My three year old daughter has unexplained swelling and fluid on her right knee. Lyme test negative. WBC within normal range. X-rays normal. She has had this swelling for 7 weeks. Ortho also ruled out JRA. Both her pediatrician and ortho are stumped. They are setting up an mri at a local children's hospital. She is moody, has no appetite, night sweats, persistent low grade fever of about 99-100 degrees. She complains of being tired a lot. I am unsure if the mri is going to only scan her knee or if other areas will also be scanned. She has also had a dry cough off and on and she seems to get strangled when she is drinking (but isn't that normal for small children). What could be going on and should I ask her doctor to do any other diagnostic testing?

Keep on with the doctors, stay on top of it and make sure they don't slack off on finding what is going on (sadly, that does happen sometimes) keep at it. And if they come back and say nothing is wrong or they can't find anything, then get another opinion.