An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels that irregularly connects arteries and veins, disrupting blood flow and oxygen circulation. Arteries move oxygen-rich blood from the heart to the brain and other organs, while veins drain the oxygen-depleted blood back to the lungs and heart. When an AVM disrupts this critical process, the surrounding tissues might not get enough oxygen, and the tangled blood vessels in an AVM can weaken and rupture. AVMs can form anywhere in the body, but they are most commonly found in the brain and spinal cord.

The cause of AVMs is not clear, but they are rarely hereditary, meaning passed down in families. Most people are born with AVMs, but they can form later in life. AVMs can cause a variety of symptoms, depending on their location, including headaches, dizziness, vision problems, seizures, and changes in thinking or neurological function. AVMs have a high risk of bleeding, which can cause brain damage, stroke, or even death.

AVMs can be diagnosed through imaging tests such as CT scans or MRIs, and treatment options include surgery, radiation therapy, and embolization. If you have any of the symptoms of an AVM, such as headaches, dizziness, vision problems, seizures, and changes in thinking or neurological function, you should seek medical attention.