We had a dog maybe 40 years ago that was getting thinner above the diaphragm and fatter below. We knew it 19 rather had awas time and when we took him in, an x-ray showed his abdomen was filled with fluid. My brother had a 19 year old sheltie that was slowing down. One day, we noticed the floor he as laying on and his fur all over was drenched with sweat. It wasn't urine and dogs only sweat through through their paws, so we knew it was the end.