I doubt the Giroux head-thing is anything major.
I've had two concussions in my life and both kept me in bed for a couple days while I cleared out the dizziness/fuzziness. Just to get up and walk to the bathroom made me nausious (sp?). If the worst concussions are worse than what I've had, then there's no way Giroux would've even tried to get on a plane to return to North America. He would have stayed in bed for much longer and returned when his head felt well enough to move around.
That's sort of just speculation based on my own experience with concussions.