PPT Slide
Pain crises: Your blood is mostly made up of water, some chemicals (salts), and blood cells. When there is less water, the blood cells in children with sickle cell disease are more likely to change into the sickle shape (go to http://www.emory.edu/PEDS/SICKLE/rbcsickl.html to see a normally shaped cell change into a sickle shaped cell).
This leads to a lot of the problems of sickle cell disease, including pain crises. Drinking a lot of water can help prevent this from happening.