Case Presentation: A 73-year-old man who had been under quarantine for a week prior to presumed COVID-19 presented to the emergency department (ED) with worsening malaise, fever, and loss of appetite. Two weeks prior, the patient presented to his primary care provider (PCP) with fevers, dry cough, exertional dyspnea, sweats, malaise, anorexia, anosmia, and dysgeusia. He was tested for the 2019-nCOV by PCR and given an empiric course of azithromycin for presumed Coronavirus Pneumonia despite a negative test. The patient returned to his PCP with persistent malaise, worsening chills, and diaphoresis and was referred to another facility for a second COVID-19 PCR test. He was discharged without further investigations with another presumed false-negative test. On admission, he was found to be very lethargic and febrile (40 ℃), with 98% oxygen saturation on room air. Physical exam was significant for irregularly irregular pulses. EKG showed new-onset atrial fibrillation. The admitting team ascertained that two weeks prior to developing symptoms, he had traveled to Vermont, where he spends significant time outdoors and horseback riding. Laboratory studies were remarkable for thrombocytopenia, which prompted the team to obtain a peripheral smear. A repeat COVID-19 PCR test came back negative. Imaging did not show any acute cardiopulmonary issues. Subsequently, the peripheral smear revealed morulae within the leukocytes. A provisional anaplasmosis diagnosis was made, and the patient was started on doxycycline. The diagnosis was confirmed with a positive DNA PCR for Anaplasma phagocytophilum. Within 24 hours of treatment with doxycycline, the patient improved significantly, with anorexia, diaphoresis, and fever resolving. After three days, all laboratory markers, including platelet count, normalized.
Discussion: Cognitive biases may lead to diagnostic inaccuracies and are important sources of medical errors. In this report, we illustrated the pitfalls of cognitive bias during the COVID-19 pandemic. During a worldwide pandemic, physicians must safeguard against cognitive biases, particularly availability bias (referring to what comes to mind easily) and framing bias (assembling elements that support a diagnosis) during clinical decision making. Diagnostic errors are estimated to occur in the ED 5-10% of the time while its prevalence is unknown in the primary care setting. The patient was seen by multiple providers prior to admission and the thorough history elicited by the admitting team made a difference in determining the correct diagnosis through accurate history and salient laboratory findings.
Conclusions: Cognitive bias can lead to inefficient utilization of resources, mismanagement, and delays in making a suitable diagnosis. While there is no fail-safe approach, potential guiding principles to protect against cognitive bias and diagnostic errors during the COVID-19 pandemic include ensuring a broad differential diagnosis beyond COVID-19, eliciting a thorough history, taking a diagnostic time out, and involving specialists.