Still, in the rare case that an aneurysm pops, or ruptures, it can be lethal. As many as 40% of people with a ruptured brain aneurysm will die, and 40% of survivors will be left with brain damage.

CT angiography of basilar tip aneurysm Shazia Mirza and Sankalp Gokhale (2016-07-25). Credit: Wikimedia commons. Neuroimaging in Acute Stroke. Attribution 4.0 International (CC BY 4.0) ...

Note the large aneurysm at the tip of the basilar artery. PICA = posterior inferior cerebellar artery, AICA = anterior inferior cerebellar artery, SCA = superior cerebellar artery, PCA = posterior ...

The bleeding risk aside, a large basilar aneurysm can press on the brain stem, causing serious nerve-related symptoms. Indeed, excruciating pain and arms and legs suddenly too weak for gardening ...