Possible side-effects of a brain aneurysm?

Rupture and stroke: By brain aneurysm i assume you mean an aneurysm of the middle cerebral artery. These can rupture causing bleeding in the brain, increased pressure against the brain, and eventual loss of brain function. It should be treated before the rupture occurs by a trained neurosurgeon.

Bleeding most common: Other side- effects, along with bleeding risk, include possible milder headaches, and/or less commonly symptoms of mass effect from some larger and giant aneurysms. Mass effect symptoms can include double vision or even weakness on one side if the body in extreme cases. Lastly, and even less commonly, some partially clotted aneurysms can cause strokes.