The most difficult part of diagnosis is deciding which of a patient’s findings are in the “foreground” (part of the diagnosis being sought) versus the “background” (not related to the current diagnosis). In a New England Journal of Medicine case discussion, Dr. Stephanie V. Sherman stressed that “In a complex case, it can be helpful to identify the features in the background, middle ground, and foreground that form the overall clinical landscape”.
This judgment depends on a variety of factors, including knowledge of pathophysiology, temporal association, and interventions that have been done. Clinicians try to keep all the findings in mind and when creating a differential diagnosis they toggle which findings should be considered in the foreground.
Example to work through
This element is illustrated with the case of a 50 year old woman with diarrhea, weight loss, abdominal distension and anemia, but no exposure to poor sanitary conditions. Initially, all findings are assumed to be in the “foreground”. One can then put a finding into the background by “pausing” it, in the software by using the standard pause symbol used for video or audio players, as shown in the image below. In this example, there is abdominal distension. With all findings in the foreground, the top two diseases in the differential diagnosis for this patient are forms of inflammatory bowel disease. (Click any of the images to launch the software with the findings and settings as shown).
If the abdominal distension might be in the “background”, you can click the pause symbol to the right of abdominal distension. The abdominal distension finding is then grayed out, its pertinence metric (green shading bar) is set to zero, and it is moved to the bottom of the list of findings, which is ranked by pertinence. The differential diagnosis then changes to rank higher the possibility of colorectal cancer, in which abdominal distension is less common.
One can restore abdominal distension to the foreground by clicking the play symbol to the right of abdominal distension.
When clinicians work together to reach a diagnosis, many findings are often not mentioned because of uncertainty as to whether they are involved in the diagnosis being sought. The availability of this Background feature encourages clinicians to include such findings and “pause” them into the background so that a colleague has the opportunity to put the finding into play to test a diagnostic hypothesis.
This page is part of a series on the Elements of Diagnosis.
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