DrugsAlocholYou are taking care of a patient, who frequently presents to the ED for polysubstance use. You are pretty sure his altered mental status is from polysubstance use again. He was found in his home next to drug paraphernalia. He intermittently becomes severely agitated, and so you give him sedatives. He has a low-grade fever, but you attribute that to his psychomotor agitation and likely stimulant use. Because he remains confused and lethargic after 8 hours, you admit him to an inpatient team to await further metabolism of his recreational drugs and your sedation medications.

 The next day, you learn that had meningoencephalitis.

Cognitive biases are often the root cause for medical errors.

ClosedDoorSpecifically premature closure is the #1 cause of diagnostic errors. This Academic Medicine article attempts to study this concept of physician diagnostic flexibility (changing one’s mind about the patient’s diagnosis during the case presentation). Is it just a matter of teaching learners to avoid premature closure?


  • 256 primary care physicians viewed a simulated patient vignette video.

  • Physicians were divided into MORE experienced (attended medical school during 1960-1987) and LESS experienced physicians (attended medical school during 1996-2001).

  • The video is of a patient with signs and symptoms consistent with coronary heart disease (CHD). For the sake of authenticity, these patients concurrently exhibited some GI and stress-related symptoms.

  • At the mid-point of the case, the physicians were surveyed about their initial impressions of the case.

  • At the end of the case, the physicians were surveyed about their final diagnosis and disposition plans.


The results actually were expectedly quite confusing. There are multifactorial causes for diagnostic flexibility and premature closure.

Case mid-point: More experienced physicians diagnosed CHD correctly (66%) compared to less experienced physicians (55%). This is no surprise. With more experience, you may make the correct diagnosis sooner.

Physicians who were the most likely to change their minds:

  • Those with LESS experience. Specifically, if less experienced physicians selected a CHD diagnosis at the mid-point of the case, they were more likely to shift to a non-CHD diagnosis by the end of the case, compared to more experienced physicians. In this case, diagnostic flexibility was an undesired outcome. Interestingly, both less and more experienced physicians changed their diagnosis from non-CHD (mid-point) to a CHD final diagnosis with about equal frequency.
  • Those who named a non-CHD diagnosis as their mid-point impression.
  • Those who did not ask about patient’s prior cardiac disease.

So what’s the take-home point?

  1. Clinical experience is invaluable.
  2. Experience is likely more important than merely teaching learners to reason with a more analytical approach to avoid cognitive errors.

One way to teach pseudo-experience may be to present case conferences which illustrate real examples of premature closure and diagnostic flexibility.

Eva KW, Link CL, Lutfey KE, & McKinlay JB (2010). Swapping horses midstream: factors related to physicians’ changing their minds about a diagnosis. Academic medicine : journal of the Association of American Medical Colleges, 85 (7), 1112-7 PMID: 20592506


Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at https://t.co/50EapJORCa Bio: https://t.co/7v7cgJqNEn
Michelle Lin, MD