Home / Conditions / Brain aneurysm
A bulge in a blood vessel wall in the brain. Most never rupture and many are found by accident during a scan for something else. A ruptured one is an emergency. The two situations could hardly be more different, and this page separates them.
A ruptured brain aneurysm is life-threatening and every minute counts. Go to an emergency department immediately — do not wait, do not drive yourself, and do not call a clinic first.
A sudden severe headache is the single most important sign. Most turn out to be something else — but that is a conclusion for an emergency department to reach, not for you to reach at home.
Call 995An aneurysm is a weak point in the wall of a blood vessel that balloons outward under the pressure of blood flowing past it. In the brain they typically form where vessels branch, and are often described as looking like a berry on a stem.
Most cause no symptoms and are never discovered. Of those that are, the great majority are found incidentally — during a scan for headaches, after a head injury, or as part of investigation for something else entirely.
If one ruptures, blood escapes into the space around the brain. That is a subarachnoid haemorrhage, a form of haemorrhagic stroke, and it is a surgical emergency.
Most aneurysms are saccular — a rounded pouch bulging from one side of the vessel on a narrow neck, the berry on a stem. The neck is what makes them treatable: a clip can be placed across it, or coils packed into the sac through it.
A fusiform aneurysm is different. The vessel widens all the way round over a length of its course, so there is no neck to clip and no sac to pack. These are the aneurysms that flow-diverting stents were developed for — a mesh placed along the vessel that redirects blood past the weakened segment and lets it heal.
Most form around the Circle of Willis, the ring of arteries at the base of the brain, because branch points are where wall stress is highest.
This is the situation most people reading this page are actually in: a scan has shown an aneurysm, nothing has happened, and it is frightening out of proportion to the immediate risk.
Three things are worth knowing.
What you want from a consultation is not reassurance or alarm, but a clear account of what your specific aneurysm means and what the options are — including the option of doing nothing except watching it.
Most produce none at all. When a larger one presses on nearby structures it can cause:
A new drooping eyelid with a dilated pupil, or a new severe pain behind one eye, should be assessed the same day. These can indicate an aneurysm that has enlarged or is about to rupture.
The first two are the ones you can change, and both matter more than people expect. If you have an unruptured aneurysm and you smoke, stopping is the most effective thing available to you.
Aneurysms are found and characterised by imaging. Which test is used depends on the situation:
Two approaches are used, and the choice depends on the aneurysm's size, shape and position rather than on preference.
Performed from inside the blood vessel, with no opening of the skull. A catheter is passed from an artery at the wrist or groin up to the aneurysm, and it is sealed from within.
Devices include coils, stents, flow-diverting stents and intra-aneurysmal flow disruptors, alone or in combination. Dr Tung works with interventional neuroradiologists on these procedures.
Recovery is generally quicker than open surgery, and follow-up imaging is used to confirm the aneurysm stays sealed.
An open operation. A section of skull is temporarily removed, the vessel feeding the aneurysm is located, and a small metal clip is placed across its neck to stop blood entering it.
It remains the better option for certain aneurysms — particular shapes and locations are more reliably treated this way, and a clip placed successfully is a permanent solution.
For many small unruptured aneurysms, the right course is regular imaging to check for change, alongside control of blood pressure and stopping smoking.
This is an active decision, not a failure to treat. Where the risk of intervention exceeds the risk of the aneurysm, monitoring is the better medicine.
Almost certainly not in the immediate sense. Around one person in fifty has an aneurysm, and the great majority never rupture. What matters is getting a proper assessment of your particular one so the decision about treatment or monitoring is made on evidence rather than anxiety.
No. Treatment carries risk of its own, and for small aneurysms in low-risk locations, careful monitoring is often the better option. That judgement depends on size, shape, position, your age and your other risk factors.
Screening is sometimes recommended where two or more close relatives have had a brain aneurysm, or where there is polycystic kidney disease in the family. It is a decision to make individually rather than a routine test.
Most people with an unruptured aneurysm are not restricted from normal activity, though very heavy straining is usually discouraged. This is worth asking specifically about your own case rather than assuming either way.
Clipping is open surgery placing a clip across the aneurysm's neck from outside. Endovascular treatment seals it from within the vessel using coils or a flow-diverting device. Which is appropriate depends on the aneurysm rather than on preference.
No. You can book directly. Bring the scan images and the report — the images themselves, not only the written report, as the measurements and shape matter.
Stroke · Headaches (all types) · Concussion · Dizziness and vertigo · Neurosurgery
If an aneurysm has been found on a scan, bring the images. You will leave understanding what yours means and whether it needs treating.
