Well, it can be done globally, but after that you will have to rewrite all those keywords like PRICE_CLOSE that use underscores.
And, something else that, at least, has happened to me: in MetaEditor, the utility 'Find and Replace' does not work well, it sometimes replaces words that don't match with the search.
Better use Notepad++, you can do this with regular expressions.
After that, when you try to compile, if you have overwritten keywords that souldn't have being replaced, then rename them with the real name.
At least, that's the best method I have found so far
Nothing is impossible. Only easy or difficult.