It seems like vascular irritation, inflammation, and clots explain most if not all side effects. Every pound of us has about 25 miles of pipe to be irritated. Worst effects are bound to be the lungs but there isn't a good place to have a vascular breakdown. The strokes are a sign that the irritating agent passed the blood-brain barrier that protects us from many things: this ought to have people screaming. However, I was thinking of falls and slow bleeds, something that can definitely happen to children, and maybe the child keeps quiet about it because he was doing something he shouldn't.