The Legal Profession blog is reporting today (here) on a recent case in which an attorney was disbarred for, among other things, beating up a "defenseless client" with a baseball bat causing severe injuries. The court agreed with the Hearing Panel that "causing such injuries to his client constituted a violation of Mr. Robinson’s duty to his client." The opinion is available here.
So, just to be clear, you have a fiduciary duty to not beat up your client with a baseball bat!
All kidding aside, I wonder what the client did that made the lawyer lose it to the point of wanting to beat him up with the bat. According to this article, the attorney claimed that the client broke into the lawyer's home but those charges were dismissed.
Now, let's assume that a client breaks into a lawyer's home and threatens the lawyer or the lawyer's family. Should the lawyer be disciplined for taking action to defend his life or his family? I guess it is all a matter of degree. Just a few days ago there were reports of a recent case from a jurisdiction that recognizes the right of a homeowner to use deadly force to defend his home. See here and here.