In fairness to your vet FIP has always been and still is a very tricky condition to get to the bottom of and in fact those fresh out of college may have better knowledge on the current thinking than someone a bit longer in the tooth! I know you’re not being bad to your vet though and there is no harm in trying to find out more, especially with such a worrying condition and such a young cat.
As vets these days we are very used to being able to pretty much cure a great number of things or at least have it in our power to find out what is going on and know why we can’t do anything about it. FIP is a problem because it is caused by feline coronavirus which many cats come into contact with at some time or another but only a small number ever get affected by this disease. As with many viruses you can test cats to see whether they have come into contact with it but this is where the difficulty lies. Because many cats encounter the virus and carry the virus without ever having any problems and never developing FIP the test is virtually useless for diagnosis because of all the positives.
FIP stands for feline infectious peritonitis and causes a wide variety of signs such as inappetence, weight loss, fever, jaundice, vomiting, diarrhoea, and respiratory signs. It can also cause neurological signs and problems with the eyes too, particularly in the dry form of the disease where no fluid is produced. So as you can see it can appear like a massive range of diseases without a definitive test.
Sadly, FIP is fatal and is often diagnosed post-mortem. I have only seen a handful of cases in 13 years but have never come across one that survived. The other awful thing about it is that, as in your case, it nearly always strikes young cats, often younger than Marty. It tends to be more common in purebred cats because the virus thrives in multi-cat places such as breeding colonies. I don’t know whether Marty is a moggie or a pedigree but it will make little difference in the long term if he has he disease.
So what can you do? As you may have guessed, very little if it is indeed FIP. Steroids and antibiotics can help and some people try a treatment called interferon which seems to help in some cases. All these things are really only palliative though and can help with the signs until the inevitable happens. You mention that Marty has had tests involving Glasgow uni but don’t say which ones or whether he has actually been referred there. Ultrasound of the abdomen and chest and x-rays can sometimes help with a presumptive diagnosis but often fluid examination is one of the biggest pointers which you say he has had done. Exploratory surgery may also offer an insight because FIP tends to leave fairly distinctive fibrin tags on the organs. The problem with this is that, again, it is not truly diagnostic and very ill animals are not brilliant candidates for surgery.
So, all in all, I suspect I haven’t helped much but for FIP there is little to offer even now. If he is rallying really well and gaining weight then it may be worth considering referral if money allows in order to try and get closer to a diagnosis. Alternatively you could look at it this way; if he has FIP he may rally but ultimately fade in which case you will have your answer. If he has a curable viral or bacterial disease he may well just carry on recovering in which case he almost certainly didn’t have FIP. I really do feel for you. Losing a young animal or even contemplating that is just horrible. I hope I’m wrong and I hope the pointers are all wrong but I think with the signs you describe, his age and the presence of fluid on the chest I think you should be prepared for the worst. Please get back to me if you need anything else, please let me know what happens and thank you very much for your contribution to the site costs.
