Arteriovenous malformation (AVM)

What is an arteriovenous malformation (AVM)?

A tangle of blood vessels – with an abnormal direct connection between arteries and veins.

How common are they?

They are very rare and occur in less than 1% of the population. 

Where do they occur?

AVMs can occur anywhere in the body; however brain AVMs are of special concern because they can be damaging if they bleed.

Most people with neurological AVMs do not experience any major symptoms. The malformations tend to be discovered incidentally. 

How are they diagnosed?

Arteriovenous malformations have a pulse that can be felt, or heard with a stethoscope. AVMs are usually diagnosed with medical imaging studies after symptoms such as headache, numbness, seizures, weakness, or often the abrupt onset of a stroke. 

CT or MRI scans can also usually confirm an AVM. 


The greatest potential danger posed by AVMs is haemorrhage and treatment is directed toward preventing brain injury. The treatment will depend on the AVM’s size and location – your neurosurgeon should be able to advise.

To help general symptoms such as headache, back pain, and seizures caused by AVMs. 

A technique to block blood vessels which involves injecting liquid glue or coils into the AVM. 

Radiation/Stereotactic Surgery
Focusing narrow, high-dosage x-ray beams on the AVM. 

Traditionally used to remove an AVM, often referred to as a craniotomy. 

This site does not provide medical advice and is not a substitute for medical or professional care, and if you see a birthmark growing or changing significantly, see a specialist.