Arteriovenous malformations (AVMs) are tangles of abnormal blood vessels. They can form wherever arteries and veins exist. They can be found anywhere in the body. AVMs of the central nervous system (brain and spinal cord) are the most serious.

Arteriovenous Malformation in the Brain
AVM brain blood vessels
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The cause of AVMs is unknown.

Risk Factors

Your chances of AVMs are higher if:

  • They run in your family—your genes may play a role
  • You had a head injury
  • You had surgery or radiation therapy


In many cases, AVMs don’t cause problems. In those that have them, symptoms differ between people. They depend on the size and site of the AVM.

AVMs in the brain may cause:

  • Headaches
  • Seizures
  • Loss of movement on one side of the body
  • Weak muscles
  • Problems with certain movements
  • Loss of coordination, mainly when walking
  • Sudden, severe back pain
  • Speaking problems
  • Vision problems
  • Memory loss
  • Confusion or thinking problems

Serious complications of bleeding can lead to:


The doctor will ask about your symptoms and health history. AVMs may be found during testing for another reason. You may have:


You may need to see a specialist for care. The goals of care are to remove or damage the AVM, and prevent bleeding.

Care depends on if the AVM has ruptured or not. Sometimes, more than one method is used. Care may be in a hospital.


Medicines help ease symptoms. They also manage problems of an AVM that hasn’t ruptured. Medicines treat:

  • Pain
  • Seizures
  • Pressure inside the skull
  • High blood pressure
  • Blood clots


If the AVM ruptured, surgery may be delayed for 2-6 weeks. The type depends on the size and site of the AVM. Options include:

  • Microsurgery—An operation to remove the AVM through a hole in the skull. A special microscope will help the surgeon see the area.
  • Embolization—A tube is inserted through the skin. It is passed through arteries until it reaches the AVM. A substance is passed to the area. It will block off blood flow to the AVM. This is a more common option with AVMs found deeper in the brain.
  • Radiosurgery—A beam of radiation is focused on the AVM. It destroys the blood vessel walls leading up to the AVM. This will block off blood flow to AVM. Stereotactic radiosurgery (SRS) delivers radiation to an exact site. It decreases damage to nearby tissue.


There is no way to prevent AVMs since the cause is unknown.

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