Hi, Please bring your senior dog to the vet for bloodwork. The symptoms you have mentioned, along with the dogs age, remind me of the same thing that my 15 year old yorkie was doing. She was diagnosed with kidney disease. Decreased appetite and trembling are both signs of kidney failure.
Your dog may or may not have kidney issues, but the trembling, (shaking) you are describing, is a sign of pain or discomfort. Your dog really needs to be evaluated by a vet. Please insist on bloodwork to determine your dogs kidney and liver functions. ALL Senior dogs should have these evaluations done yearly. Please get him to the vet ASAP and let us know what you find out.
Best wishes,..Connie
You need to get him to his Vet ASAP.......Shaking is a sign of pain......Pain will lead to not wanting to eat.......Please, don't wait any longer......He needs to have treatment.......Good luck, Karla