Central nervous system vascular malformations


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

There are several types of central nervous system vascular malformations, including:

  • Arteriovenous malformations (AVMs). These are unusual tangles of blood vessels that connect arteries and veins. AVM can be anywhere in the body. Most often they occur 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 are blood vessels in the brain or spinal cord that are formed unusually. They look like mulberries or popcorn.
  • Dural arteriovenous fistulas. These are unusual links between arteries and the tough covering over the brain or spinal cord, called dura, and a draining vein.
  • Venous malformations. These are unusually enlarged veins in the brain or spinal cord. They also are 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're found on imaging for something else.

Symptoms for some central nervous system vascular malformations can include:

  • Bleeding.
  • Seizures.
  • Headache.
  • Brain and nervous system problems, called neurological deficits, that get worse over time. Neurological deficits can 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 come later.

Some genetic conditions can increase the risk of having vascular malformation. Injury to the central nervous system might be another cause.


Central nervous system vascular malformations can damage the brain or spinal cord. Damage can come from bleeding, called hemorrhage, into nearby tissues. Vascular malformations also can block oxygen flow to tissues and put pressure on parts of the brain or spinal cord.

Complications can include:

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

Once bleeding occurs, there's a greater risk of having another bleed. For someone who has a vascular malformation, being pregnant might increase the risk of bleeding.


To diagnose a central nervous system vascular malformation, a health care provider looks for a family history of stroke, epilepsy or related conditions. Some vascular malformations make a whooshing sound, called a bruit. Fast blood flow through a malformation causes the bruit. A provider might hear the sound through a stethoscope.

Imaging tests

Imaging tests such as an angiogram can detect a central nervous system vascular malformation. An angiogram shows blood flow through arteries or veins. Blood vessels appear on the image after a contrast dye is put into the blood. The dye lights up on the scan.

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

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 and the risk of a bleed. Sometimes watching for changes in the malformation and for the risk of bleeding might be all that's needed.


Medicines that might be used for treating the symptoms of a venous malformation include anti-seizure medicines to treat seizures and pain relievers for headaches.

Surgery or other procedures

Some central nervous system vascular malformations that pose a high risk of bleeding can be removed. The procedure depends on the malformation.

  • Surgery. This involves cutting into the brain or spinal cord to remove the malformation. Surgery is most 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. This uses radiation beams that are aimed exactly at the vascular malformation. The radiation damages the walls of the blood vessels of the malformation and causes it to go away over time.

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

  • Endovascular embolization. This technique involves the use of 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.

    Through the tube, the surgeon sends in coils or a glue-like substance that blocks the artery and lowers blood flow to the malformation.

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

Preparing for an appointment

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 there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:

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

Take a family member or friend along, if possible, to help you remember the information you're given.

For central nervous system vascular malformations, basic questions to ask 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 these 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.

What to expect from your doctor

Your provider is likely to ask you questions, such as:

  • Have your symptoms been continuous or occasional?
  • How bad are your symptoms?
  • What, if anything, seems to make your symptoms better?
  • What, if anything, seems to make your symptoms worse?

Content From Mayo Clinic Updated: 05/26/2023
© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of Use