Background and purpose: To characterize the clinical and laboratory features of severe acute respiratory syndrome (SARS) in the early stage and to compare them with those of patients initially suspected of having SARS who were later determined to have other febrile diseases.
Methods: Between March and June 2003, 122 patients with possible SARS were admitted to the isolation ward of Tri-Service General Hospital. SARS was diagnosed according to the modified World Health Organization case definition (May 1, 2003). Among them, 43 were classified as probable SARS cases and a SARS etiology was excluded in 32 patients.
Results: Presenting symptoms on admission included fever (97.7% of probable cases, 84.4% of excluded cases), chills (39.5% vs 18.8%), cough with sputum production (16.3% vs 40.6%), dry cough (23.3% vs 9.4%), dyspnea (18.6% vs 9.4%), diarrhea (14.0% vs none), rhinorrhea (2.3% vs none), and myalgia (7.0% vs 6.6%). Common laboratory features included lymphopenia and elevated aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, C-reactive protein and creatine kinase values. Intubation and mechanical ventilation were required in 12 probable cases and 6 excluded cases. Five patients with probable SARS (11.6%) died. A scoring system which was developed to differentiate SARS patients from other febrile patients in the emergency room could differentiate probable cases from excluded cases with a sensitivity of 36.4% and a specificity of 70.6%.
Conclusions: The clinical presentation and laboratory features at the early stage do not allow differentiation of patients with SARS-CoV infection from other febrile patients. Thus, it is mandatory for all healthcare workers to strictly follow standard isolation precautions during an outbreak to minimize disease transmission.