Older cat stopped using box

[mandie0406]

We have an older cat (he'll be 16 this year). We've had him since he was about 6 months old. We also have one who will be 11 this year (had him since he was about 6 weeks).
Our older cat has pretty well stopped using the box. On the rare occasion that he uses it, he doesn't cover it up !
The younger one will actually go cover it up for him...
He uses my daughters floor for a bathroom. If we lock him up in a room with no carpet, he'll use the box. We went away over the weekend, and put him in the room off the bottom level that isn't carpeted and NO messes when we got back. But, if we don't lock him up, he uses the carpet. He's never done this before. No change in food...no new animals...I don't understand it. I do NOT want to have to put him down if he's not sick...but we can't keep locking him up and we can't keep letting him poo all over the floor...
Please help if you have any suggestions...

[opus88]

heres some info on FLUTD....could also be diabetes or hyperthyroidism so its very important this guy sees a Vet ASAP.

http://healthypets.mercola.com/sites/healthypets/archive/2010/05/19/check-this-first-if-your-cats-elimination-habits-seem-to-change.aspx

[opus88]

this poor old fella needs some medical attention, when they stop using the litter box or other different behaviors its b/c they are try hard to tell you something is WRONG something HURTS....at his advanced age I would sure get a urinalysis on him, its very common for male kitties esp as they age to get FLUTD...urinary tract problems, when it hurts to pee they also associate it with hurting to poop..any litter box action!!!
also get a blood chemistry done, he could well be into CRF or chronic renal failure. you have to find out WHY he is doing this and get him some help.
if he is on dry food, change right now to wet...older males in particular need all the water they can get to help with their bladders...
good luck to you both, please keep us informed.♥