This may seem silly to some, and for that I apologize. However, I don't know why this never occured to me before.
I have a cat who is about 12 years old now, and for the majority of his life has been classified as "grossly obese" by his vets. "Tiggrr" flat out refused to eat the "prescribed" weight loss cat foods the vet gave him, so I fed him what he would eat... 9 Lives, etc..
Well, in the past few months I noticed 'Ol Tig was constantly eating, he stopped using the litterbox and peed where ever he stood, and he drank gallons of H2O. Hmmmm... The three P's.
Also, and this was the most alarming, he showed signs of neuropathy... Walking almost on his "knees." (use your imagination)
I went online and googled "cats and diabetes" and what do you know? There are a myriad of websites devoted to this. I read up on it, and took Tiggrr to the vet, telling the vet what I suspected. Guess what? Tig is now on 6 Units of insulin daily. Despite his distaste for it, he is on a special diet, and has lost about 10 lbs. Beleive it or not, he is a new cat! The lizards in our yard are toast! He pounces, jumps, plays, and acts like a kitten again.
Just a reminder to all of us that our nursing skills can indeed cross species, and help every special member of our families.