A brain arteriovenous malformation is a tangle of abnormal vessels in which arteries connect straight to veins without the usual fine capillaries in between. Blood flows through under high pressure, and the thin-walled vessels can rupture.
AVMs are uncommon and most are present from early life. Treatment aims to remove the bleeding risk completely, because a partly treated AVM is not protected. For some unruptured AVMs, careful observation is as safe as intervention.
Symptoms
- Sudden severe headache with vomiting or collapse, from bleeding
- Seizures
- Weakness, numbness or speech difficulty that develops gradually or suddenly
- Visual disturbance
- A rhythmic whooshing noise in the head
- No symptoms at all, found on a scan done for another reason
Causes and risk factors
Most brain AVMs form during development before birth and are not inherited. A small number occur with hereditary haemorrhagic telangiectasia, in which case there may be nosebleeds and AVMs in the lungs or liver among relatives. Nothing a person does causes an AVM. The yearly risk of bleeding from an unruptured AVM is in the low single figures per cent, and is higher after a previous bleed, with deep location, deep venous drainage or an associated aneurysm.
How it is diagnosed
- CT and CT angiography: The first test in an emergency, showing blood and often the abnormal vessels.
- MRI: Shows the exact position relative to areas for movement, speech and vision.
- Catheter cerebral angiography: The definitive map of feeding arteries, the nidus and draining veins, needed before any treatment.
- Grading: The Spetzler-Martin grade combines size, location and drainage to estimate surgical risk.
Treatment options
- Observation with blood pressure and seizure control: Reasonable for some unruptured, high-grade AVMs where treatment risk exceeds natural risk.
- Microsurgical removal: Gives an immediate cure for accessible low-grade AVMs.
- Stereotactic radiosurgery: A focused radiation dose closes small AVMs over two to three years. The bleeding risk remains until closure is confirmed.
- Endovascular embolisation: Glue-like material injected through a catheter, mostly to make surgery safer, and occasionally curative for small lesions.
- Combined treatment: Large or complex AVMs often need staged combinations planned by one team.
When it is urgent
A sudden, worst-ever headache, collapse, a seizure, or new weakness or speech loss means call an ambulance. A ruptured AVM is treated at the nearest neurosurgical unit. Transfer abroad is only considered later, once you are stable.
Travelling to Türkiye for treatment
For an unruptured AVM or one that has bled and stabilised, there is time to choose a team, and travel is reasonable. A visit can include angiography and a joint opinion from a vascular neurosurgeon, an interventional neuroradiologist and a radiosurgery team, followed by treatment if appropriate. Radiosurgery needs only a few days, but follow-up MRI for two to three years and a final angiogram must be arranged. Ask each team how many AVMs they treat yearly.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Should every AVM be treated?
No. A large trial of unruptured AVMs found that intervention carried more short-term risk than medical management, so selection matters.
Can I exercise or fly?
Normal activity and flying are generally allowed. Discuss heavy straining and contact sports with your specialist.
Is pregnancy safe?
It needs individual advice. Many specialists prefer to treat a known AVM before a planned pregnancy.
How will I know it has gone?
Only an angiogram showing no remaining early venous filling confirms cure.