We just had our Liza Jane put down Thursday. Not a garage cat; she lived indoors all 15 years. She had a thyroid problem for many years, and it finally caught up to her.
I lost my little buddy Sima at 21 years old because her kidneys had shut down after a long time of thyroid issues (unknown to me). My current little buddy Meesha, was diagnosed hyperthyroid last September. I started her on Science Diet thyroid dry food. Last week I had her bloodwork results and she is back in normal range for thyroid function (on a scale of 1 to 10, she was at 11, now back to 4.7) which the vet tells me is a number less than five.
Hyper or Hypo thyroidism is common among cats of years. If your buddy is drinking or eating excessively and seeming to loose weight, loosing muscle mass, or even changing litter box habits, get to the vet and have their thyroid function checked.
Here are pics of my buddies Maynard and Meesha. Maynard is a Mackeral Tabby (speckled nose), got him at six years old from the local Humane shelter. LOTS of character, drags my cloths around the house. He's 17 now, been with me since 2008. Meesha is a purebred Siberian Seal Point, a $600 kitty. Siberians don't have the enzyme in their saliva that cause allergic reactions. She is a sweet little talkative girl now 15 years old.