It can be overwhelming to have a cat with a hyperthyroidism diagnosis. Read on to find out 6 new things to know about cat hyperthyroidism and how to deal with it. You realized that your pets’ coat has been looking pretty rough these days. He’s been eating loads, but they’re weight is going down. They are agitated and crying in the night unexpectedly, and when you go to empty the litter box, it’s deluged with urine. It’s obvious its a health problem, so you take furry to the vet. A blood test shows they hyperthyroidism. Now, what do you do about hyperthyroidism in cats?