An arteriovenous malformation (AVM) is an abnormal tangle (like a bird’s nest) of blood vessels. The tangle is made of arteries that would normally supply brain tissue and veins that would normally drain brain tissue.
What causes an arteriovenous malformation (AVM)?
Scientists aren’t sure what causes arteriovenous malformations. They believe they develop during pregnancy, so you’re born with an AVM (they’re congenital). Some cases have been reported in people with head trauma or certain infections. Only in rare cases are AVMs thought to be hereditary (run in families).
What are the symptoms of arteriovenous malformations?
You may or may not have symptoms if you have an arteriovenous malformation. Up to 15% of people with AVMs don’t have symptoms. Often, the first sign you have an AVM is after it bleeds.
Brain AVM: If you have a brain AVM and it leads to a blood vessel bleed (rupture), it can cause a stroke and brain damage. About 50% of people with a brain AVM have a brain bleed (hemorrhage) as their initial symptom.
AVMs can irritate the surrounding tissue, causing neurologic symptoms, including:
Seizures with or without loss of consciousness.
Headache. (The nature of pain, duration, frequency and severity vary from person to person.)
Muscle weakness or complete paralysis.
Nausea and vomiting.
Numbness or tingling sensation.
Dizziness.
Problems with movement, speech, memory, thinking, balance or vision.
Mental confusion, hallucinations or dementia.
Spinal cord AVM: If you have a spinal cord AVM, symptoms include:
Back pain (can be sudden and severe) or weakness in your lower body (hips) and legs to your toes.
Muscle weakness or paralysis in your body areas of the affected nerves.
AVMs in other locations: If you have AVMs in other locations in your body (other than your brain and spine), you may or may not have symptoms depending on their size and the significance of the location. General symptoms may include:
Shortness of breath during exertion.
Coughing up blood (if the AVM is in your lungs).
Abdominal pain.
Black stools/poop (if the AVM is in your digestive tract).
Lumps on arms or legs or on your trunk.
Pain and swelling.
Muscle weakness or paralysis.
Numbing or tingling sensation.
Sores or open ulcers on your skin.
What are the treatments for arteriovenous malformations (AVMs)?
Treatment choices depend on the type, size and location of the AVM, risk of AVM rupture, your symptoms, your age and your general health. Ideally, the goal of treatment is to reduce the chance of bleeding or make it permanently go away. Surgery on your brain and spinal cord is serious, with risks including complications and death. Each person, and each person’s AVM, is unique and there aren’t any perfect decision-making tools in all cases. In general, though, treating an arteriovenous malformation as soon as possible is usually the best way to avoid serious complications.
One or more of these approaches might be tried:
Surgery to remove the AVM. Surgery involves making a small incision near the AVM, sealing the surrounding arteries and veins so they don’t bleed, then surgically removing the AVM. Blood flow is redirected to normal blood vessels. Surgery is a cure of this condition.
Embolization. In this procedure, a catheter is inserted into an artery in your groin and moved to the location of the AVM. Once there, a glue-like substance, coils or other substance is released into the AVM, which slows or stops the blood flow through the AVM. This approach is used when the AVMs are large and have a lot of blood flow through them. This way, they can be more easily removed with less risk of bleeding if surgery is performed immediately afterward. Embolization can also slow blood flow to reduce rupture if surgery isn’t immediately performed.
Gamma knife radiosurgery. This approach uses highly focused beams of radiation that slowly shrink, scar and dissolve an AVM over a few years or make the AVM easier to remove with surgery.
What happens if these standard treatment approaches can’t be tried?
AVMs can be complicated. There may be times when the AVM might be located in an area where the dangers of surgery or other treatments are of greater concern and pose a greater risk than doing nothing at all. If this is the case, your healthcare team may choose to carefully monitor your AVM with imaging tests over time. If the AVM begins showing signs of change, indicating an increased risk of bleeding, treatment may be considered at that time. Each person and each arteriovenous malformation is unique. Your healthcare team will talk to you and your family about your particular situation and the best way to approach your AVM.
What happens after brain surgery for an arteriovenous malformation (AVM)?
You’ll have a brain scan to make sure the AVM has been completely removed or destroyed. You’ll also have a short hospital stay (a few days) and undergo some short-term rehabilitation.
If you have the gamma knife treatment, you’ll have scans from time to time to see if the AVM is shrinking.
What medications are used to help treat arteriovenous malformations?
Medications can be given to relieve some of the symptoms of AVMs. These include:
Anti-seizure medications.
Pain relievers for headache and back pain.
What are the risks of arteriovenous malformations (AVMs)?
The biggest risk of having an AVM is that it might bleed. If the AVM is in your brain, a brain bleed causes a stroke, brain damage or seizures. Because these areas are enclosed, AVMs can also press on and displace parts of your brain and spinal cord.
AVMs reduce the amount of oxygen in the areas in which they exist. A reduced oxygen level damages tissue.
How are arteriovenous malformations (AVMs) diagnosed?
Your healthcare provider will ask you about your symptoms and conduct a physical exam. They’ll sometimes listen for a bruit, which is a rapid blood flow sound heard in arteries and veins when an AVM is present.
Imaging tests used to detect arteriovenous malformations include:
Catheter angiography. A tube, called a catheter is inserted into an artery in your groin and moved to the area to be investigated. Dyes and X-rays are used to view details of your blood vessels.
Ultrasound. Uses sound waves to produce pictures.
Brain imaging tests for suspected brain AVMs may include:
Cerebral magnetic resonance angiography (MRA). Uses magnetic field and radio waves to produce detailed pictures of your blood vessels in and around your brain.
Computed tomography angiography (CTA). Uses X-rays to see detailed pictures of your blood vessels.
Transcranial Doppler ultrasound. Uses sound waves to determine the speed of blood flow through your brain.
Because many AVMs don’t cause symptoms, some are only discovered during an imaging test for another condition (such as injuries, vision problems or headaches) or after they bleed and cause symptoms.
What are the complications of arteriovenous malformations (AVMs)?
Aneurysm. This is a balloon-like bulge in the walls of any of the blood vessels feeding into or around the AVM (arteries, veins the AVM itself). They develop because of a structural weakness in your blood vessel walls. Aneurysms develop in about 50% of all brain and spinal cord AVMs.
Brain damage that affects thinking, mental processing, memory or understanding speech.
Coma and death, especially from a large bleed in your brain.
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