Cardiovascular and Interventional Radiological Society of Europe

Intracranial aneurysm


An intracranial aneurysm is a blood-filled bulge in the wall of a blood vessel in the brain, which occurs at a weak point in the blood vessel.

As a result, intracranial aneurysms are associated with a high risk of bleeding around the brain, known as subarachnoid haemorrhage, and in the brain itself, known as intracerebral haemorrhage, though this is less common. Subarachnoid haemorrhage and intracerebral haemorrhage are types of intracranial haemorrhage and can have catastrophic consequences.


A small intracranial aneurysm usually does not produce many, if any, symptoms until it ruptures, causing subarachnoid haemorrhage. The most frequent symptom of this is a severe headache, but you may also experience nausea and vomiting, neck stiffness, blurred vision, alteration in consciousness and seizures.

However, if you have a large intracranial aneurysm, you are more likely to be aware of it before it ruptures, as it may distort your normal anatomy. There are a number of neurological symptoms that you may experience, depending on the structure affected, including problems with vision, cognition, perception, speech, behaviour, balance, concentration, memory or fatigue.


CT scan or MRI of your brain can be used to diagnose you. In order to plan the optimal treatment for you, a doctor may need to perform a cerebral angiogram, which uses X-ray-based techniques.


There are a number of possible treatments for intracranial aneurysms. The aneurysm may be treated surgically through an opening in your skull. A clip is then placed on the vessel, which stops blood flow to the aneurysm, making it harmless.

Alternatively, you may have a minimally invasive treatment, in which blood flow to the aneurysm is stopped, but instead of this being carried out through a hole in your skull, the doctor will direct a microcatheter to the aneurysm from an artery in your groin under X-ray guidance, and will then place tiny metal coils into the aneurysm to block it.

If you undergo either of these treatment methods, you will need to stay in hospital.