A "rare pediatric disease characterized by repeated episodes of bleeding into the lungs. The many episodes of bleeding can make your child anemic. The body is able to remove most of the blood from the lungs, but a large amount of iron is often left behind. Over time, this iron, called hemosiderin, can cause permanent damage to the lungs." from http://www.madisonsfoundation.org/content/3/1/display.asp?did=534