RESUMEN
Since the global outbreak of severe acute respiratory syndrome (SARS) in 2003, China has gradually built a robust prevention and control system for sudden infectious diseases. All large hospitals have a fever clinic that isolates patients with all kinds of acute communicable diseases as the first line of medical defense. The emergency department, as the second line of medical defense in hospitals, is constantly shouldering the heavy responsibility of screening communicable diseases while also treating all kinds of other non-communicable acute and critical diseases (Zhang et al., 2012; Zhu et al., 2015; Wang et al., 2017; Feng et al., 2018; Lu, 2018; Xu and Lu, 2019). An outbreak of pneumonia of unknown etiology that began in Wuhan city (China) has spread rapidly in China since December 2019 (Huang et al., 2020; WHO, 2020; Zhu et al., 2020). In February 2020, the National Health Commission of China named the disease a novel coronavirus pneumonia (NCP); then, it was formally named the coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO) on Feb. 11, 2020. The Coronavirus Study Group of the International Committee on Taxonomy of Viruses designated this causative virus as SARS coronavirus 2 (SARS-CoV-2). SARS-CoV-2 belongs to the β coronavirus genus, and its pathogenic mechanism has not been clarified, which requires further study. To better understand the clinical characteristics of COVID-19 and more effectively prevent and control this disease, we retrospectively analyzed four representative cases of COVID-19 that had recently been screened and diagnosed in our emergency department.