Daniel Walsh, Consultant Neurosurgeon


Brain Aneurysm


Aneurysms are blister-like dilatations which may develop on any blood vessel in the body. When they occur on the arteries supplying blood to the brain they are termed cerebral aneurysms or "berry" aneurysms, a reference to an early description of them resembling berries on a stalk.

Posterior communicating artery aneurysm compressing the oculomotor nerveStudies suggest that unruptured aneurysms are present in about 3.2% of the population. Some aneurysms bleed causing a disease called Aneurysmal Subarachnoid Haemorrhage (aSAH).

Not every aneurysm will bleed. ASAH affects about 9 in every 100,000 people each year. This therefore accounts for about 5% of stroke in the United Kingdom annually. Younger people are more frequently affected than the more common ischaemic stroke.

Rates of aSAH in Finland and Japan are higher although the numbers of unruptured aneurysms in the population is about the same suggesting there are other factors in those populations which put them at particular risk.

It is known that smoking, cocaine use and uncontrolled high blood pressure seem to increase the risk that any given aneurysm will bleed work continues to understand other factors that may promote rupture. Enviromental factors (for example cigarette smoke) may have a particularly profound effect on genetically susceptible individuals. To learn more about unruptured aneurysms click here or on the link in the menu bar at the top of this section.

Aneurysms are more common in assosciation with certain medical conditions. We know that they occur more frequently in patients affected by Autosomal Dominant Polycystic Kidney Disease (APCKD) and certain other heritable connective dissue disorders.

Infections of the heart valves (Endocarditis) can cause small pockets of infection to spread through the blood stream and into the walls of the arteries in the brain. These pockets can weaken the wall of the artery causing aneurysms to form.

To learn more about subarachnoid haemorrhage and how aneurysms are treated explore the menu bar above. If you have further questions you are welcome to contact us.