Arteriovenous Malformations

Definition

Arteriovenous malformations (AVM) of the brain and spinal cord are tangles of abnormal blood vessels. They can form wherever arteries and veins exist. The ones that form in the brain or spinal cord have the most serious symptoms.

Arteries in arteriovenous malformations don’t flow properly. They dump blood directly into veins through a channel called a fistula, an abnormal tube-like opening. The blood flows through this fistula too quickly.

Arteriovenous Malformation in the Brain

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If you suspect you have this condition, contact your doctor immediately.

Causes

The exact cause of arteriovenous malformations is unknown.

Risk Factors

Risk factors that increase your chance of getting arteriovenous malformations include:

• Family history—some types of arteriovenous malformations are from genetic defects that can be passed on from one generation to the next.
• History of bleeding—some types of arteriovenous malformations are linked to an increased risk of bleeding. People with unexplained recurrent bleeding may be at higher risk of having arteriovenous malformations.
• Smoking

Symptoms

There are a number of symptoms that you may have if you have an arteriovenous malformation. Symptoms vary from person to person. They also depend on the location of the arteriovenous malformation in your body.

If you have any of these symptoms, do not assume it is due to arteriovenous malformations. These symptoms may be caused by other, less serious health conditions.

• Seizure—occurs in 20%-25% of all cases
• Headache
  • Headaches are a common symptom that affect about 15% of cases. Sometimes headaches linked to one side of the head may be a sign that an arteriovenous malformation is there.
• Muscle weakness
• Paralysis (loss of movement) on one side of the body
• Dizziness
• Unable to perform movements but not due to paralysis (also known as apraxia)
• Loss of coordination, especially when walking (also known as ataxia)
• Sudden, severe back pain
• Difficulty speaking or understanding language
• Loss of senses (hearing, taste, or touch)
• Visual problems
• Memory loss
• Difficulty thinking or mental confusion
• Hallucinations (sensing things that do not exist)
• Dementia

Children under the age of two may have different symptoms such as:

• Hydrocephalus (excessive build-up of fluid within the brain—gives the appearance of a large head)
• Seizures

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Your doctor will need more information to make an evaluation. Your doctor may order some tests to get a full understanding of your condition.

Your doctor may need pictures of your body structures. This can be done with:

• Angiography or arteriography
• X-rays using a catheter and contrast agent
• Computed axial tomography (CT scan or CAT scan)
• Magnetic resonance imaging (MRI)
• Magnetic resonance angiogram (MRA)

Your doctor will most likely refer you to a specialist for an exam and treatment. There are a number of specialists who focus on arteriovenous malformation such as neurologists, neurosurgeons, and interventional neuroradiologists.

Treatment

The goal of treatment is to prevent hemorrhaging. Hemorrhaging can lead to strokes. Your doctor will need to determine if your arteriovenous malformation has bled, if it is not too large, and if it is in an area that can be easily reached and treated.

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

There are three different types of surgery available. Choosing a surgery type will depend on the size and location of the arteriovenous malformation. The types of surgery include:

Sometimes, arteriovenous malformations are best left alone based on their size and location. It is best to speak with your physician about your decision.

Prevention

There is no way to prevent an arteriovenous malformation. To help reduce your chances of hemorrhaging, take the following steps:

• Learn about ways to avoid high blood pressure, such as:
  • Avoid heavy lifting.
  • Stop smoking.
  • Maintain a healthy weight.
  • Limit alcohol.
  • Eat a healthy diet that is low in sodium.

• Avoid blood thinners (drugs such as warfarin).
• Continue to see your doctor and a neurologist to regularly check the condition of your arteriovenous malformation.