Oh no. I'm so sorry to hear this.
Please go here:
http://pets.groups.yahoo.com/group/L...d_MVD_Support/
and join. This is very important. They can answer all of your question.
You really need to find out what her pre and postprandial bile acid numbers are. It could be extrahepatic shunt (outside the liver and usually operable with good recovery rate if done by a good doctor), intrahepatic shunt (inside the liver, not operable and rare for Yorkies), or Microvascular Dysplasia (small shunting, not operable but can live a good life on proper protocol).
If your vet says it is a liver shunt they will send you to an internist. They will want to do tests. They will probably want to do an ultrasound (be careful with this because they are hard to read and it has to be done by an expert so it could be a waste of money...I have heard if the doctor wants to do one make sure it is doppler ultrasound). They will also probably want to do a Scintography or Portogram. If they think it is MVD they will want to do a liver biopsy (Ellie just had one during her spay and did fine but she ended up not having problems...).
Please join the Yahoo Group. They will help you.