I'd like to add to the chorus of catarrh being well-known to me - even though I might have trouble spelling it, and certainly trouble seeing it in a 7-by game.
In fact, I have no problem with any of the three words Les mentioned: catarrh; cystitis; or loupe.
I'm not sure Les meant to refer to loupe as being a medical term, but it is particularly common to me.
I vote they stay common.