Hi, I will pray for your baby. I had a little boy yorkie a few yrs. back that had some symptoms two vets could not diagnose. My husband finally took him to the Texas A & M Veterinary School. They hooked him up to EKG equip. some type of brain wave stuff and a bunch of things overnite. They were able to find the problem. It was not very expensive either.
Is there a research veterinary school near you by any chance? They will have the latest equip. and pursue avenues our regular vets are not equipped to do. I hope you find some answers. Hugs.