Wow, it's nice to know *why* this happens! In the past month my toes (what a weird thing) have been cramping up in the middle of the night. I wake up and they're freaking out and it hurts so bad! I had no idea why. So it could be potassium and/or magnesium? Hmmm.
In '95, I was actually on a field trip to Paris of all places, (an art school thing), and while I was in front of the Louvre it was like lightning struck me and out of the blue all of my joints became so achey I could hardly move. I could hardly explain it to the people around me at the time because they just thought I was a freak. I felt like I was 150 years old for almost my whole there, one week! I never had an episode like that before or again, but maybe it was because of CF. I never knew.