Here is the website everyone is sent to in order to read up on Dr. Tobias' articles:
Portosystemic Shunts FAQ
Over on the left side of the website are other links to learn still more.
I'm sure sorry to hear that little Milo has an elevated level but there are reasons it could be nothing. Just watch for abnormal behavior and the symptoms and have his Bile Acids checked if he starts to show signs of liver shunt or MVD.