By Mayo Clinic Staff

Central nervous system vascular malformations are rare issues in blood vessels. They usually form in the brain or spinal cord and their coverings, called membranes.

There are several types of central nervous system vascular malformations:

• Arteriovenous malformations. Also called AVMs, these are unusual tangles of blood vessels that connect arteries and veins. AVMs can be anywhere in the body, but most happen in or near the brain or the spine. This type poses the highest risk of brain bleeds and other complications.
• Capillary telangiectasias. These are small blood vessels, called capillaries, that are wider than usual.
• Cavernous malformations. These blood vessels in the brain or spinal cord don't form correctly. They look like mulberries or popcorn.
• Dural arteriovenous fistulas. These are unusual connections between arteries and veins. They happen in the tough covering over the brain or spinal cord called dura. These connections between arteries and veins can lead to bleeding in the brain or other symptoms.
• Venous malformations. These are enlarged veins in the brain or spinal cord. They're also called developmental venous anomalies.

Symptoms depend on the type of central nervous system vascular malformation and where it's found. Some vascular malformations have no symptoms. They may be found on imaging done to look for another condition.

Symptoms for some central nervous system vascular malformations may include:

• Bleeding.
• Seizures.
• Headache.
• Brain and nervous system problems, called neurological deficits, that get worse over time. Neurological deficits may affect speech, vision, balance, memory and other abilities.

The cause of central nervous system vascular malformations is unclear. Some are present at birth, called congenital. Others may happen later. Some may be caused by a change to a gene, called genetic.

Injury to the central nervous system also may cause these malformations.

A family history of vascular malformations or genetic conditions, such as hereditary hemorrhagic telangiectasia, may increase the risk of vascular malformations. Rare congenital factors, such as blood vessels not developing as they should before birth, increase risk for the condition. Nervous system injuries also may increase risk.

Central nervous system vascular malformations can damage the brain or spinal cord. Damage may come from bleeding, called hemorrhage, into nearby tissues. Once bleeding happens, there's a greater risk of having another bleed.

Vascular malformations also may block oxygen flow to tissues and put pressure on parts of the brain or spinal cord. Being pregnant also may increase the risk of bleeding for someone who has a vascular malformation.

Other complications can include:

• Stroke.
• Brain damage from a burst blood vessel.
• Death.
• Learning and behavior problems in children.

You can't prevent vascular malformations. But if you have any known risk factors, there are a few ways to help with early detection and management.

• Monitoring helps find early signs of malformations using imaging. This is especially important if there is a family history of malformations or related genetic or congenital conditions. Your care team can discuss the best imaging tests for you and how often you need them.
• Managing other conditions such as inflammation and high blood pressure. While this does not prevent malformations, it may lessen the chances of complications such as hemorrhage.

To diagnose a central nervous system vascular malformation, a healthcare professional looks for a family history of stroke, epilepsy or related conditions. You may have a physical exam, and your healthcare professional may listen to the sound of blood flow in one of your arteries with a stethoscope. Some vascular malformations make a whooshing sound called a bruit. Fast blood flow through a malformation causes the bruit.

Imaging tests can detect a central nervous system vascular malformation. A magnetic resonance angiogram or a computerized tomography angiogram might be used to diagnose a central nervous system vascular malformation and plan treatment.

An angiogram shows blood flow through arteries or veins. A contrast material is put into the blood through an IV. The contrast lights up blood vessels on the angiogram image.

Some vascular malformations, such as cavernous malformations, are found using regular MRI or CT scans.

Treatment of a central nervous system vascular malformation depends on:

• The type of malformation.
• Where it’s found.
• Symptoms it causes.
• The risk of the malformation bleeding.

Sometimes, watching for changes in the malformation might be all that’s needed.

Medicines to treat the symptoms of venous malformations include antiseizure medicines to treat seizures and pain relievers for headaches.

Some central nervous system vascular malformations that are very likely to bleed may be removed with surgery. The procedure depends on the malformation.

• Surgery involves cutting into the brain or spinal cord to remove the malformation. Surgery is often used for an arteriovenous malformation that is small and in a place that's easy to reach.

  As with any surgery, there are risks, such as infection and blood loss. There's also a risk of damaging nearby healthy tissue.

• Stereotactic radiosurgery uses radiation beams aimed at the vascular malformation. The radiation damages the walls of the blood vessels that form the malformation. This causes the malformation to go away over time.

  Because radiosurgery doesn't involve cutting, the risks are lower than with standard surgery. However, there's a risk of radiation damage to healthy tissue.

• Endovascular embolization involves using a long, thin tube called a catheter. The tube is put into an artery in the leg or groin that feeds the malformation. It's then threaded to the brain using X-ray imaging to guide it.

  The surgeon sends coils or a gluelike substance through the tube that blocks the artery and lowers blood flow to the malformation.

  Embolization often is used with other surgical procedures. It might not completely remove the malformation, or the results might not last long.

If you have symptoms of a central nervous system vascular malformation, you might start by seeing your primary care provider. Or you might learn you have a malformation after having imaging tests for another condition. You might then be referred to a doctor who specializes in conditions of the nervous system, called a neurologist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if you need to do anything in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms. Include any that seem unrelated to the reason for your appointment and when they began.
• Key medical information. Include personal and family medical history.
• All medicines, vitamins or other supplements you take. Include doses.

For central nervous system vascular malformations, basic questions to ask your healthcare professional include:

• What's likely causing my symptoms?
• What tests do I need?
• Is my condition likely temporary or chronic?
• What's the best course of action?
• What is my risk of having complications from this condition?
• I have other health conditions. How can I best manage them together?
• Are there brochures or other printed material I can have? What websites do you recommend?

Be sure to ask all the questions you have about your condition. If possible, bring a family member or friend to your appointment to help you remember the information you're given.

What to expect from your doctor

Your health professional is likely to ask you questions such as:

• How often do your symptoms happen?
• How painful are your symptoms?
• What, if anything, seems to make your symptoms better?
• What, if anything, seems to make your symptoms worse?

If you have symptoms of a central nervous system vascular malformation, you might start by seeing your healthcare professional. Or you might learn you have a malformation after having imaging tests for another condition. You might then be referred to a doctor who specializes in conditions of the nervous system, called a neurologist.

Here's some information to help you get ready for your appointment.

When you make the appointment, ask if you need to do anything in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms. Include any that seem unrelated to the reason for your appointment and when they began.
• Key medical information. Include personal and family medical history.
• All medicines, vitamins or other supplements you take. Include doses.

For central nervous system vascular malformations, basic questions to ask your healthcare professional include:

• What's likely causing my symptoms?
• What tests do I need?
• Is my condition likely temporary or chronic?
• What's the best course of action?
• What is my risk of having complications from this condition?
• I have other health conditions. How can I best manage them together?
• Are there brochures or other printed material I can have? What websites do you recommend?

Be sure to ask all the questions you have about your condition. If possible, bring a family member or friend to your appointment to help you remember the information you're given.

Your health professional is likely to ask you questions such as:

• How often do your symptoms happen?
• How painful are your symptoms?
• What, if anything, seems to make your symptoms better?
• What, if anything, seems to make your symptoms worse?