Did they do a full blood panel on your cat? If he had "gotten into something" most likely you would see some values way off. I would definitely get at least a full blood panel/urinalysis and see if they can find something.
Oh my nearly 8 years ago I posted this plea for help and lost track of all your wonderful efforts to help! Ned is alive and well after surgery for a liver shunt (rarer in cats) that he was born with. It meant that each time he ate (especially protein heavy food like his first canned food extravaganza) he was overloaded with toxic by products of protein digestion that never passed through his liver for processing. In fact, I think I posted his issue on another smaller site somewhere that someone mentioned had a vet who would chime in and she literally saved ned with her diagnosis! By that I mean she said his symptoms sounded very much like a liver shunt and she encouraged me to find someone familiar with it. This was enough to push for a final attempt at diagnosis at the north Carolina state university instead of my MI vets referral to a neurological specialist. At nc they diagnosed and corrected the shunt beautifully! Ned gained 7 pounds within that year! Sure, these days we deal with a little extra Pudge but his liver is healthily working and the vet expects ned to have a long life. The liver shunt would have been fatal with a terrible painful end within a year if we had let it run its course. The surgery was around 5k, in the interest of disclosure for anyone seeking answers.
I don't know if I ever found the vet and other site to thank her, as I also forgot to come here and give thanks and updates. That time was a stressful time of illness and recovery and thinking back I'm so grateful we made it through. Thank you all(if you ever see this again) from the bottom of my heart!
