Just to throw yet another opinion into the mix (sorry
):
I agree about the Metacam. NSAIDs (including this one) are not recommended for dogs with probable MVD or LS. I have no idea why the vet thought it was okay, but there are better options for pain management in thi case. These drugs can mess up even a healthy dog's liver. Ellie had a post BAT of 47 and then 15. She was spayed and had a liver biopsy shortly after. NSAIDs weren't really even in her vet's thinking process for this.
Bile acids in Yorkies that are over 100 (post) are very often LS, but can still be MVD (or both) or something entirely different. Bile acids below 100 are very often MVD (but in rare cases...LS). It can also be sometihng else.
The ALT being that high would be of concern. Good that it's coming down, but I just think it was too high to not keep rechecking. We were slightly concerned when Ellie's was 118, sooooo a jump like that can't be taken lightly in a young dog. If the ALT does not go back down to normal range, then I personally would err on the side of caution and go further. I'm not necessarily saying that a biopsy needs to be done nor a scintography. I just think having a specialist deal with the high ALT may be good (if it stays where it is or goes back up). It means liver cell death probably occurred and there are some things you can do to help protect the liver from further damage (i.e. (SAMe, possibly milk thistle).