Hi, Welcome to Yorkie Talk. I am sorry that your lil girl is having a problem, and hope that things turn out ok for her. Many members on Yorkie Talk have been in the same situation, and we are all here to support you.
In fact, my Tiki was also suspected of having LS when she was 7 months old, following pre-spay blood work. I know how terrifying that is, and how frustrating it is to go through the various tests. First of all I want to say that although it is scary, it is not a death sentence. If there is a shunt it likely can be repaired, and there is a possibility that it is not a shunt, but something else, like other toxicity, or MVD (microvascular displasia) also known by a new name I can't recall.
My Tiki turned out to have MVD, which is managed medically by diet, and I'm happy to say she is doing just great at 6 years old.
Here is a link to a brochure full of great info about liver diseases which is so common in Yorkies. It is a good overview of liver disease and treatments, and is written by Dr. Tobias, of Univ. of Tennessee, who is the top Doc in dealing with liver disorders.
http://www.vet.utk.edu/clinical/sacs...NAL-201304.pdf
I'm praying all will be well for your little one. Keep us posted on her status, and do come here whenever you need a hug. Many of us have gone through this, and we truly understand how stressful it is.