In Australia, more than 1,600 aneurysms rupture each year. Of all those that are known to have a subarachnoid haemorrhage 39% have died within 4 weeks. This figure may even be higher as studies have shown that if people with known unruptured aneurysms are followed until they burst closer to 66% die. The cause for death or disability can be due to:The rupture itself. As the bleeding is under considerable pressure it can do local damage to brain tissue or it can reduce the flow of blood to much of the brain (as the pressure normally driving the blood through the arteries and into the vein can be negated by the high pressure after a subarachnoid haemorrhage).The aneurysm can re-bleed and again cause the above damage. The chance of re-bleeding are particularly high in the first 24 hours but if a haemorrhage has gone undetected then there is a 50% chance that the aneurysm will bleed again with 6 months. When a re-bleed occurs 50% of people die even when they are in hospital at the time of the re-bleed
The International Subarachnoid Aneurysm Trial -- or ISAT -- is the only multi-center, prospective randomized trial comparing the safety and efficacy of endovascular coil treatment with neurosurgical clipping for the treatment of ruptured brain aneurysms. The study found that, in patients equally suited for both treatment options, endovascular coil treatment produces substantially better patient outcomes than surgery in terms of survival free of disability at one year.
Unruptured Cerebral Aneurysm Symptoms: Most aneurysms are asymptomatic, particularly ones that are small. Occasionally, large aneurysms may cause the following symptoms related to pressure on the adjacent brain or nerves: Peripheral vision deficits, Thinking or processing problems , Speech complications, Perceptual problems, Sudden changes in behavior, Loss of balance and coordination, Decreased concentration, Short-term memory difficulty Fatigue.