Well the gastric emptying scan is a test where they look to see if the food is being properly moved from the stomach into the small intestines. For the test they will have her eat a small meal, usally eggs or oatmeal that is laced with a radioactive dye( it has no taste). then she will go under an xray machine and they will watch to see how long it takes the food to leave the stomach. Someone with gastroparesis, well the food will sit in the gut and there will be little movement. That is how they diagnose gastropareisis. The symptoms of gastroparesis are feeling Very full after only eating a small amount, bloating, nausea, and vomiting and stomach pain. Symptoms can vary with each individual.
Usually with crohns they do a colonoscopy and a biopsy to diagnose it. Did she have positive biopsies that indicated crohns?
It seems like she definitely has a motility issue of the gut. If in deed she has gastroparesis, the meds they use to treat it are reglan( that is used here in the United States.), and also there is a med called domperidone( this is popular in Europe.). I have had motility issues in my upper gut before and took domperidone. It is much safer and a less side effects than reglan. I had to order mine from New Zeland though as it is not FDA approved here in the US. If you are from Europe, you can likely get it over there.
Also when she eats, does she eat easy to digest foods? I know when I was having a bad time, I ate like baby food. I mean I put stuff like vegis( well cooked) through a blender and did ok. I also ate very small amounts at a time. I mean eating a bunch of small meals throghout the day was easier to handle. I did ok with mashed potatoes, pureed vegis, easy to digest meats like chicken ( roasted) and turkey, fish etc... But it has to be mushed or at least chewed very very well. I am not kidding, I use to chew my meats until they were liquified in my mouth. It is just easier to digest then.
I am so sorry she is sick. I have a feeling the doctors have NO clue what is wrong with your daughter, or at least is sounds that way. It is like they are just throwing a bunch of names on everything.
I would ask for the gastric emptying scan to see if she is digesting her food. I mean when she vomits, is it hours after she has eaten or right afterwards??