Symptoms and causes



But some people with brain AVM may experience signs and symptoms other than bleeding related to the AVM.


  • Seizures
  • Headache or pain in one area of the head
  • Muscle weakness or numbness in one part of the body


  • Severe headache
  • Weakness, numbness or paralysis
  • Vision loss
  • Difficulty speaking
  • Confusion or inability to understand others
  • Severe unsteadiness



Some pregnant women may have worsened symptoms due to changes in blood volume and blood pressure.

One severe type of brain AVM, called a vein of Galen defect, causes signs and symptoms that emerge soon or immediately after birth. The major blood vessel involved in this type of brain AVM can cause fluid to build up in the brain and the head to swell. Signs and symptoms include swollen veins that are visible on the scalp, seizures, failure to thrive and congestive heart failure.

When to see a doctor



The cause of brain AVM is unknown, but researchers believe most brain AVMs emerge during fetal development.


The oxygen-depleted blood then passes into small blood vessels and then into larger veins that drain the blood from your brain, returning it to your heart and lungs to get more oxygen.


Risk factors


  • Being male. AVMs are more common in males.


Complications of a brain AVM include:

  • Bleeding in the brain (hemorrhage). An AVM puts extreme pressure on the walls of the affected arteries and veins, causing them to become thin or weak. This may result in the AVM rupturing and bleeding into the brain (a hemorrhage).

    This risk of a brain AVM bleeding ranges around 2 percent each year. The risk of hemorrhage may be higher for certain types of AVMs, or if you have experienced previous AVM ruptures.

    Some hemorrhages associated with AVMs go undetected because they cause no major brain damage or symptoms, but potentially life-threatening bleeding episodes may occur.

    Brain AVMs account for about 2 percent of all hemorrhagic strokes each year and are often the cause of hemorrhage in children and young adults who experience brain hemorrhage.

  • Reduced oxygen to brain tissue. With an AVM, blood bypasses the network of capillaries and flows directly from arteries to veins. Blood rushes quickly through the altered path because it isn't slowed down by channels of smaller blood vessels.




June 29, 2016