Thoughts on the Diagnostic Process Craig

The diagnostic process is complex and incompletely understood. It is intuitive that the processes used differ in differing clinical situations. Some diagnoses are pathognomonic and are very easily made just by recognizing them for what they are. Difficult diagnoses depend on a certain unfolding and maturation over time which may take up to years or even decades to unfold. More difficult cases such as those seen in clinicopathologic conferences involve a tremendous amount of deductive reasoning and usually a key finding be it either historical, a physical finding, or a laboratory feature serve as a "pivot" to aid in narrowing an otherwise bewildering differential diagnosis. We have also studied not only the role of clinical clues in assisting the internist in making a diagnosis but the order and timing ofthe discovery of each clinical finding which may be as important as the finding itself. At the core of effective treatment is a correct diagnosis. Diagnostic acumen is what sets internists apart. Surgeons operate and obstetricians deliver babies while internists diagnose. This is our craft. As important as the diagnostic process is, it is elusive: how is it understood, how is it taught, and how is it learned? Whereas arriving at a diagnosis is largely an art form using scientific principles, there are certain fundamental types that we can recognize and, at the right teaching moment, demonstrate to our students. Distinctively, learning diagnostics is a derivative of learning medicine; it cannot be achieved quickly or easily and it takes time to develop. Herein are described several different patterns which are not meant to be clean-cut or neatly circumscribed yet may serve as examples. This classification is derived only in part from my own experiences as several internists who have eloquently described their thoughts will be cited. Although it is hard to describe the diagnostic process, one certainly recognizes it when one sees it in action. I have marveled at the diagnostic process, lines of reasoning and sheer bulk of diagnostic experience having served under Eugene Stead, A. McGehee Harvey, Philip Tumulty, C. Lockard Conley and Leighton Cluff. Although I was