I think you may be right about that.
News reports say she collapsed from stomach flu. true or not, she still has that thyroid condition as far as I'm concerned. This URL seems to point to her having under active thyroid.
http://64.233.187.104/search?q=cache:vRC9VpxPn8gJ:www.thyroid.com/tipper.html+%22hillary+clinton%22+++thyroid&hl=en