wemple2, my yorkie is not malnourished either or underweight at all
He is a good 11lbs and he has a liver shunt. Please don't let your vet tell you that your baby can't have one because he's not one of those TINY yorkies. That's a complete misconception that vets who don't have much experience with liver shunts have... If you request a bile acid test, he should do the test. If not, I would suggest going to a vet that will address your concerns.
Miko was diagnosed at around 8-9 months...But he had had it since he was a baby...We took him to the emergency vet when he was a puppy (14-16 weeks old) because he was having seizures and we wanted them to check if he had a liver shunt, but they told us, "No way, he's too young, that's not possible" They told us they did not want to do that test because it was a waste of money!! Well, we believed them, so we didn't do the test that evening. They also told us that nothing could be done for his condition and that he probably wouldn't make it through the night...It's been almost 3 years now
We went to a different vet and ended up finding out that he in fact did have a liver shunt...