Arteriovenous Malformations

Source: MedlinePlus Health Topics, U.S. National Library of Medicine

Last synced 8/9/2026Status: primary verified

What are arteriovenous malformations (AVMs)? Arteriovenous malformations (AVMs) are defects in your vascular system . Your vascular system is your body's network of blood vessels. It includes your: Arteries, which carry oxygen-rich blood from your heart to your tissues and organs. Veins, which carry the blood and waste products back to your heart. Capillaries, which are tiny blood vessels that connect your small arteries to your small veins. An AVM is an abnormal tangle of arteries and veins. They are connected to each other, with no capillaries between them. Without the capillaries, the blood flow from the arteries goes directly into the veins at a faster rate than normal. Because of this, the nearby tissue does not get all the oxygen it would normally get. This lack of oxygen can lead to tissue damage and the death of nerve cells and other cells. The fast rate of blood flow can also increase the blood pressure inside the arteries and veins. This can weaken the arteries and veins. A weakened artery or blood vessel could burst or leak blood. What causes arteriovenous malformations (AVMs)? AVMs are rare. The cause of AVMs is unknown. Most of the time, people are born with them. But sometimes they can appear shortly after birth or later in life. What are the symptoms of arteriovenous malformations (AVMs)? The symptoms of AVM will depend on where the AVM is located. They can happen anywhere in the body, but they are more common in the brain or spinal cord. Most people with brain or spinal cord AVMs have few, if any, major symptoms. But if a weakened blood vessel bursts, it can spill blood into the brain (called a hemorrhage). Severe hemorrhages can cause a stroke and brain damage. If an AVM is causing symptoms, they can include: Seizures Headache Pain in the area where the AVM is located Vision problems Muscle weakness Problems with movement and speech Confusion Dizziness Loss of consciousness How are arteriovenous malformations (AVMs) diagnosed? To find out if you hav

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This information is for general education and is not medical advice. Always talk to a licensed U.S. clinician about your situation, medications, or treatment decisions.