When I was doing Sports clinic during residency, I always entered the room the same way:
First, I knocked. Then without waiting for a response, I opened the door.
Me: "Are you Mr. Jones?"
Me: "Hi, I'm Dr. Fizzy, I work with Dr. Attending." [holds out hand] "Nice to meet you."
Golly, I was polite.
Anyway, I got in this habit of shaking everyone's hands. However, when I was doing my rehab clinic, I never shook hands. Mostly because a lot of patients had strokes, brain injuries, or spinal cord injuries, and had limited hand use. Have you ever tried to offer a handshake to a high quadriplegic? It's a little awkward, to say the least. Also, a lot of patients brought in several family members and I didn't want to be shaking hands all day.
However, I remember one day in rehab clinic, I saw a patient in the afternoon who was in the room all by herself, albeit sitting in a wheelchair. So without thinking about it, I reached out to shake her hand as I introduced myself.
And she just stared at my hand.
My first instinct was to be totally embarrassed because maybe she couldn't shake my hand. But then she said, "I don't do the hand shaking thing. You've probably shaken a lot of hands today and I don't want your cold and flu germs."
Well, I never! (I did spritz myself with alcohol before entering the room.)
If you want an inkling as to whether or not your patient is crazy, the fact that she won't shake your hand is a pretty good indication. Even if she was right, it's still not a normal thing to do. She also wouldn't let me examine her, because she'd "been examined enough." Fine with me.
When I told my attending she wouldn't shake my hand, he asked me if it was because she thought I had cooties. I had to admit that it was. And she was probably right. *Achoo!*