Have Cat Questions? Ask a Cat Vet Online.
I am sorry to hear you are worried about your cats. I am a veterinarian and will do my best to help. My name is Rebecca.
Gosh, there are dozens or more reasons for a cAt 16 or 18 years old to lose weight and not eat well. Cats do not just stop eating, it is a symptom that there is illness or pain somewhere. Since cats tend to be secretive about not feeling good, sometimes their appetite is the only outward sign that something is wrong.
If these were my own cats, I would begin with a good physical examination: listen to the heart for a murmur, take their rectal temperatures (less than 100 could indicate dehydration or kidney disease, over 103 would be a fever), feel the lymph nodes and internal organs, check to see if their gums appear pink or pale, etc. Often the exam give me a clue what is wrong, and what my next step should be.
Your cats are telling us that they do not feel good. Having your vet check them over is the best place to start. Let me know what other questions you have. Rebecca
How are your cats doing? Can I help with anything else?