What is an arteriovenous malformation?
An arteriovenous malformation (AVM) is a tangle of arteries and veins in the brain that disrupt the normal flow of blood. This is a condition that is usually present at birth. In rare cases, AVMs are associated with conditions that run in families.
Though they are most common in the brain, AVMs can also occur in other parts of the body.
In brain AVMs, the blood travels directly from the arteries to the veins instead of moving through the capillaries first. This can cause several problems in the brain, including stroke, abnormal fluid balance, hydrocephalus, or, in rare cases, heart failure.
Watch: Learn more about AVMs
Arteriovenous Malformations | Symptoms & Causes
What are the symptoms of brain arteriovenous malformations?
Brain arteriovenous malformations (AVMs) sometimes cause no symptoms and are only found during imaging for other reasons. More commonly, though, AVMs can cause bleeding in the brain, seizures, and other neurological problems.
Symptoms can include:
- Seizures
- Persistent headaches
- Weakness or paralysis on one side of the body
- Problems with speaking
- Loss of coordination
- numbness, tingling, or pain
What causes brain arteriovenous malformations?
The cause of AVMs is not known. In most cases, children are born with them. In rare cases, AVMs are associated with conditions that run in families.
Arteriovenous Malformations | Diagnosis & Treatments
How are brain arteriovenous malformations diagnosed?
The first step in diagnosing brain arteriovenous malformations (AVMs) is often neurological testing to assess the child’s brain function. Genetic testing may also be recommended if your clinician suspects an inherited disorder.
To help choose the best treatment, your clinician may also order one or more of the following imaging tests:
- Magnetic resonance imaging (MRI)
- CT angiography (CTA)
- Magnetic resonance angiography (MRA)
- Cerebral angiography can often provide additional information about an AVM with highly detailed images of the arteries and veins.
How are brain arteriovenous malformations treated?
The choice of treatment for brain arteriovenous malformations (AVMs) is very individual and depends on the AVM’s complexity, how easy it is to reach surgically, and whether removing it would risk interfering with vital brain functions.
In most cases, AVMs are removed by surgery if this option is safe and possible.
Endovascular embolization
If the AVM is complex, especially if it is supplied by deep, hard-to-reach blood vessels, the clinician may recommend endovascular embolization as a separate step before surgery.
Endovascular embolization is a minimally invasive technique that closes off as much blood flow as possible to the AVM. It can make surgery easier and safer. Embolization is performed under general anesthesia by a neurointerventionalist with the help of specialized anesthesiologists, nurses, and technologists, using x-ray guidance.
During the procedure, the neurointerventionalist inserts a catheter (a thin, flexible tube) into an artery in the groin through a tiny incision and guides it to the AVM. The catheter injects a specially designed medical glue, filling as much of the area around the AVM as possible. In most cases, the child will have embolization first, stay overnight in the ICU, and then have surgery the following morning.
Stereotactic radiosurgery
Stereotactic radiosurgery is often used when traditional surgery is too risky because the brain AVM is hard to reach or is in an area of the brain that controls vital functions such as language. This procedure involves no incisions. Instead, the radiosurgeon aims a tightly focused beam of high-energy radiation directly at the AVM. This radiation causes the abnormal blood vessels to wither and close down after treatment.
Other types of treatment
In addition to surgery, some children may also need treatment for any neurological symptoms the AVM may have caused. Treatments can include physical therapy or occupational therapy, or speech and language therapy.
How we care for brain arteriovenous malformations
The experts at Boston Children’s Hospital Cerebrovascular Surgery and Interventions Center treat brain AVMs and other cerebrovascular conditions.
Because we have the capability to provide the entire spectrum of cerebrovascular disease treatment options — surgery, radiation, and embolization — we're able to provide the best care plan for each child, using noninvasive procedures and limiting radiation exposure whenever possible.
