Are brain aneurysms usually fatal?

Sometimes. There is good amount of study performed on the natural history of brain aneurysms. Aneurysms under 5 mm tend to have a low rate of rupture an hence not very dangerous. Conversely, the larger aneurysms (specially those larger than 1 cm) are very dangerous and every time they bleed kill 50% of the patients. Hence, if your aneurysm has not ruptured, it is important to discuss the risks with a md.
Ruptured or not? Ruptured brain aneurysms can cause devastating neurological injury with up to a 50% mortality (death) rate if left untreated. Non-ruptured aneurysms generally have little or no symptoms and may be treated electively if they are large enough (>5mm), are growing, or have a very irregular shape. The precise size of non-ruptured aneurysms which require treatment is controversial.
Sometimes. If a brain aneurysm ruptures, there is a 40% of death before you make it to the hospital and a 50% chance of poor outcome or death of those who do make it to the hospital.

Related Questions

Do you know are all brain aneurysm's fatal?

No. The majority can be handled by medical therapy, and the bulk of the remaining can be treated by interventional techniques or surgery. While a rupture of a brain aneurysm can be fatal, a large number of these can handled medically or interventionally. Read more...
No. There are multiple internet sites providing information regarding brain aneurysms. Consider http://www.Webmd.Com/brain/tc/brain-aneurysm-topic-overview, http://www.Bafound.Org/brain-aneurysm-basics, or http://brainaneurysm.Com. Read more...

Nrmal mra 8 years ago. 2 of my 2nd degree paternl relatives had fatal brain aneurysms age 38 42. My doc says no repeat mra needed. What should I do?

Difficult question. I think you should be screened - see: http://www.Ncbi.Nlm.Nih.Gov/pubmed/10648430 and: http://www.Ncbi.Nlm.Nih.Gov/pubmed/14752379 the fact that your relatives are 2nd degree relatives is reassuring. The fact is: no one knows the best screening frequency for this. I wish you well. Read more...
I think worthwhile. I think given your family history, it may be reasonable to obtain a 3t tof mra (no radiation, no contrast so very safe) every five years. Particularly around the perimenopausal time is when it might be worthwhile. The average age of aneurysm rupture is 52. Please see brain aneurysm center for women for more information. www.chicagoaneurysm.com. Read more...
Discuss. It doesn't sound like your previous study showed anything. If you are that concerned, discuss that with your doctor. If a repeat study is negative, try to relax. Read more...