CayoKay,
What an excellent response! That is exactly how I would have handled it. Kids are smart, and they'll understand.

I think the key is how "You" think about MS. If you find it scary, frightening, horrible,blah, blah, blah, that will carry over and worry your child.

But if you take it all in stride, then it will be easier for her.

Having said that, excruciating pain is difficult to take in stride! So play a game of chutes and ladders, or something fun on the computer, and get rid of the jungle gym mom game!

All great suggestions. You guys are so smart!