Brain arteriovenous malformation (AVM) is an uncommon condition that is due to abnormal connection between arteries and veins in the brain substance. Almost 60% patients diagnosed with this condition are below 40 years of age.
There are different types, grades and location of AVM in the brain. The symptoms that patients present with depend on these above factors. Occasionally they may be detected incidentally.
Brain Arteriovenous Malformation (AVM): Causes, Symptoms, and Treatment Options
Brain AVM is a condition that affects the blood vessels in the brain. Unlike normal blood vessels, AVMs lack the necessary capillaries to connect arteries and veins. This leads to abnormal tangles and irregular connections of blood vessels. Disrupting the natural blood flow puts extreme pressure on the surrounding brain tissue and increases the risk of bleeding or rupture. Due to the potential severity of these complications, early detection and proper diagnosis, and treatment are critical for brain AVM patients.
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Common Questions About Brain AVM (Arteriovenous Malformation)
What is a brain AVM?
A brain arteriovenous malformation (AVM) is an abnormal connection between arteries and veins in the brain.
Normally, blood flows from arteries through smaller blood vessels called capillaries before reaching veins. In an AVM, arteries connect directly to veins without this normal network.
This abnormal blood flow can place increased pressure on the affected blood vessels, which may increase the risk of:
- Brain bleeding (haemorrhage)
- Seizures
- Neurological symptoms
- Other complications depending on the location and size of the AVM
What causes a brain AVM?
The exact cause of brain AVMs is not fully understood.
Most brain AVMs are believed to develop during early development before birth, although they may only be discovered later in life.
Factors associated with AVMs include:
- Abnormal development of brain blood vessels
- Rare inherited vascular conditions
- Certain genetic conditions such as hereditary haemorrhagic telangiectasia (HHT)
Unlike some vascular diseases, brain AVMs are not usually caused by lifestyle factors such as diet, exercise or high blood pressure.
What are the symptoms of a brain AVM?
Some people with a brain AVM may have no symptoms and discover it incidentally during brain imaging performed for another reason.
When symptoms occur, they may include:
- Headaches
- Seizures
- Weakness or numbness affecting one side of the body
- Difficulty speaking
- Vision problems
- Balance or coordination difficulties
- Changes in memory or concentration
Symptoms depend on the size, location and effect of the AVM on surrounding brain tissue.
Can a brain AVM cause a stroke?
Yes. A brain AVM can increase the risk of haemorrhagic stroke, which occurs when an abnormal blood vessel ruptures and causes bleeding in or around the brain.
A ruptured AVM may cause:
- Sudden severe headache
- Loss of consciousness
- Seizures
- Weakness
- Speech difficulties
- Other sudden neurological symptoms
A brain AVM requires specialist assessment to understand the individual risk of bleeding and whether treatment should be considered.
How is a brain AVM diagnosed?
Diagnosis usually involves detailed brain and blood vessel imaging.
Investigations may include:
MRI or CT brain imaging
These scans help identify structural abnormalities in the brain.
CT angiography (CTA) or MR angiography (MRA)
These imaging techniques provide information about the brain blood vessels.
Cerebral angiogram
A cerebral angiogram provides detailed images of the arteries and veins involved in the AVM.
This information helps specialists understand:
- The AVM’s size
- Location
- Blood flow pattern
- Associated risks
- Suitable treatment options
Brain Arteriovenous Malformation Causes and Symptoms
Brain AVM causes are unknown. Most mutations that advance to abnormal formations of blood vessels are believed to develop during fetal development or soon after birth. This means genetic factors may play a role in AVM development but it’s unclear if there’s a certain genetic factor or if the cases are only coincidental. Common brain AVM symptoms include severe headaches, seizures, neurological deficits, such as weakness or numbness, and, in some cases, bleeding in the brain.
Brain Arteriovenous Malformation Risk Factors
While the reasons blood vessel mutations occur remain unclear, you may be more susceptible if you have a family history of AVM. Men are also more likely to develop brain AVM than women, including individuals with inheritable disorders such as hereditary hemorrhagic telangiectasia (HTT).
The Different Types of AVM
AVMs are classified into types I to IV:
- Type I AVM poses a lower risk of rupture as it's a small, compact malformation with a single, direct artery and vein connection.
- Type II AVM is a more extensive vascular malformation, often larger in size, with multiple arterial and venous connections that present a moderate risk of rupture.
- Type III AVM is associated with a higher risk of rupture because it forms a complex malformation of tangled abnormal blood vessels, which are challenging to treat.
- Type IV AVM does not have blood vessels. A direct artery-to-vein connection without a capillary bed increases the risk of rupture.
Does Brain AVM Lead to Stroke?
Yes. Abnormal blood flow within an AVM weakens blood vessel walls over time and makes them more susceptible to rupture. A bleeding brain AVM requires emergency medical intervention, as it can result in a life-threatening stroke.
Brain Arteriovenous Malformation Diagnosis
An accurate brain AVM diagnosis helps determine a suitable treatment option. A magnetic resonance imaging test (MRI), computed tomography (CT) scan, and a cerebral angiography can enable the visualization of abnormal blood vessels or assess the size/location of the AVM.
Brain Arteriovenous Treatment Options
The treatment of brain AVM depends on the size, location, and symptoms associated with the blood vessel malformations. If the AVM is small or asymptomatic, your doctor may recommend continued monitoring without any medical or surgical intervention. Other treatment options may include:
- A minimally invasive procedure called endovascular embolization. It involves using a catheter to deliver embolic agents into the blood vessels of the AVM, reducing blood flow and promoting clot formation.
- Stereotactic radiosurgery, a non-invasive treatment method that delivers highly focused radiation to the AVM and causes blood vessels to close off gradually.
- If non-invasive treatments are ineffective, an AVM resection may be necessary to surgically disconnect abnormal blood vessels from the surrounding healthy brain tissue.
To understand how brain arteriovenous malformations develop, what symptoms they may cause, and how they are assessed in clinical practice, explore our Brain AVM Decision-Making Guide, which provides a structured overview of diagnosis, risk evaluation, and treatment decision-making.
When to Consider a Brain AVM Specialist Assessment in Singapore
A brain AVM is a complex vascular condition that requires careful evaluation of the abnormal blood vessels, associated risks and available treatment options.
Consider arranging a specialist assessment if you:
- Have been diagnosed with a brain AVM through MRI, CT or angiography.
- Have experienced seizures with an abnormal brain imaging finding.
- Have symptoms such as unexplained headaches, weakness, numbness or neurological changes.
- Have experienced bleeding related to an AVM.
- Have been advised to consider embolisation, surgery or radiosurgery.
- Want a second opinion regarding your AVM diagnosis or treatment plan.
- Need guidance on monitoring an unruptured brain AVM.
At the Supreme Vascular and Interventional Clinic, brain AVM assessment focuses on understanding the detailed anatomy of the abnormal blood vessels through advanced brain and vascular imaging. Your specialist will review the AVM characteristics and discuss whether observation, minimally invasive endovascular treatment or other approaches may be appropriate.
Seek emergency medical attention immediately if you experience sudden severe headache, loss of consciousness, seizures, sudden weakness, difficulty speaking or other sudden neurological symptoms, as these may indicate brain bleeding or stroke.
Is AVM the Same as Brain Aneurysm?
AVMs and aneurysms involve blood vessels in the brain. There is a chance that an AVM can bleed. As a result, some individuals may assume AVMs and aneurysms are the same. The conditions may have similarities, but they are different.
A brain AVM (Arteriovenous Malformation) is an abnormal tangle of blood vessels in the brain, while a brain aneurysm is a weak or bulging spot in an artery wall that can rupture and cause bleeding. Understand the differences in causes, screening, diagnosis, treatment in "Difference Between Brain AVM and Brain Aneurysm" article in our brain aneurysm resources section.
What is a brain aneurysm? The Ultimate Guide to Brain Aneurysm post can help you learn about the causes, symptoms, and treatments for this potentially life-threatening condition. We provide care and treatments at our specialized brain aneurysm clinic at Supreme Vascular and Interventional Clinic in Singapore.
Brain Aneurysm Resources
Discover brain aneurysm resources that go beyond the basics designed for patients. Understand the meaning of a brain aneurysm condition, the causes, symptoms, signs, and more. Connect with your brain health.
Put Brain Aneurysm on Your Health Radar
Did you experience the worst headache of your life? Thoughts could be racing through your mind. A brain aneurysm is a weak spot in a blood vessel in the brain that can change over time. The key concern is when an aneurysm ruptures, which can disrupt blood flow, affect brain tissue, and lead to serious brain damage. Controllable conditions like high blood pressure can increase this risk and treatment options can depend on the condition. Surgical clipping is one option that prevents blood from entering the weakened area. In many cases, minimally invasive treatments can also be used to restore normal blood flow and reduce risk. We have created structured guides to help you explore each stage in more detail:
A simple (computed tomography) CT scan could be just what the doctor ordered and the first step in early detection and prevention of a brain aneurysm. Come in for an easy consultation with our brain aneurysm specialist in Singapore to be on your health radar.
Neurointerventional Treatments
The Supreme Vascular and Interventional Clinic is your "go-to" facility for various neurological conditions and pain management. To arrange an appointment with Dr. Manish Taneja, our neurointervention specialist, contact us. You can also call us at (+65) 6904 8084 for a consultation.