Hello,
I am so sorry to hear about your Yorkie. I have a 3lb 1oz "Tiny" yorkie and have had many health issues with her. I too went through what sounds as though is the same symptoms that your yorkie had.
I need to get my file, so that I spell it correctly and give you the information about the problem. It was an intestinal/blood problem and I was lucky since she is only 5 years old and the vet told me that she had a 20% chance of making it. Thankfully, she did, but she is now on a special diet, Hills Prescription Diet and is doing fine so far.
The best way of course to know for sure, is to see the results from the UGA next week, but I will reply back with the information I mention.
Again, I am so sorry for your loss. You must be very "good pet owner" for your Yorkie to have been 11 years old, since depending on their size 11 is considered old for a Yorkshire Terrior.
I will reply as soon as I can. Thank You, Tammy