This is an abnormal connection between blood vessels. It happens when arteries connect directly to veins without first sending blood through tiny capillaries. An AVM can look like a tangle of blood vessels. They form anywhere in your body, but most often they form in or around the brain and along the spinal cord.
We don't understand what causes AVMs. Most people who have an AVM were born with it.
If you have one, you may not realize it. Many cause no problems. But sometimes an AVM causes noticeable symptoms. An AVM in your head can cause headaches, confusion and seizures. It can cause buzzing or whooshing noises in your ear. You may have dizziness or other vision problems. An AVM in your head or spine can cause weakness, numbness, balance issues and pain.
An AVM can keep your brain or your spinal cord from getting enough oxygenated blood. An AVM also may rupture and let blood leak out. That can cause you to have a stroke. Or, a large pool of blood may press harmfully against your brain or spinal cord. A bleeding AVM is a medical emergency.
AVMs can be removed surgically. They can be treated with catheter and radiation techniques. Your healthcare provider will create a plan that is right for you.