Arteriovenous Malformations

Causes of Arteriovenous Malformation

Arteriovenous malformations occur when arteries in the brain connect to nearby veins without having normal capillaries between them. Arteriovenous malformations vary in size and location within the brain. An arteriovenous malformation rupture occurs because of pressure and damage to brain tissue, as well as a lack of blood flow to the brain. Symptoms can occur when arteriovenous malformations press on the brain tissue, even if they haven’t bled. Although congenital, symptoms can occur at any age. People ages 15-20 often experience hemorrhaging, but hemorrhages can appear later in life. Cerebral arteriovenous malformations occur in less than 1% of people.

Symptoms of Arteriovenous Malformations

An arteriovenous malformation that has not bled can produce several symptoms, including:

  • Decreased sensation in the body
  • Localized headaches, or migraine headaches
  • Seizures
  • Vision changes, including blurred vision, decreased vision and double vision
  • Decreased consciousness
  • Dizziness
  • Dysfunctional movement
  • Eyelid drooping
  • Facial paralysis
  • Fainting
  • Impaired smell
  • Speech impairment

An arteriovenous malformation will often not produce symptoms until it has ruptured. Once an arteriovenous malformation ruptures, bleeding in the brain will occur. Hemorrhaging is the first symptom in over half of patients with arteriovenous malformation.

Treatment for Arteriovenous Malformations

An arteriovenous malformation that has ruptured is a medical emergency.

The goal of treatment is to prevent further complications by controlling bleeding and seizures, hopefully by removing the arteriovenous malformation altogether. Treatments for arteriovenous malformation include:

  • Open brain surgery – removes the malformation through an opening made in the skull.
  • Embolization – injecting a glue-like substance into the abnormal vessels to stop blood flow in the arteriovenous malformation, and reduce the risk of bleeding. This is often the first form of treatment for certain arteriovenous malformations.
  • Radiosurgery – stereotactic radiosurgery deliver radiation directly to the area of the arteriovenous malformation, causing it to scar and shrink.

Anti-convulsant medications are usually prescribed if seizures occur.

Diagnosis and Prognosis

A complete physical examination and neurologic examination is needed, but may be completely normal.
Dr. Moza, a Ventura County neurosurgeon, may recommend the following tests to diagnose an arteriovenous malformation::

  • Cerebral angiogram
  • Cranial MRI
  • Electroencephalogram (EEG)
  • Magnetic resonance angiography (MRA0)

Death can occur if hemorrhaging is the first symptom of arteriovenous malformations. Roughly 10% of cases result in death if hemorrhaging is the first symptom. Persistent neurological problems and permanent seizures can be effects of arteriovenous malformations.

Complications of Surgery

Complications vary from patient to patient. Complications may include:

  • Focal weakness
  • Intracerebral hemorrhage
  • Linguistic (speaking) disabilities
  • Numbness of the body
  • Permanent neurological changes, such as paralysis or sensory issues
  • Persistent headaches
  • Seizures
  • Subarachnoid hemorrhages
  • Vision changes
  • Hydrocephalus – water on the brain
  • Brain swelling