If the lung damage you are referring to is BPD, it can still show up on x-rays for a few more years. The damage is normally healed by the time they go to school though. The key would be getting someone to tell you if it is CF related lung damage or BDP related lung damage they are looking at on the x-rays - I have been told it looks similar on an x-ray. Regardless, you should get CF and Celiac totally ruled out and then keep going until you find out what her is causing her problems.