I took him to the vet today because I noticed something funny was going on when he purred. He would dry heave, and then have difficulty breathing. I noticed a few days ago it happened once when he wasn't purring, so I took him in.
The vet isn't quite sure what's wrong with him yet, but we do know it's life-threatening. He has a lot of fluid in his chest cavity. When she tried tapping him, it didn't come out, so she thinks it's a heart problem. He has to stay overnight while they pump him full of diuretics and try to get the fluid out of there so they can get another X-ray of his chest and see if the heart is also enlarged, or what.
It doesn't look good.
His kidney numbers were also worse, and I'm worried the treatments to try to get the fluid out of his chest will cause more kidney problems. The vet says it's unlikely that there will be any rapid and permenant problems because of this, though. (And honestly, if there is, it can't shorten his lifespan that much more.)
I'm supposed to call tonight around 7 or 8 and see if they've been able to take a clear picture of his heart yet. From the sound of things, if I hadn't brought him in today, he probably would have died from a heart attack within the next few days.
We don't yet know if there's a tumor or if it's congestive heart failure or what. I don't expect him to live more than another year though, if that. I'm really bummed out. Right now, I'm just hoping he makes it through the night. We can't make any plans about what to do for him in the long term until he gets past this problem with the fluid in the chest cavity.
The vet showed me the X-ray, and it was pretty much all solid white. I couldn't believe it. You couldn't make out any cat-related structures other than his ribs. The vet was shocked he was breathing as well as he was, and that he was actually still eating, etc.
I'll keep everyone updated.