Actually, I'd think the first signs of abuse would be the most difficult things for a computer to diagnose. Excuses are given, nobody says anything about violence, the person slipped, but the non-verbal cues might raise a red flag.

I'm not sure how much common sense world knowledge would be in Watson. "Hey doc, I got a pain in my chest while watching the football game vs Cal at Memorial Stadium." The DDX might include angina despite the computer being unlikely to know about a fan's emotions or environment of a football game.