If the vet suspects it's a liver shunt, it's very important that you cut out the protein that's not coming from the k/d...It makes their symptoms much worse. Protein's by-product is Ammonia which is supposed to be detoxified through the liver and then it goes to the vena cava, then to the heart, and through the circulatory system. But if the liver is not functioning properly or there is a shunt by-passing the liver, the ammonia is NOT detoxified and the ammonia goes through the whole circulatory system causing all these terrible symptoms that you are describing.
It's very unhealthy to keep giving him that much protein and could cause very scary seizures that could kill him. I don't want to sound harsh or scare you, I just want to stress the importance of not giving him that extra protein.
The reason I know all this is because my Miko has been through it. We've had to go through a lot with him and have learned so much.
Miko did have exploratory surgery and unfortunately the vet was not able to repair the shunt because he has either microvascular dysplasia or an intrahepatic shunt...Microvascular dysplasia has no cure, but they will usually put the dog on medication and special diet for life. Intrahepatic shunt is too risky to operate.
Miko is on a liver supplement, lactulose, and special hepatic diet to keep his symptoms away. He is such a healthy and happy yorkie now, and I love seeing him like this. The vet said that he should live a normal life with the medications and special food. Miko is the joy of our lives and I'm so happy that we have him
Here's a website that you can go to and find more info:
http://malteseonly.com/shunt2.html