Severe Acute Respiratory Syndrome (SARS)

Key Features

• Travel to endemic area within 10 days before symptom onset, including mainland China, Hong Kong, Singapore, Taiwan, Vietnam, and Toronto

• Persistent fever, dry cough, dyspnea in most cases

• Mortality: as high as 14% in clinically diagnosed cases

Clinical Findings

• SARS is an atypical pneumonia that affects all age groups

• Incubation period is 2–7 days; it can be spread to contacts of affected patients for 10 days. Mean time from onset of clinical symptoms to hospital admission is 3–5 days

• In all clinical cases, persistent fever is present; chills/rigor, cough, shortness of breath, rales, and rhonchi are the rule

• Headache, myalgias, and sore throat are common

• Watery diarrhea occurs in subset of patients

• Elderly patients may report malaise and delirium, without fever

Diagnosis

• Serologic tests are available, but seroconversion may not occur until 3 weeks after the onset of symptoms

• Conventional reverse transcriptase polymerase chain reaction (RT-PCR)

  • Detection rates for the virus are generally low in the first week of illness

  • Urine, nasopharyngeal aspirate, and stool specimens are positive in 42%, 68%, and 97%, respectively, on day 14 of illness

• Leukopenia (particularly lymphopenia) and low-grade disseminated intravascular coagulation are common

• Modest elevations of alanine aminotransferase (ALT) and creatine kinase are frequently seen

• Arterial oxygen saturation < 95% with associated nonspecific pulmonary infiltrates is evident in 80% of affected individuals

• A high-resolution CT scan is abnormal in 67% of patients with initially normal chest radiographs

Treatment

• No specific treatment

• Supportive therapy is mainstay

• The following agents were used during the 2003 epidemic, but their efficacy remains inconclusive

  • Ribavirin (400–600 mg/day and 4 g/day)

  • Lopinavir/ritonavir (400 mg/100 mg)

  • Interferon type I

  • IVIG

  • Systemic corticosteroids