What is a brain arteriovenous malformation (AVM)?
A brain arteriovenous malformation (AVM) is a tangle of abnormal blood vessels connecting arteries and veins in the brain.
The arteries are responsible for taking oxygen-rich blood from the heart to the brain. Veins carry the oxygen-depleted blood back to the lungs and heart. A brain AVM disrupts this vital process.
How common is a brain arteriovenous malformation (AVM)?
Brain arteriovenous malformation (AVM) is very rare and occur in less than 1% of the general population. Please discuss with your doctor for further information.
What are the symptoms of a brain arteriovenous malformation (AVM)?
A brain arteriovenous malformation may not cause any signs or symptoms until the AVM ruptures, resulting in bleeding in the brain (hemorrhage). In about half of all brain AVMs, hemorrhage is the first sign.
But some people with brain AVM may experience signs and symptoms other than bleeding related to the AVM.
In people without hemorrhage, signs and symptoms of a brain AVM may include:
- Headache or pain in one area of the head
- Muscle weakness or numbness in one part of the body
Some people may experience more-serious neurological signs and symptoms, depending on the location of the AVM, including:
- Severe headache
- Weakness, numbness or paralysis
- Vision loss
- Difficulty speaking
- Confusion or inability to understand others
- Severe unsteadiness
Symptoms may begin at any age but usually emerge between ages 10 and 40. Brain AVMs can damage brain tissue over time. The effects slowly build up and often cause symptoms in early adulthood.
Once you reach middle age, however, brain AVMs tend to remain stable and are less likely to cause symptoms.
Some pregnant women may have worsened symptoms due to changes in blood volume and blood pressure.
One severe type of brain AVM, called a vein of Galen defect, causes signs and symptoms that emerge soon or immediately after birth. The major blood vessel involved in this type of brain AVM can cause fluid to build up in the brain and the head to swell. Signs and symptoms include swollen veins that are visible on the scalp, seizures, failure to thrive and congestive heart failure.
There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.
When should I see my doctor?
If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.
What causes a brain arteriovenous malformation (AVM)?
The cause of brain AVM is unknown, but researchers believe most brain AVMs emerge during fetal development.
Normally, your heart sends oxygen-rich blood to your brain through arteries. The arteries slow blood flow by passing it through a series of progressively smaller networks of blood vessels, ending with the smallest blood vessels (capillaries). The capillaries slowly deliver oxygen through their thin, porous walls to the surrounding brain tissue.
The oxygen-depleted blood then passes into small blood vessels and then into larger veins that drain the blood from your brain, returning it to your heart and lungs to get more oxygen.
The arteries and veins in an AVM lack this supporting network of smaller blood vessels and capillaries. Instead, the abnormal connection causes blood to flow quickly and directly from your arteries to your veins, bypassing the surrounding tissues.
What increases my risk for a brain arteriovenous malformation (AVM)?
There are many risk factors for a brain arteriovenous malformation (AVM), such as:
- Being male. AVMs are more common in males.
- Having a family history. Cases of AVMs in families have been reported, but it’s unclear if there’s a certain genetic factor or if the cases are only coincidental. It’s also possible to inherit other medical conditions that predispose you to having vascular malformations such as AVMs.
Diagnosis & treatment
The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.
How is a brain arteriovenous malformation (AVM) diagnosed?
There are three main tests that are used to diagnose AVMs. These are :
- Cerebral Angiography (Angiogram): A thin tube is inserted into an artery in the groin. This thin tube is threaded up to the blood vessels from the groin toward the brain. Dye is injected into the blood vessels of the brain and pictures are taken. An AVM will show up as a tangle of blood vessels. Doctors are able to see the exact location and size of the AVM. This is the most accurate test.
- Magnetic resonance imaging (MRI) : is a method of producing highly detailed images of the body without the need for x-rays. MR angiography (MRA) utilizes “pulse sequences ” specifically designed to show the arteries and veins of the brain as well as the AVM. MRI examination shows in detail the AVM and it relationship to the brain.
- Computerized Tomography (CT scan): uses X-rays to image different parts of the body. CT scanning is an excellent method of detecting bleeding into the brain or the fluid spaces around the brain. The study of the brain may be done either without or with dye. On the CT scan it may be possible to see an arteriovenous malformation of the brain, in particular after X-ray dye is given.
How is a brain arteriovenous malformation (AVM) treated?
Your doctor will recommend the best treatment for you and this will be determined by the size of your AVM and also the location. It is not uncommon to recommend a combination of treatments.
Another option is to do nothing at all and just monitor the AVM. Your doctors may recommend observation if they feel that treatment can not be offered safely or when an AVM is discovered at a late age.
Under general anaesthesia a small catheter (plastic tube) is advanced from the groin, into the brain vessels and then into the AVM. A liquid, non-reactive glue is injected into the vessels which form the AVM to block the AVM off. There is a small risk to this procedure and the chances of completely curing the AVM using this technique depend on the size of the AVM. It is frequently combined with the other treatments such as radiation or surgery.
This treatment is also known as Radiosurgery or Stereotactic Radiotherapy. A narrow x-ray beam is focused on the AVM such that a high dose is concentrated on the AVM with a much lower dose delivered to the rest of the brain. This radiation causes the AVM to shrivel up and close off over a period of 2-3 years in up to 80% of patients. The risk of complications is low. Until the AVM is completely closed off, the risk of bleeding still persists.
This is the oldest method for treating AVMs. The AVM is surgically removed in an operating room under general anesthesia. Since AVMs do not grow back, the cure is immediate and permanent if the AVM is removed completely. The risks of surgery are considered to be high for AVMs that are located in deep parts of the brain with very important functions.
Lifestyle changes & home remedies
What are some lifestyle changes or home remedies that can help me manage a brain arteriovenous malformation (AVM)?
The following lifestyles and home remedies might help you cope with brain arteriovenous malformation (AVM):
- Learn enough about brain AVM to make informed decisions about your care. Ask your doctor about the size and location of your brain AVM and how that affects your treatment options. As you learn more about brain AVMs, you may become more confident in making treatment decisions.
- Accept your emotions. Complications of brain AVM, such as hemorrhage and stroke, can cause emotional problems as well as physical ones. Recognize that emotions may be hard to control, and some emotional and mood changes may be caused by the injury itself as well as coming to terms with the diagnosis.
- Keep friends and family close. Keeping your close relationships strong will help you during your recovery. Friends and family can provide the practical support you’ll need, like accompanying you to doctors’ appointments, and serve as emotional support.
- Find someone to talk with. Find a good listener who is willing to listen to you talk about your hopes and fears. This may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or support group also may be helpful.
If you have any questions, please consult with your doctor to better understand the best solution for you.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: August 24, 2017 | Last Modified: November 29, 2019
Brain AVM (arteriovenous malformation). http://www.mayoclinic.org/diseases-conditions/brain-avm/home/ovc-20129992. Accessed August 25, 2017.
Brain Arteriovenous Malformations (AVM). http://brainavm.uhnres.utoronto.ca/malformations/brain_avm_index.htm. Accessed August 25, 2017.