-itis

I really like the way they pluralize conditions that end with -itis. Example: when you're talking about all the different forms of vasculitis, you say "the vasculitides" (vas-cu-LID-id-ees). It is super fun to say fast. I think my favorite is hepatitis, which becomes hepatitides (hep-uh-TID-id-ees).

Those two, nephritis, and meningitis are the only -itises (-itides???) that I've really heard people do the weird pluralization for. The thing is, you only pluralize -itis to indicate that you're talking about a group of multiple distinct syndromes, not to indicate multiple occurrences of a single disease. Like, it wouldn't work to say, "There sure are a lot of rhinitides going around these days" because that makes it sound like there's a whole bunch of different causes and different rhinitic syndromes when really, everyone just has a stuffy nose and it's probably mostly from the same virus. Most other inflammatory conditions besides the ones I mentioned don't really come as groups of distinct syndromes with different causes, so there's generally no need to pluralize. And that makes me kind of sad, because I really like weird Latin pluralizations.