Overview
An arteriovenous malformation (AVM) is an abnormal cluster of blood vessels that can occur anywhere in the brain. Blood flows through them at excessively high pressures, but bypasses the brain tissue without nourishing it.
If you have an AVM, it is likely that you have had it since birth. The abnormal blood vessels which make up an AVM have weak walls. This means that the blood vessels tend to widen over time and then rupture, causing intracranial haemorrhage.
Symptoms
The symptoms you experience depend on the location and size of the AVM. Although you may not have any symptoms at all, it is also possible to experience symptoms such as seizures, a headache that won’t go away, weakness or numbness. You may also experience a buzzing sound in your head. If the AVM begins to bleed, you may develop symptoms of a subarachnoid haemorrhage or, less commonly, of acute stroke.
Diagnosis
Your doctor can diagnose you using a CT scan or MRI of your brain. In order to plan the optimal treatment for you, a doctor may need to perform a cerebral angiogram (or DSA) under X-ray guidance with a contrast substance injected directly into your brain.
Treatment
There are three possible treatments for an AVM: endovascular embolisation, surgical removal and stereotactic radiosurgery. The treatment that is most suitable for you depends on the size and location of the AVM and whether or not it has bled. It is fairly common for patients to have to undergo more than one treatment.
If you undergo endovascular embolisation, an interventional radiologist will direct a microcatheter to the AVM through an artery in your groin, and will then plug the abnormal blood vessels with glue.
Stereotactic radiosurgery is a form of radiotherapy in which the AVM is exposed to focused beams of gamma rays, thereby severely damaging the abnormal blood vessels. This means that blood flow gradually slows to a halt and the AVM shrinks and, over several months or years, turns into a scar. You will need to stay in hospital for these procedures.