Symptoms of liver shunt may include excessive drinking, depression, weakness, poor appetite, frequent urination, vomiting, drooling, and a general lack of interest in activities. Puppies with liver shunt are also prone to frequent urinary tract infections. If you suspect that your puppy may have a liver shunt, observe him or her closely after they have eaten. A dramatic increase in the severity of symptoms is a sign of liver shunt. Your puppy may also exhibit unusual behaviors, such as running in circles.
http://www.yorkielane.com/Health/livershunt.htm
I have heard some report that head pressing is common for a shunt baby also seizures.