High ALT in a dog.

Autumn went to the vet on Sept 29, 2013 with a problem jumping and walking on stairs. She was prescribed Rimadyl. On Oct 5, she was given a blood test and had an ALT of 320. She was taken off the Rimadyl, as it was suspected it was the cause, and put on Denamarin (which she has been on since that date and continues to take). On Oct 17 her ALT was 290(which seemed at that point to confirm Rimadyl was the problem). She was put on Clavamox for some severe skin alergy/fungus issues she was having. She was also put on Tramadol for her issues with jumping. She had Lyme and DHLPP shots on Oct 19. On Nov 7, her skin problems returned and she was put on Atopia and another antibiotic (do not recall the name). On Nov 21, her ALT was 600. She was taken off Atopia and the other antibiotic and put back on Clavamox. Autumn had x-rays on Sept 29 and again on Nov 21 that showed nothing of interest. On Dec 3, her ALT was 900. For this entire time, she had been on Sentinel and Frontline and was taking a probiotic once a day, due to what we thought had been stress related diarrhea she had on multiple occasions in the past. Autumn completely overcame the jumping and stairs issues by late November and has no problems with that anymore (never really discovered what the problem was). On Dec 7, Autumn had an ultrasound with findings "unremarkable, except for a liver size that is a bit on the small side". On that same day, a bile acid test was abnormal (pre-meal was okay at 5.9 umol/L (normal 0-7), but post meal was significantly elevated at 91.9 with normal being < 15. Urinalysis was unremarkable. Between Dec 3 and Feb 13, Sentinel and Frontline medications and also probiotics were not given to Autumn. On January 1, a "mass with features consistent with a hyperplastic nodule" was removed during a liver biopsy. Other sections of her liver exhibited "prominent vacuolar change, but no evidence of significant inflammation, fibrosis, or necrosis. It is "nonspecific and suggestive of hepatocellular compromise/injury, not necessarily glycogen". Autumn's ALT was 850 the day of surgery. In mid-Jan, Autumn was started on Vitamin E and Ursodiol. On Jan 21, her ALT was 923 (somewhat expected after the trauma to the liver during surgery), but on Feb 13, it was down to 229 (and we were hopeful that the removal of the nodule during the biopsy had solved her problem). On Feb 13, Autumn had started having skin problems again and was put on another antibiotic. She also resumed Frontline and was switched to Heartguard. Autumn has been on Hills Science Diet LD for much of this time. In mid-April, Autumn's ALT was back to 650. On May 13, it was 590. For this entire time, Autumn has exhibited no indication that she is not feeling well. The vet did find a blood test that had been performed 2 years earlier and Autumn's ALT was actually 200 in that report. She is currently still taking Denamarin and vitamin E and is on Hills LD, but we are also letting her have chicken and rice. She is also continuing the Heartguard and Frontline. We have no idea what is wrong with Autumn and are at a loss as to what to do next or what medications might be best for her.