Hmmmm....ya know what comes to mind for me...possible gastric ulcers, mostly bc the symptoms are rather random in nature - can be full or empty tummy and bile/no-bile - and that's rather stomach-ulcer like.
Running bloods is always good, of course. But I almost think if it were me, I might first try a trial of
Sucralfate prior to anything else -- almost just to have that diagnostic info *first* - ya know what I mean...?
And have you already tried Pepcid? I mean, I realize it's probably not GERD, but still - have you tried it BID?
Also, see this article for
GI-duodenal ulcers.
But really importantly maybe -
see this one to see how to
culture for Heliobacter in dogs.