Medical Centric

Arteriovenous Malformations

Nervous System Diseases / By

Arteriovenous Malformations

  • Arteriovenous malformations (AVMs) are abnormal, snarled tangles of blood vessels that cause multiple irregular connections between the arteries and veins.
  • These malformations most often occur in the spinal cord and in any part of the brain or on its surface but can develop elsewhere in the body.
  • AVMs can damage the brain and spinal cord by reducing the amount of oxygen reaching neurological tissues, bleeding into surrounding tissue (hemorrhage) that can cause stroke or brain damage, and by compressing or displacing parts of the brain or spinal cord.
  • This usually happens during development before birth or shortly after.

Stages of AVM

  • AVMs grow and change over time.
  • AVMs are often organized using a scale called the Schöbinger staging system.
  • Not all AVMS go through every stage.

Stage I (quiescence)

  • The AVM is “quiet.” The skin on top of the AVM may be warm and pink or red.

Stage II (expansion)

  • The AVM gets larger. A pulse can be felt or heard in the AVM.

Stage III (destruction)

  • The AVM causes pain, bleeding, or ulcers.

Stage IV (decompensation)

  • Heart failure occurs.

Causes

  • The cause of brain AVMs is not known, and many believe that they are congenital.

Symptoms

  • Symptoms of AVMs depend on where the malformation is located.
  • AVMs have a high risk of bleeding.
  • AVMs can get bigger as a person grows.
  • They often get bigger during puberty, pregnancy or after a trauma or injury.
  • A person with an AVM is at risk for pain, ulcers, bleeding and, if the AVM is large enough, heart failure.
  • An AVM can be mistaken for a capillary malformation (often called a “port wine stain”) or an infantile hemangioma
    These are physical symptoms:
  • Buzzing or rushing sound in the ears
  • Headache — although no specific type of headache has been identified
  • Backache
  • Seizures
  • Loss of sensation in part of the body
  • Muscle weakness
  • Changes in vision
  • Facial paralysis
  • Drooping eyelids
  • Problems speaking
  • Changes in sense of smell
  • Problems with motion
  • Dizziness
  • Loss of consciousness
  • Bleeding
  • Pain
  • Cold or blue fingers or toes

Diagnosis

  • AVMs are usually diagnosed through a combination of magnetic resonance imaging (MRI), angiography and CT scan.
  • These tests may need to be repeated to analyze a change in the size of the AVM, recent bleeding, or the appearance of new lesions.
  • The Spetzler-Martin Grade (SMG) scale is commonly used as a grading scale to predict the risk of surgical morbidity and mortality with brain AVMs.

Treatment

  • Treatment options depend on the type of AVM, its location, noticeable symptoms, and the general health condition of the individual.
  • Medication can often alleviate general symptoms such as headache, back pain, and seizures caused by AVMs and other vascular lesions.
  • The definitive treatment for AVMs is either surgery to either remove the AVM or to create an artificial blood clot to close the lesion or focused irradiation treatment that is designed to damage the blood vessel walls and close the lesion.
  • The decision to treat an AVM requires a careful consideration of possible benefits versus risks.