Please don't listen to anyone who tells you to put your cat to sleep over a CRF diagnosis with a creatinine of only 3.2. That's ridiculous. By the way, treating diabetes is far more difficult and time consuming that treating CRF. I wish Max had only CRF! That would be a breeze.
Have you been to Tanya's CRF site:
http://www.felinecrf.org/index.htm ?
What I have learned since my cat was diagnosed with CRF is that cats who are properly cared for can live a long time, and be very happy and comfortable. Treating CRF is far less expensive than treating diabetes once you get the cat stabilized. (My cat has diabetes, too, which makes the hydration issue all that more difficult.)
Giving subcutaneous fluids can be a detriment at times, as Lisa said. Just like with diabetes, a vet will say, "Give x amount y times a day or z times a week," and send you home. You don't find out until later that the vet was treating the numbers only, not the whole cat, or that the vet has a generic treatment plan for all cats with CRF. Part of it is, of course, that vets don't know if you are the type to take a proactive approach or the type to just wing it. They just have to hope you'll bring the cat back for more tests and they can catch any complications caused by what you have been doing to the cat. I suggest you read Tanya's site, and learn about all the issues so you can be active in the cat's treatment.
BUN can also be elevated by mere dehydration. What happens in CRF is that the kidneys cannot concentrate the urine as well. Instead of peeing only the waste product and a little water, the cat is peeing a lot of water, too, just like with diabetes. You may notice that the pee doesn't smell nearly as bad as it did before, and that there is a lot of it. If the kidneys were working well, a lot of that water would be retained for the cat's body to use again. Cats evolved this way because they were desert animals. The severity of your cat's CRF cannot be assessed until you get the cat hydrated and stabilized. Then, the BUN and creatinine numbers may go down. My cat's numbers did.
Take this to heart: your cat's numbers are not that bad, number one. Number two, do not be alarmed that the creatinine number you see means that your cat may have lost 60% or 66% of it's kidney function. Apparently, a cat who is otherwise healthy does just fine with only 33% of kidney function. It is very common for the creatinine test to find CRF only after 60% of function is lost, but your cat can get some of the function back if you keep him/her hydrated, feed wet food only, and watch out for any illnesses or recurrence of diabetes, and are careful to give fluids only when necessary -- not on a set schedule that does not take into account the cat's actual hydration.
So how do you know if the cat is in need of fluids? That's the million dollar question. I'm trying to keep my cat hydrated without over-hydrating him which will tax his kidneys or risk high blood pressure if he has an undiagnosed case of that. I can't pay for a BUN test to be done every week.
Tanya's site shows you how to check hydration by pulling up on the cat's scruff, and I'm sure there are a number of youtube videos that will show you how, too. I am hoping that I will learn over time how much fluid Max needs on a weekly basis by logging hydration checks and all the times I give fluids. Even with diabetes, 100 ml twice a week turned out to be far too much. It's probably because I'm feeding wet food only, and the vet didn't take that into consideration.
As for the cat fighting you, there a lot of videos on youtube and a lot of information about how to do it right on Tanya's site. You can learn to do it in a way that is less painful and difficult for your cat and you, and you will. Don't worry yet.
Good luck!
