This lovely cat died last Friday. She had "Feline Infectious Peritonitis" [link] which became unmanageable during the last 6 weeks of her too-short life.
She was almost a year old. Too, too little time.
In her last weeks, her muscles had wasted away, her tummy became distended, she lost all appetite (except for cuddling), and finally, stopped purring.
The vet who originally let me adopt this wonderful cat (from a local animal shelter) is also the one who helped me end her suffering. The vet even let me hold the cat while it "went to sleep", so that her last moments weren't lonely or frightening.