M.B.
Did they test her urine for a UTI? Does she have a fever? My kids have kidney issues and the pediatric urologist always tells me if there's no fever, not to worry, since it's the fever and bodies response to the UTI that does the damage/causes scarring. With pinworms you can do the tape test at home - stick some tape to anus when she's sleeping and pull off - there should be worms on it (that's what I read at least).
Good luck!