Any help...I'm at a loss

My 2 year old daughter has been sick since the end of July of 2012. We recently have been seeing an infectious disease doctor. Blood work has been performed nothing really raised any questions. Recently she's been having fevers spiking to 106 degrees. We took her to the ER and her sed rate was slightly elevated. She continued with fevers complaining of headaches, and just not feeling and just not feeling well. She also has complained of wrist pain and that her stomach hurts. Her SED raise is now quite elevated at 80-85. She has been running a slight fever since July staying around 99 . and going up to 101. We are scheduled for a pet ct scan next week. I'm at a loss. Ant insight would be much appreciated. Truly, Jennifer