It is rare to find true yeast in cat urine, but it is concerning when present. Usually there is an underlying problem that is predisposing the cat to this such as an immunosupressive disease (making immune system not work well), diabetes mellitus, or inability to completely empty bladder (if present usually due to spinal trauma). This means if it hasn't already been done, your cat needs thorough lab testing (complete blood count, chemistry profile, thyroid check) and screening x-rays of the bladder to rule out stones. It also probably would be indicated to do a brief ultrasound of the bladder to be sure there isn't a tumor in the bladder.
Treatment for this problem usually starts with oral antifungal medication. Cats tolerate itraconazole the best. Usually requires therapy for at least 3 weeks and then a recheck urine. If the yeast is still present or the cat is still symptomatic then the urine will need to be cultured (fungal, not bacterial) to determine the type of yeast present. It is more complicated to do sensitivity profiles on fungi; this involves sending to a special lab and requesting specific types of antifungals that your vet wants tested. If oral medication fails, then flushing the bladder directly with an antifungal is the next step.
Best of luck.
She is very small 3 lbs and is crying all the time now.
She does not travel well at all. It takes her days to get over taking her to vet.
Is there something I can do right now to make her more comfortable.
How many of these test do I put her thru and what ones can all be done at the same time.
Should I be thinking about the chance that there isn't allot that should be done for her because of her age and attitude? I want to do what is best for her but I also do not want to cause her more pain just to keep me happy by having her around for a bit longer.
How do you know when it's the best thing for them put them to sleep.
Of course money is always a question but I will do what ever it take to do right by Cally.
I think it is well warranted to have at least one more trip back to her vet. At that visit it is easy to get some blood to send off for the screening tests and your vet can advise you if they feel they should recheck her urine to confirm the yeast is still present. Then at that time you can discuss what medication would be appropriate for her. This is an uncomfortable problem that can certainly improve with medication.
At home, make sure she continues to eat and encourage her to drink. There isn't any over-the-counter medication or remedy that will help this problem.
Regarding when is it time to consider stopping or putting her to sleep, this is a very difficult question and a very personal question. Remember that this yeast in the urine may just be a sign that there is something underlying that may be quite significant going on and that may be her primary problem. Rarely is yeast urinary tract infection a primary problem. I usually recommend when considering euthanasia, really assess how she's doing. How is her quality of life? Is she still eating, making it to the litterbox and social? Those are usually the most important things for a cat to be doing well. If she's lost one or more of these aspects of life, then her quality of life is diminishing.