I am sooo sorry to hear your puppy might have a liver shunt. My family and I have gone through this ordeal with our Yorkie, Tucker. He is a very large Yorkie, and no one suspected a liver shunt, but he had the EXACT same symptoms as yours. Most of the time, surgery is the only way, the defect is genetic. But we were very fortunate with Tucker, and are able to maintain him with medication and diet. I have posted before concerning his shunt if you would like to read it. Also, I have a link that will give you some good info. Keep us posted, and good luck
http://www.yorkietalk.com/forums/showthread.php?t=16530 http://www.yorkierescue.com/livershunt/research2.html http://www.vetinfo4dogs.com/dshunt.html