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The University of Chicago Medicine - Comer Children's Hospital

Vascular Anomalies: Arteriovenous Malformation

Arteriovenous malformations (AVM) result when there is an abnormal, or tangled, connection between an artery and a vein. AVMs are mainly seen in the brain and spinal cord, but also can be found in other parts of the body, including the skin.

Currently, there are no known causes for arteriovenous malformations. AVMs are more common in males. It is believed the malformations form during embryonic or fetal development. Nothing a pregnant mother does is known to cause or prevent AVM formation.

Signs and Symptoms

In the skin:

  • Appear as a blush color in infancy and childhood
  • Turn darker red or purple color as the child ages and a firm mass develops beneath the skin
  • A pulsing of the blood that can be felt when you touch the lesion

In the brain and spinal cord: 
Arteriovenous malformations may not cause any symptoms unless a leak or rupture occurs. However, some symptoms associated with AVMs may be experienced, such as

  • Headaches
  • Seizures
  • A whooshing sound (called a bruit) heard noticeably or during examination of skull with a stethoscope

If bleeding into the brain occurs, signs and symptoms are similar to those of a stroke and may include:

  • Weakness, numbness or paralysis in part of the body
  • Sudden, severe headache
  • Unsteadiness or dizziness
  • Loss of vision and/or control of eye movement
  • Difficulty speaking
  • Inability to understand others speaking

Symptoms of AVMs may appear at any age, but these vascular malfomations tend to remain stable and asymptomatic until around the age of 50. In women, pregnancy may start or worsen symptoms of an AVM due to the increased blood flow and blood volume during pregnancy.


One or more of the following imaging tests may be used to diagnose an arteriovenous malformation:

  • Ultrasonography
  • Magnetic Resonance Imaging (MRI)
  • Magnetic Resonance Angiography (MRA)


Treatment approaches for arteriovenous malformations differ depending on the area of the body that is involved, and can include:

  • Medication, to alleviate general symptoms. This can be helpful for those who are unable to have surgery.
  • Embolization, the injection of a material into the center of the lesion to block the blood supply of the lesion.
  • Surgical removal, to increase the chance of successful surgical removal of an AVM. A pre-operative embolization may be used to reduce blood loss.
  • Radiosurgery, a less invasive treatment that uses proton-beam irradiation

About Our Program

The Vascular Anomalies Program at the University of Chicago Medicine Comer Children's Hospital offers an integrated and comprehensive approach to the diagnosis, care and management of hemangiomas and vascular malformations. Our multidisciplinary team of pediatrics experts works together to educate families and to evaluate and treat children with all types of these vascular lesions. » Read more about our program and our team.

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