Please explain my cat's odd behavior (and what to do about it).

In My Humble Opinion
1

In another thread, I had asked for advice on how to clean cat urine out of a rug. Initially, the advice was extremely helpful and left no trace of urine. However…

My cat has some degenerative pelvic disease that the vet can’t figure out. Her hips and hind legs are extremely weak, causing her to appear like the back part of her is walking on ice. She’s lost a ton of weight and she drinks a lot more water than she used to, so she pees a lot more than she used to. I brought the litterbox downstairs for easy access and dutifully clean it every day, but not only is she still peeing on the living room Oriental rug, but she actually painfully traipses upstairs to go pee on the bathmat in the bathroom. Why would she go through so much difficulty to go upstairs and pee on the bathmat?

She knows the new location of the litterbox, because she’s using it to poop. I’m at my wit’s end, because she’s pretty much destroyed my Oriental rug (it did really tie the room together) and my poor housemate keeps stepping in puddles of cat pee both upstairs and down (and bless his soul, not complaining about it). I’ve gone through four gallons of vinegar and 4 boxes of baking soda, constantly trying to clean the messes up.

Help, please. For the record, I have two cats. The older one (11 year male) is perfectly fine. It’s the younger one (10 year female) giving me problems. She continues to have the most wonderful personality a cat could have and never, ever does anything out of spite.

TR;DR: Cat has atrophied muscles. Poops in the litterbox, but continues to pee on the living room rug and laboriously climbs the stairs to pee on the bathmat. Why?

2

I’m going to throw out a guess: Cancer in her spine, affecting her brain, so she’s trying to do the right thing but not really thinking clearly. This is just a guess. It would explain the weight loss and the hip problems.

You need to throw the rug away and probably put a second litterbox upstairs (as well as ditching that rug,too) so that if she does make it up there, she’ll find the box for which she’s looking.

Poor baby. And I hate to say it, even if my guess is wrong, you probably should have the hard conversation with the vet about her pain levels and her struggles.

I hate to be the bearer of bad news but, well, that conversation is part of the deal.

3

I went through something slightly similar with my 16 year old cat about a year ago. Over the course of a week or two, her back legs seemed to lose a lot of muscle tone and then they became so weak that she could hardly walk and she was losing bladder control.

The vet did a bunch of tests and didn’t know what could be wrong. I was freaking out about kidney failure, having lost a different cat to it, but those tests came out fine. The only thing he noticed that was a little odd was that she had crystals in her urine (or something like that) which indicated mild bladder infection. He gave me some antibiotics for it and within a few days she was back to normal. I don’t know if it was the bladder problem or some other sort of infection, but she’s been fine ever since.

4

I second the idea of another litterbox upstairs.
Good that you’re cleaning with vinegar …
I think I’d try another Vet.