During a press conference in 2002, then Secretary of Defense Donald Rumsfeld provided a categorization of information. To Rumsfeld, information could be divided into three types: known knowns, which are things that we know we know; known unknowns, which are things that we know we don’t know; and unknown unknowns, which are things that we don’t know we don’t know.
This categorization has been much discussed (as well as criticized, touted, and mocked, depending upon your point of view). While history will ultimately judge the wisdom of Rumsfeld’s policies, I am convinced that, when it comes to medicine, there is truth in his thinking. Indeed, I believe that dealing with unknowns – both known and unknown – is at the heart of medical practice and successful patient care comes from learning to make decisions in the face of the uncertain, the imprecise, and the imponderable.
To illustrate this point, I would like to describe a case. This case is a classic example of known and unknown unknowns, and I want your opinion on its management. As you will see, this case is tricky because the rheumatologist was an adviser and not the decider.