An arteriovenous malformation (AVM) is the result of one or more abnormal connections between an artery (a blood vessel carrying blood from the heart out to the body) and a vein (a vessel returning blood to the heart).
It's a shortcut that lets blood flow from an artery to a vein without passing through tiny vessels called capillaries. That's important because oxygen and other nutrients can only pass from the blood into the body's organ through the capillaries.
Any blood that takes a shortcut through an AVM returns oxygen-rich blood to the heart instead of delivering it to the body. That means some of the heart's work is wasted, so the heart has to work harder than usual. Large AVMs or multiple AVMs can waste so much of the heart's work that it cannot keep up.
A child with an arteriovenous (ar-teer-ee-oh-VEEN-is) malformation may have these signs:
Many AVMs, especially those in the head, are not recognized until adulthood. AVMs in the head may cause:
Bleeding from an AVM can be hard to stop. Frequent bleeding may lead to anemia (a low number of red blood cells). Even small amounts of bleeding inside the skull can be very dangerous. AVMs may grow larger and cause trouble by pressing on other parts of the body.
Arteriovenous malformations are a type of vascular malformation (also called vascular anomalies) that happen when blood vessels do not develop normally.
Doctors don't know what causes AVMs. Kids who have them are born with them, and an AVM might get larger as the child grows.
AVMs can happen with some genetic syndromes, including:
Doctors often find an AVM during an exam because they can feel a pulse in its vessels. Then, they use other tools to learn more about it and plan treatment, such as:
How doctors treat an arteriovenous malformation depends on its location and size, and how it affects the child. AVMs in the arms, legs, and body are easier to treat than those in the head.
Doctors may treat an AVM to:
When a child's heart works harder than usual because of an AVM, quick treatment helps prevent long-term changes to the heart's muscle or possible heart failure.
AVMs that are not in the skull are treated with:
AVMs in the head are called intracranial AVMs. Doctors may treat these with embolization, surgery alone, or surgery with radiation (radiosurgery).
Interventional radiologists, doctors who specialize in minimally invasive image-guided procedures, usually do the embolization and sclerotherapy treatments.
How doctors treat an AVM depends on its size, where it is, and what symptoms it causes. A small AVM that's not in the head may never need treatment, but could change as a child grows. Some arteriovenous malformations get bigger, so it's important to track their size and effects on a child's health and activities.
Kids may feel shy or embarrassed about how an arteriovenous malformation looks. Be sure to support your child emotionally. It can help to find a local support group where other families can talk about what works for them. Ask your child's care team about it. You also can look online at:
Talking to a therapist can help kids and teens if they're feeling sad or upset about an arteriovenous malformation or its treatment.
Reviewed by: Stacy A. White Jr, MD
Date Reviewed: Feb 17, 2021
