other conditions. Your caregiver will ask about your medical conditions and examine you. He may take detailed images of your brain and the structures inside your head. Dye may be put into your vein to help the images show up better. Tell your caregiver if you are allergic to shellfish or iodine. You may also be allergic to the dye.

  • Angiogram: This test is used to check for problems with blood flow in your brain. X-rays are taken as the dye goes into blood vessels in your brain.

  • CT scan: This is also called a CAT scan. An 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.

  • MRI: This scan uses powerful magnets and a computer to take pictures. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell caregivers if you have any metal implants.

How is an arteriovenous malformation treated?

  • Surgery: Your caregiver will grade your AVM based on its size, location, and depth. This will help him decide whether surgery is right for you. The AVM will be repaired or removed. You may also need surgery to repair any burst blood vessels or remove blood from your brain.

  • Embolization: This procedure may be done as the only treatment for your AVM. Sometimes it is done before surgery or radiation to make the AVM smaller and easier to treat. A catheter (tube) is put in a large blood vessel in your groin, and guided up to the AVM in your brain. Dye and an x-ray machine may be used to locate the AVM. Caregivers use the catheter to put chemicals, metal coils, or plastic beads in the AVM to stop the blood flow to it.

  • Radiation therapy: This is also called radiosurgery. It uses x-ray machines, such as a gamma knife, to treat the AVM. You may have to go back several times to complete this therapy.

What are the risks of arteriovenous malformation?

  • Treatment may not remove the AVM. You may get another AVM, even after treatment. You may get an infection after surgery or bleed more than expected during surgery. You may develop brain damage. AVM treatment during pregnancy puts both the mother and the unborn baby at risk. The increased blood pressure that occurs with pushing the baby out during delivery can affect the AVM.

  • Left untreated, your AVM may get bigger or more tangled, and have a greater chance of bursting. You are at risk of a stroke if the AVM bursts. Blood may build up and block other blood vessels. The areas not getting enough blood can be damaged or even die. Blood that stays in the brain too long may cause brain swelling. The swelling can cause long-term problems, such as trouble talking, thinking, or moving your arms and legs.

When should I contact my caregiver? Contact your caregiver if:

  • Your blood pressure is higher than you were told it should be.

  • You are having trouble with occupational or physical therapy exercises given after surgery.

  • You have questions about the timing of pregnancy.

  • You have questions or concerns about your condition or care.

When should I seek immediate care? Seek care immediately or call 911 if:

  • You have chest pain that spreads to your arms, jaw, or back.

  • You have trouble breathing.

  • You have signs of a stroke:

    The following signs are an emergency. Call 911 immediately if you have any of the following:

    • Weakness or numbness in your arm, leg, or face (may be on only one side of your body)

    • Confusion and problems speaking or understanding speech

    • A very bad headache that may feel like the worst headache of your life

    • Not being able to see out of one or both of your eyes

    • Feeling too dizzy to stand


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

© 2013 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of the Blausen Databases or Truven Health Analytics.

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.

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