Dog retaining water
My parents just lost one of their dogs in April to cancer (they think). It was quick. He was diagnosed with a tumor and three weeks later he died. His "sister" is 12 years old and when she was a puppy she was hit by a car and that impact broke her pelvis. She was fine for years but a few years ago she developed arthritis and the vet put her on some type of medication that she has to be given daily. The vet warned my parents that the medication would damage her liver and kidneys and possibly her heart. After her "brother" passed away she seemed to be depressed at times. About a month ago she wouldn't eat or go outside for two days. My dad did not think she would live through the night.
I drove up to their house to see her (they live 2 hours away) I arrived to a totally different dog that they had described. I got her to eat, to go for walks etc. She was her old self. I went to visit her again last week and she was even more energetic (we went for FOUR walks) and she ran around and seemed to be doing so much better. Well two days ago she started not wanting to go outside and yesterday my parents noticed she was retaining fluid and her back legs were all swollen. They took her to the vet last night and the vet said it could be liver problems, gave them some lasix and an antibiotic and some pain killers. Vet did not run any blood tests or anything. Any ideas what this could be?