Current Mood: slightly less worried but still displeased
So after looking at some perfectly normal to not-a-smoking-gun test results, the vet took an X-ray of Tazz's lower back, and found a probable cause: Tazz has a slipped disc, poor guy. We're going to go with the (recommended) conservative treatment approach, which is to increase his prednisolone (or prednisone, I can never remember which cat is taking which variant) dose to a full tab daily, up from his current half tab. It is hoped that over the course of 3-4 months, Tazz will at least get no worse, and will hopefully regain some of the strength in his hindquarters. He's comfortable and can come on home tonight.
(The not recommended, aggressive course of treatment, for those who are curious, is an MRI and surgery.)
His current state, however, makes our lives kind of complicated. He's effectively bedridden, which means that he needs the same kind of care as a human bedridden patient: we need to figure out how to 'turn' him so that he doesn't get kitty bed sores. Which means one of us needs to come home at midday to care for him, or we need to stagger our work schedules, or Huz may work from home a little more frequently than he does now.
Tazz also can't get into the litter box without help. He's been great so far about not going wherever he happens to be parked at the time, but it's another thing we'll need to keep an eye on - his skin could get irritated if it's dampened by pee a significant fraction of the time.
So, I'm glad it's not more serious than it is. There was a decent chance that the cause was going to be liver failure (he's, well, old, and he has mild renal disease already) or cancer (he's got a previously-quiescent mass on his pancreas, which could have metastasized onto his spine). A slipped disc, while massively inconvenient for him and his humans, isn't going to be a direct cause of death.