Thank you for your reply. I have discussed GVD with the specialist. They do not think that this is it (although I agree with you, really sounds like it). They said it would be really rare in a young dog, although it could happen. I forget exactly why they've ruled that out... also the fact that he's had 3 episodes so far, and has been totally asymptomatic in between, except for this last time.... might still be this: i am hoping it is, because otherwise, whatever is going on could be much worst... I will ask the specialist again when they call. Thanks!