One of my cf boys has recently started coughing up small amounts of blood every time he gets an infection. Its stops once the infection has cleared. The Dr says its nothing to worry about unless it was alot of blood. But he didnt say what actually causes the bleeding either. Sorry if I sound stupid but this hasnt happend to either of my boys in the past. His pfts are quite low at 40, and he is loosing weight. Has anybody got any input! Thanks