Minnie ( all black) has IBS and was having a bad week with colitis and looking poorly. I think she may have been constipated. She goes back and forth between constipation and diarrhea. I added colostrum (see my Cats and Dogs Naturally article) to her diet and it seems to be helping. My vet will send a glandular for intestinal issues to add to that.
Yoko (tan tabby) has thyroid issues and she seems to be developing some kidney problems. Thyroid irregularities can affect the heart, liver and kidneys. I have boosted her diet with Chica's (who has chronic renal failure) supplements and it seems to be helping. She is more active and less mopey.
Every morning the first one up walks through an obstacle course in the house of hairball vomit, puddles of frothy mucus, etc....yecch... and I don't' know who did what. This week it was more than usual so I was trying to keep and eye on everyone.
It seems like all is on track again today and everyone is doing OK for the time being! I am glad I can treat some of this myself with phone calls to my vet --- very expensive to run to the vet all the time.