10-year-old dog not well - lethargic, panting, weak. Potential Cushing's?

[poorlydoggg]

Our 10 year old Yorkshire Terrier isn't well. We took him to the vets last week as he had started weeing overnight and he does seem to drink a lot of water. In a matter of weeks he had stopped being able to jump up the sofa and he has been panting a lot after any exertion. He had a full blood test and a urine analysis and they think it is potentially Cushing's disease.

He had the ACTH stimulation test and we're still waiting for the results but he came home from the test like a different dog - he is very lethargic, won't eat much (not even treats) and is very quiet. He hasn't weed overnight for a week now, so it's like the original issue that we took him to the vets for has resolved but in the space of a week he has gone rapidly downhill with something else? The day before his ACTH test he went on a normal walk, and yesterday he wouldn't go at all and he is walking around so slowly. He wasn't sedated.

Does anyone have any insight into what it could be?

Could well be Cushings but as he seems so poorly I’d be taking him back today

If you haven't today, I think you need to take him back to the vets tomorrow. He sounds like my dog who has addisons (ie the opposite of Cushings). I'm not a vet so don't know, but not eating, lethargy and such a sudden change needs a vet visit.

I agree with @noctilucentcloud , this sounds like the symptoms my Pointer had who was then diagnosed with Addisons disease

My dog has Addison’s and was lethargic, stopped eating, wouldn’t play.
She lost 7kg in a week.
Vet did bloods but didn’t wait for results before starting treatment or she said dog would die very soon.
The symptoms can come and go and be mistaken for other illnesses.