3 week old puppy gagging, eating problems

Question
I have a litter of toy schnauzers. they are 3 weeks old. one is having issues. she is 181 grams. Her litter mates are about 450 grams. She is not skin and bones. She has a puppy belly on her and has been gaining weight. i have been supplementing her with milk replacer. When she eats she gets very girgly and sometimes some milk bubbles out the nose. She does not have a cleft pallet. She has been examined multiple times for one. Today when trying her on food she ate it up and then acted like she was choking and gagging for 10 minutes. Gave her a bottle and she continued to do that. There was nothing stuck. Stuck my finger down and it was clear. She does this each time.  Food is very runny and should not be choking her. Have taken her to the vet. She has been examined many times but the vet was not very helpful. I am leaning towards a larynx problem.  I guess my question is if it is a larynx problem should I put her down now or wait and see what happens as she grows. Could it be because she is so small and if she grows the problem will reside? If it is a larynx problem what are the options as she gets larger if any? Thanks in advance!

Answer
I don't know why the vet would have been less then helpful. Did he do any kind of an xray on the puppy to see if there is an issue with the esophagus?

There are a few conditions that can cause this kind of urping up of food but it doesn't normally show up until the puppy is eating more solid food between 5-8 weeks of age.

It is called a persistent right aortic arch or PRAA and it happens when the vessel around the esophagus that is supposed to withdraw and shrink when the puppy is born doesn't- and it becomes a stricture around the esophagus. It is very uncommon but not extremely rare. It doesn't involve the larynx at all.

You can read about them here:
http://www.peteducation.com/article.cfm?c=2+2096&aid=870

Other problems with eating are mega-esophagus, tracheo-esophageal fistula, atresia, diverticulum, heterotropia, and stenosis. Most of these are pretty rare. I don't know how big this puppy is but you might want to try and get an ultrasound of her digestive system or at the very least a barium xray series to see the extent of this defect, whatever it might be.

Only then can you determine whether or not she needs to be put down now or if she has something she might out-grow or that is correctable.

I hope it's one of those. Please let me know how she does and what you find out.