FIP without fever?

[mummyhaschangedhername]

So a bit of a long one. My mother's cat started losing weight, no other symptoms, was tested for FIP which apparently was negative. He eventually kept losing so much it was horrendous. He had scans and bloods several times and nothing was conclusive or even particularly indicative of anything. He started having loose stools and blood in his stool. Eventually he became lethargic and there was nothing left to do but for him to be PTS. 😢

That was the beginning of March, his sibling (same litter, birmans) started to lose weight too. Took him to the vets today, she took bloods and called and said she is 98% sure it's FIP, and will be dead within the month.

I realise it doesn't sound good at all, but she has no fever (neither did her brother), her only symptoms are significant weight loss, irregular and increased pulse, and vet said she is anaemic. Honestly to me it sounds more like bowel cancer, but really nothing fits with what I've read with FIP, but I realise by knowledge is based on like 15 minutes on the internet and I don't disbelieve the vote who seems great but really it's life and death so I feel it's only right to second guess when it doesn't seem to fit.

Anyone know anything about FIP? TIA

From my experience FIP doesn't seem to be linked to fever at all. I'm not a vet though. Weight loss, diarrhoea, even jaundice (as in the case of the cat that I brought in two days ago) all seem to be common symptoms. I've never heard fever referred to and the vets haven't taken temp as part of diagnostic for it. As I said though, I'm not a vet and could well be talking bollocks.

Thanks @thecatneuterer ... it's just what I read online. I guess it could be then. Was it your own cat that has been diagnosed with it? If so I'm very sorry.

Vet also said it was unusual in house cats but then online it says it common in homes with several cats (my mum had 4), so I don't know. I guess I'm just clutching at straws but then the alternatives aren't great either.

FIP most commonly occurs where cats have been stressed and the regular cornavirus ( which causes vomiting and diarrhoea) mutates into the FIP version. Because it is a mutation there is no definitive test for FIP. Increase goblins can suggest, protein electrophoresis on blood can also suggest as it divided the globulins into different types.
Has/did either cat have ultrasound scans and then exploratory surgery to obtain intestinal and liver biopsies?
Our practice work up for such cats would be blood samples, imaging ( ultrasound and x-ray) and probably exploratory for biopsies.
Bloods would include FeLV and FIV as FeLV can give many of the signs, but I would be considering non-FeLV lymphoma as a distinct possibility which would be suggestive from bloods ( low lymphocytes), but diagnosed in biopsy,

Thanks @Lonecatwithkitten - scan booked for Tuesday so I guess we will know more then. They don't seem to be suggesting further tests (least they have not mentioned it right now). I guess the fact she lost her brother recently might have caused stress.

Vet now thinks cancer of the kidney. She has seen a mass. No signs of FIP now which is a relief. My mum now needs to decide how to proceed.