Keith,
Just an afterthought on figuring out what "hyponatremia" means, from its Greek and Latin roots . . .
hypo- too little (opposite is hyper- = too much)
natr- sodium (the chemical symbol for sodium is Na, from the Latin "natrium")
-emia blood (cf. anemia = an- without + -emia blood)
So "hyponatremia" means "too-little-sodium blood." Similarly "hypoglycemia" means "not-enough-sugar blood," i.e., low blood sugar.
Mark Spahn
Keith Burgess-Jackson, J.D., Ph.D. 