I have a pup with lymphangectasia. What I strongly suggest you do is to go to a board certified internal med vet. That is what I did when Cookie's protein levels were found to be terribly low in Dec. 2011. I also did a consult with a board certified vet nutritionist and I cook for Cookie every day. I am happy to say that she is still thriving! Here is a link about her...perhaps it will help.
http://www.yorkietalk.com/forums/sic...ia-update.html
While meds are important and they give more at the beginning, the specialist told me that recent studies indicate that diet plays a key role in the success of treatment for these pups.
Good luck and please keep us posted.