An arteriovenous malformation (AVM) is a congenital vascular lesion occurring in the brain. An AVM is composed of a tangled collection of abnormal blood vessels that send arterial blood into the venous system without the usual connecting capillary network. AVMs are likely to hemorrhage because the vessel walls are thinner and more tortuous, and because the blood flow is accelerated and pressure is elevated within the vessel walls.
Arteriovenous Malformation Symptoms
Symptoms of arteriovenous malformations depend on where the malformation is located.
Physical symptoms include:
- buzzing or rushing sound in the ears
- headache - although no specific type of headache has been identified
- loss of sensation in part of the body
- muscle weakness
- changes in vision
- facial paralysis
- drooping eyelids
- problems speaking
- changes in a sense of smell
- problems with motion
- loss of consciousness
Complications of arterio venous malformations include:
- hemorrhage (stroke)
- numbness in part of the body
- problems with speech or movement
- in children, developmental delays
- lower quality of life
- small risk for death from hemorrhage
Diagnosis of Arteriovenous Malformations
Doctors typically take a medical history and do a physical exam. Family and friends can describe the symptoms they saw, especially if the person with symptoms is unconscious. The final diagnosis, however, is usually made based on imaging tests that show areas of blood flow. These tests could include:
- Cerebral angiogram
- MRI scan and magnetic resonance angiography
- CT scan
- Vascular ultrasound
Arteriovenous Malformations Treatment
In many cases, medication can alleviate general symptoms of arterio venous malformation, like headache, back pain and seizures. However, surgical intervention is usually required and is often the neuroendovascular technique of embolization.
In embolization, a microcatheter is guided into the blood vessels that feed the AVM. Through the catheter, types of "super glue" or particles are injected into the malformation to block off some of these vessels. This procedure may make surgical removal of the AVM safer and decrease blood loss, or it may shrink the size of the AVM so that stereotactic radiosurgery or Gamma Knife is a possible form of arteriovenous malformation treatment.