You should get her to a pediatric gastroenterologist and have her tested for Strep of the bowel. My daughter had this and it took forever for them to diagnose it. Good news is that its easily cleared up.
Go to a pediatric allergist, our son was having nasty bowel movements and discovered he was allergic to soy. It may take a while to find the right doctor, but don't stop until you get an answer. Good luck.
Do you have a regular pediatrician? Taking her to a variety of doctors and the emergency room isn't really the way to go for this - seeing her usual ped is who should be helping you.
Best wishes.
Hi, my son is now 7. We went through the same thing. He has been constipated severely his whole life. At one point it was so bad that in an ER they gave him 4 enimas and nothing happened. I added more fiber to his diet. At around the age of 4 we took him to a Gastro doctor and after some testing we found that he has Celiac Disease. If you are unfamiliar, Celiac is an autoimmune disease in which the person cannot have anything that contains wheat, rye, oats, or barly (mostly where we get our fiber from). We also found shortly after that he is also intolerant to dairy. Going dairy free is tricky because you have to get rid of it even as an ingredient in other foods. He has now been on a gluten free/dairy free diet for the past few years and now is completely better. Ask your doctor to run a Celiac panel to rule it out. A lot of doctors still do not connect constipation with Celiac but it is a true symptom. Unfortunately though, the testing is not always accurate on children under 5 so you could get a false negative. Another option is to try a Gluten Free diet challenge and see if it helps. It cannot hurt her. Just google "gluten free diet" and you will get a better understanding.
Poor baby and you. I know the pain of seeing your child hurting and feeling helpless. It may be the formula that she is drinking. My best advise is to find a better Dr.! Good luck! Does she dring apple and plum juce? Try it...