Some of use might read everything going on here for this cat, and get overwhelmed. B12? Zofran? Fluids? Baby food? Raw food? Binder? Does my cat need these things? Will it work for my cat too? Should I switch him to raw food? It can seem overwhelming, cant it? How do you know you are making the right choices for your cat?
So the first thing to acknowledge here is that every cat is different, and even for this kitty, it took a step by step approach to find out what worked and what didn't work. This person tried multiple foods to find out what really stabilized his cats body weight. This person has his/her eye on what is going on right now, and has an idea of what to think about in the future to ensure that kitty is feeling well and living as long as possible!
This is a learned skill that anyone can do with the right guidance. But what’s the first step? When you get barraged with choices or opinions start with the “big wins”. “Big wins” are what I call the essential details to get right. It can be a way of thinking (your psychology) or a hands on technique. Once you have those core things down, you don't have worry if person A is doing this, and person B is doing that, shouldn't I be doing this too?There are infinite things you could do.
Know what the big wins are, get those down, and you are far ahead of the curve with respect to your cats health.
So, other than getting that body weight stable and eating well, what are the big wins I can see for this cat?
The first is to recognize that his heart and kidneys work together and the success of one (or lack thereof) will effect the other. So this kitty has CRS. Cardiorenal Syndrome. This is a big deal for humans, but we don't talk about it all the time with cats.
What it all means is this cat is a custom hot rod. The millennium falcon. Bit’s and pieces have to be put together here and there to get true performance. Traditional techniques must be modified to suit this cat. It might not look pretty and seem complicated but it works.
So what if his heart was stable, but he really started to get dehydrated and his kidneys were having a hard time. And he really really needed some sort of fluid but we were worried about his heart reacting badly? You would have to “mod” his fluids. This person would talk to his/her vet about combining fluids types to create a very low sodium mixture that could be used with greater safety in this cat if required. So to answer one of the original questions “Is there a limit to how much of that fluid he can have?” - I modify the question and say yes, there is a limit to how much SODIUM he could have (which is really what the heart cares about), and if he is getting a bunch through fluids, you have to watch it and go slow.
So for this kitty, I would be always thinking that modification is the key, whatever challenge he was faced with.
The RAAS. There isn't enough space or coffee available to explain that term, and it will bore most people. It stands for “renin-angiotensin-aldosterone system”. Yes i know that’s boring, don’t click away - I’ll get to the point. CRS (cardiorenal syndrome) activates RAAS. RAAS is no good for both the heart and kidneys. It’s extra stress on both of those systems that are begging not to be stressed. It’s a catch 22 you don't want. So this person could talk to the vet about using a medication (Fortekor or Semintra) to cut out excessive RAAS. And watch that blood pressure too.
Big Win#3. Mod’ the food and add in Calcitriol.
Go with some time tested techniques to reduce phosphorous in the diet (these are called “binders”, and it doesn't matter if you are feeding raw, commercial, home cooked etc). If you can achieve that, then consider Calcitriol (vitamin D) therapy. This is a big win for this cat, because of the things we want to do for him we cant always do because of the heart condition. Many cats with kidney issues will have concurrent issue called hyperparathyroidism that further run their kidneys down. Calcitriol therapy can manage this without compromising the heart, further balancing this little kitty out. But the phosphorous has to be controlled first for this to work. This would be a “big win” that this person could talk to their vet about.
There are infinite choices that could be made for this kitty. What about this, what about that? I always start with the big wins!