DIAGNOSIS IN GENERAL PRACTICE Iterative diagnosis

摘要

The traditional model of diagnosis is one of initial collection of information in the history and examination, followed by deductive steps to reach a diagnosis. We suspect that most clinicians do not recognise or use this process.A more realistic model was formulated by Elstein and Schwarz 25 years ago.1 It was called the hypo-thetico-deductive model, but we will call it the process of iterative diagnosis. This model recognises that clinical reasoning usually involves the clinician generating one or more possible hypotheses early on in the consultation (often, but not always, by pattern recognition2) and then recurrently-iteratively-testing these. Clinicians use many such shortcuts (heuristics) in clinical reasoning. This is not a fault: the shortcuts are typically correct and allow them to arrive at a working diagnosis with the minimum of delay, while avoiding excessive testing and anxiety. Exhaustive data collection without hypotheses-the medical student's history and examination-usually does not improve diagnostic accuracy and may make it worse.