Arteriovenous malformation (AVM)
What is an arteriovenous malformation?
- Normally, arteries carry blood with oxygen from the heart to the brain and body.
- Veins carry blood with less oxygen back to the heart.
- Capillaries connect arteries to veins.
When an arteriovenous malformation (AVM) occurs, the capillaries are missing. The arteries connect directly to the veins. This causes the blood to flow very fast through these large vessels.
What does an AVM look like?
At birth, the skin on top of the AVM may be pink or red. Over time the skin will look dark red or purple. It may be a small area such as a lip, or it may take up an entire arm or leg. The skin over the malformation usually feels warmer than other skin. A pulse from the heartbeat may be felt.
AVMs are most common in the head but may appear anywhere on the body or internal organs.
What causes it?
The cause of an AVM is not known. They may have a genetic link. They are present at birth (congenital), but less than half are diagnosed at birth. It may take years to be diagnosed.
How is it diagnosed?
The diagnosis must be confirmed by an MRI or a CT scan. Scans must be done to see how big the malformation is.
What are the complications?
- Crusting and bleeding on the skin.
- Severe bleeding (hemorrhage).
- Headaches and other symptoms if the AVM is in the head.
- Heart failure may develop due to the large amount of blood that flows through the AVM.
How is it treated?
- Embolization. Tiny particles or coils are injected into the malformation. This slows the flow of blood in the AVM. Embolization is usually done before surgery to help decrease the blood loss during surgery.
- Surgery. Surgery will remove as much of the AVM as possible. Several surgeries may be needed to remove the entire AVM.
- Sclerotherapy. A chemical is injected into a blood vessel. This will cause the inside of the vessel to swell so blood cannot flow through it. The vessel will then collapse and form scar tissue.
Are there other problems that are linked to AVMs?
Some AVMs may be linked to a group of problems called a syndrome. Your doctor will ask you questions about the family health history. The syndromes linked to AVMs are Bannayan-Riley-Ruvalcaba syndrome, Cowden syndrome and Parkes-Weber syndrome.
Are there other websites or references that may be helpful?
Alert: Call your child's doctor, nurse, or clinic if you have any concerns or if your child has:
- Sudden swelling.
- An infection that will not heal.
- Bleeding that will not stop.
- Special health care needs not covered by this information.