Snapshot A 43-year-old woman presents to a hospital in Singapore with a 6-day history of fever, headache, myalgias, and a 2-day history of a nonproductive cough. She recently traveled to China on business where she recalls having a sick contact while taking the train. Her temperature is 100.5°F (38.1°C). On physical exam, the patient is lethargic. Chest radiograph shows diffuse interstitial infiltrates. Tests for Legionella, Mycoplasma, and Chlamydia and immunofluorescence for influenza A and B, adenovirus, and respiratory syncytial virus were negative. Laboratory testing is significant for lymphopenia and an elevated lactate dehydrogenase. Introduction Definition a viral respiratory illness caused by SARS-associated coronavirus Epidemiology First reported in Asia ETIOLOGY Pathophysiology virus is transmitted via respiratory droplets. Presentation Symptoms prodrome (3-7 days) fever malaise headache myalgias respiratory phase nonprodutive cough dyspnea Imaging Chest radiography findings normal or diffuse interstitial infiltrates Studies Labs depressed total lymphocytes increased lactate dehydrogenase (LDH) serum antibody (typically with enzyme-linked immunosorbent assay) Treatment Treatment is typically supportive e.g., supplemented O2 and ventilation as needed there are no specific antiviral medication or steroid intervention that is found to be clinically beneficial Complications Respiratory failure Prognosis Worse prognosis higher respiratory virus titer older age underlying comorbid conditions such as diabetes and chronic hepatitis B increased lactate dehydrogenase on admission