So, I did get Nova in to the vet this afternoon. (Or yesterday afternoon, maybe. Since it's past midnight now, and thus time for another post.) Poor thing. He isn't just backed up, he's very backed up, and he has a urinary infection. Which he quite handily provided a diagnosis for, as he peed on the scale a little when they went to weigh him, and the veterinary assistant immediately looked at it and went, "Oh, there's blood in the urine!" (Which I wouldn't have been able to tell, myself. It was slightly discolored, but not noticeably red.)
Anyway, they're keeping him overnight, at least, and will give him antibiotics, and an enema, and some fluids. Poor baby. With luck, he'll be looking up a little in the morning, and I'll be able to take him home when I get off work. But we'll see. He's so old, and in such poor shape generally, that it always seems possible to me that any blow to his health might end up being the one that knocks him out for good. Which... well, it worries me, but given that I'm honestly surprised he's made it this far, my feeling about such a possibility is more resignation than fear. And he's in good hands for the moment, at least.