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Arteriovenous Malformation


What is an arteriovenous malformation?

An arteriovenous malformation (AVM) is an abnormal connection between arteries and veins. The connection becomes tangled. Blood flows too quickly from the arteries and pushes on the walls of the veins. The walls weaken and become narrow (stenosis). The artery walls also become weak. They begin to bulge from blood that is not able to go into the narrow veins. A brain AVM affects the blood vessels of the brain. An AVM can also affect other organs as well. A brain AVM that has not burst usually causes no symptoms, or may cause headaches or seizures. If it bursts, blood leaks into surrounding tissue, and may cause a stroke. The blood leaking can also cause your brain to swell.

How is an AVM diagnosed?

An AVM that has not burst may be found only when your healthcare providers are doing tests for other conditions. Your healthcare provider will ask about your medical conditions and examine you. You may also need any of the following tests. You may be given contrast liquid to help arteries and veins show up better in the pictures. Tell the healthcare provider if you have ever had an allergic reaction to contrast liquid.

  • An angiogram is used to check for problems with blood flow in your brain. X-rays are taken as contrast liquid goes into blood vessels in your brain.
  • A CT or MRI scan may be used to take pictures of blood vessels and tissue in your brain. You may be given contrast liquid before the pictures are taken. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the healthcare provider if you have any metal in or on your body.

How is an AVM treated?

These treatments may be done alone or with other treatments:

  • Surgery may be needed to repair or remove your AVM. If the AVM has already bled, surgery may be needed to repair burst blood vessels, or remove blood from your brain. Your healthcare provider will use the size, location, and depth of the AVM to decide whether surgery is right for you. Surgery can also be used to treat the abnormal blood vessels to prevent them from rupturing or bleeding.
  • Endovascular embolization may be 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 into 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. Healthcare providers use the catheter to put chemicals, metal coils, or plastic beads in the AVM to stop the blood flow to it.
  • Radiation therapy , also called radiosurgery, uses radiation, such as a gamma knife, to treat the AVM. Radiosurgery is done if your AVM is deep or in a part of your brain that microsurgery cannot be done. You may have to go back several times to complete this therapy.

Call or have someone else call 911 if:

  • You have any of the following signs of a stroke:
    • Numbness or drooping on one side of your face
    • Weakness in an arm or leg
    • Confusion or difficulty speaking
    • Dizziness, a severe headache, or vision loss
  • You have a seizure.
  • You have the worst headache of your life.

When should I contact my healthcare provider?

  • You have repeated migraine headaches.
  • You have questions or concerns about your condition or care.

Care Agreement

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. 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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.