Cat being sick, can't determine cause. Any help?

As your cat is an older cat it sounds like he could have Hypothyroidism especially as he is losing weight despite eating quite well. Is he sometimes extra active at times, more so than usual as this can also be a symptom of this condition. This illness can be discovered by a vet through checking his heartbeat and blood pressure, maybe you could see a different vet too for a second opinion.

I feel that your cat maybe quite poorly as 15 is a very good age. I would imagine he is inoculated and wormed. He may have teeth problems and perhaps not digesting his food properly but i would hope the vet checked this before hand. Is there anything outdoors that he could be ingesting to make him ill? Its worth checking. I am concerned that he has lost weight as this can be a sign of some sort of tumour but this should show up in a blood test. He may have also developed an intolerance to what he is eating with age so you may need to talk to a professional to see if it is a dietary thing.

Well if you have indeed done all the blood work there is to do. Then xrays and ultrasound should be next on the list. So hurry and get those scheduled or switch to a different vet who is willing to keep looking for an answer. I would in the meantime feed the cat all the food it wants b/c obviously there is some underlying issue there. Good luck with your kitty!

At 15 he should not be really old yet.

Bloodwork cleared any renal issues? Kidney issues? Thyroid issues?

Has the urine been checked for diabetic condition? Does the cat have any cracked/broken teeth, mouth ulcers or throat growths? All these things cause rapid weight loss in a cat.

If they've all been checked, get a copy of the cat's results and take them to a second vet for a second opinion--the first may be missing something subtle.

Loosing weight is normal for his age. You might want to try dry and wet food for sensitive stomachs. You can get at the Vets. to see if he stops getting sick. Or try kitten food? I had 8 cats at once, my oldest was 28 when she died. With our love and care our cats are living longer, their bodies are becoming more sensitive to everything with age. Keep cat box clean, vacuum around the house more, take your shoes off when you come into the house, TRY different things.

Hopefully your vet has been able to offer suggestions. I would try different foods to see if he can tolerate them. You may even have to cook food for him yourself such as chicken and rice. Something gentle on this tummy.

Well i'm sorry to say but i think your furry friend is dying of old age.

the life expectancy if housecats is 13 years. your cats a survivor. i have a 6 year old cat. she already considered middle aged. sorry but it just all points to that

:(.