Lessons in clinical reasoning - pitfalls, myths, and pearls: a case of chest pain and shortness of breath.

Background Defects in human cognition commonly result in clinical reasoning failures that can lead to diagnostic errors. A metacognitive structured reflection on what clinical findings fit and/or do not fit with likely and "can't miss" diagnoses may reduce such errors. Case presentation A 57-year-old man was sent to the emergency department from clinic with chest pain, severe shortness of breath, weakness, and cold sweats. Further investigation revealed multiple risk factors for coronary artery disease, sudden onset of exertional dyspnea, and chest pain that incompletely resolved with rest, mild tachycardia and hypoxia, an abnormal electrocardiogram (ECG), elevated serum cardiac biomarkers, and elevated B-type natriuretic peptide (BNP) in the absence of left-sided heart failure. He was treated for acute coronary syndrome (ACS), discharged, and quickly returned with worsening symptoms that eventually led to a diagnosis of submassive pulmonary embolism (PE). Conclusions Through integrated commentary on the diagnostic reasoning process from clinical reasoning experts at two institutions, this case underscores the importance of frequent assessment of fit along with explicit explanation of dissonant features in order to avoid premature closure and diagnostic error. A fishbone diagram is provided to visually demonstrate the major factors that contributed to the diagnostic error. A case discussant describes the importance of diagnostic schema as an analytic reasoning strategy to assist in the creation of a differential diagnosis, problem representation to summarize updated findings, a Popperian analytic approach of attempting to falsify less-likely hypotheses, and matching pertinent positives and negatives to previously learned illness scripts. Finally, this case provides clinical teaching points in addition to a pitfall, myth, and pearl specific to premature closure.