I don't know if this has been posted about on here before, but I just learned about 2 weeks ago that my old dog has this syndrome. Many dogs have been unnecessarily euthanized who have had this disease. I urge everyone to read this article, and if your dog presents these symptoms, get a second opinion before euthanizing your dog.

http://www.dolittler.com/index.cfm/2006/11/20/pet.vet.dog.cat.pp.11.20.06

Wow, thank you for posting this.  I had no idea this happened with old dogs, it's very scary that she might have allowed the ER vet to euthanize him (not knowing any better as a good owner she might have done that to stop his suffering).  This is good information to know.