UTI causing litter box problems?

Chula, my 2 year old, is being treated for an UTI and I'm wondering if this could explain some odd litter box behavior.  It started up when she developed the UTI, indicated by the presence of red urine.

Basically she urinates inside and outside the box and I'm trying to figure out the pattern.  At first I thought I wasn't cleaning the box frequently enough, so I stepped up my efforts.  This isn't the problem.  I'll find urine inside the box as well as behind the box, next to the wall.  There is always a little bit of litter mixed in with it, as though she first uses the box and then squeezes out more outside, having tracked litter in her wake.   Today though she has barely urinated at all, and that is against the wall, although she still had clearly first been in the box, indicated by the presence of litter.

Has anyone else experienced a similar pattern?  Am I correct in associating this problem with the UTI or is it just a behavior issue?  I haven't had a chance to get her her own box yet but since she shared with her brother before, I'm not sure why this would suddenly become an issue.

When do I get worried about reduced urination?  I'm wondering if I need to give her fluids - maybe even take her to the vet?  She's been on the antibiotics for several days but I'm having a hard time getting them into her.  I've just finished watching several videos so hopefully will have improved technique tomorrow.

She's been very active today and seems to feel okay - lots of playing and cuddling.  She has a new toy she loves and seems to be happy and enjoying herself.

Sorry this is kind of long -  I really appreciate any feedback and advice people can give me.  I am getting worried about her.

Yeah, usually when cat have litter box problems it is due to uti. So i think you are correct associating the problem to uti

Thanks for the confirmation.  I kinda figured that must be the problem.

How high are the sides of the box? I ended up using a large opaque plastic storage container and cutting a hole in the side for my older cat because he started peeing outside of it when he had crystals. After watching him, I realized he started trying to go immediatly after stepping in the box and his butt was still hanging over the edge which splashed or just flat out missed. The high sided box caught that . And it was cheap! It does take up a lot of room and I had to put him in it a few times (old litter in the corner helped) before he realized to step in the hole and not try to jump in and out. If she's doing it coming out, it might not help though....

That's a great idea!  This isn't my problem but I love your solution.  

The box is enclosed, so she climbs in the front, uses it, then climbs back out and walks around to the back where she goes again.  Unfortunately she seems to like this particular new variation, even now as the antibiotic has kicked in and urine is back to regular amounts and apparently blood-free.  Problem is:  my joints don't take well to pulling the box out of the way and getting down on my knees to clean up three or four times a day.  My thinking cap is still on, but at least I am no longer worried about her.

Ok, that's a neat (?) trick! Double using huh.......

That box is in the knee hole under my bathroom sink, so he can't get behind it. Could you block off behind yours with some cardboard for now? Maybe put down a puppy pad or something so you can just pull the whole works out until you get her retrained? Maybe drop a few drops of some scent she doesn't like back there? *scratches head*

I've been thinking of ways to block access - I've got a box that might do the thick.   It's worth a shot - we'll see if she's so determined she climbs over the box to get to her new favorite place. 

Hadn't considered puppy pads or obnoxious scents - those are excellent ideas and might be the next resort.   Up until today when it was clear the antibiotic was working, I was focused on the infection - hoping she would go back to normal once she felt better.  I should be so lucky!  She's found something she likes and she's sticking to it!  I think it will help to scrub the area down with Nature's Miracle and make sure there are no enticing old aromas luring her back there.