Suggestions for how to narrow down diagnosis of GI issue?

[mycatsarecalledfood]

Hi! I am trying to figure out what is wrong with my cat (3yo spayed female) since my vet is not sure. I'm wondering if there might be a less expensive way than an ultrasound to narrow down a diagnosis given that whatever is wrong with her is likely to be expensive to treat, so I'd prefer to save a few bucks that may be applied down the road to helping her feel better if I can. The two most likely suspects at this point are IBD and dry FIP, but it doesn't look like a very typical presentation of either.

We have raised her since she was born to a stray cat in our back yard. Mama had 7 babies, but 2 died suddenly at 6 weeks of unknown causes. Basically they suddenly dropped a bunch of weight and crashed very quickly. Working theory was that they were weak and sickly to begin with and intestinal parasites were the last straw, though FP was ruled out. We found homes for Mama and 4 of the surviving kittens and kept the 5th. Our kitty liked to eat and was very chubby, very friendly and talkative.

She began to lose weight about a year ago. We took her to vet in May since by then she'd gone from being endearingly fat to worryingly skinny, followed vet's suggestions to switch out foods. Sometimes she seems to do better for a bit right after a switch, but the problems always come back. Since one of our other cats has a sensitive stomach they eat fancy grain-free kibble and occasionally some decent quality wet food.

Symptoms:
weight loss
anorexia
sometimes she seems hungry, but she often vomits after eating (this has increased lately)
Over the past week, she hasn't been acting like herself: less talkative, more clingy, less playful, lethargic. Also has had diarrhea for a few days.

Monday brought her back to the vet and she'd lost almost a whole pound since May, and she's small to begin with - now down to 6lb, 6oz. Got lots of bloodwork done, most of it was normal: blood count, kidneys, protein levels all normal, FIV and FeLV were even retested to be safe and were negative again.
FCV positive at 1:400 and at 1:1600, but A/G is 1.2 and I found some journal articles suggesting that A/G >0.8 makes FIP less likely. (I'm a doctoral student with access to research databases and tend to try to manage stressful situations by researching them to death, lol.)
Platelet count is also a bit high (700).

Suggestions for any other tests we might look to for a clue would be deeply appreciated. Thanks!

 

[FeebysOwner]

Hi. From everything I've read on this site, through research, some personal experience, etc. there is no one pathway that is the most direct, successful, least expensive route to go in determining IBD (or dry FIP, for that matter). The most 'successful' way is through biopsy, but even then, I am sure most vets would recommend a series of tests first - more than likely including ultrasound, along with some non-standard blood tests (pancreatitis, B-12, are just a couple). And, depending on what they would 'see' in an ultrasound, it is possible that they could recommend an endoscopy with a tissue collection for testing the cellular structure. If the inflammation is not seen in the area that an endoscopy would be of benefit, then you are back to biopsy. Additional non-invasive testing can be done during an ultrasound, called a fine needle aspiration (FNA) which collects tissue for analysis that might preclude the need for an actual biopsy.

An ultrasound would look at the intestinal tissue searching for thickening in the intestinal wall and inflammation. But you would more than likely be told that is not conclusive, and the odds are the recommendation would be to treat your cat as if it were IBD and give her Prednisolone - assuming other conditions were not revealed through the ultrasound and/or the other testing.

If I were you, I would use your research skills and start investigating the kinds of afflictions that can look like possible IBD - and, maybe this article would be a good place to start. Disorders of the Stomach and Intestines in Cats - Cat Owners - Merck Veterinary Manual (merckvetmanual.com)

Once you can collect your thoughts, asking questions - in various hypothetical situations - about the steps that would be most appropriate would be the next thing to do, so you can assess the options and related costs. It might be valuable to consult with an internal med vet, as they could more easily rule out certain conditions and focus more on the most likely ones.

You will likely get tons of responses here that will lead you down numerous paths related to what others have experienced while their cats were being looked at for possible IBD. There will be other tests mentioned as well in their journeys to find a conclusive answer. From what I recall, most went with treatment without really ever definitively reaching an IBD conclusion.