Coronavirus SARS-CoV1 infection (SARS)

Essential Evidence

Last Updated on 2021-03-10 © 2021 John Wiley & Sons, Inc.

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Authors:
M. Joyce Green, MD, Assistant Professor, Penn State Health Hershey Medical Center
Pete Yunyongying, MD, FACP, Associate Professor , Carle-Illinois College of Medicine, University of Illinois
Mark H. Ebell, MD, MS, Professor, College of Public Health, University of Georgia
Mindy A. Smith, MD, MS, Clinical Professor, Department of Family Medicine, Michigan State University

Editor:
Mark H. Ebell, MD, MS, Professor, College of Public Health, University of Georgia

Overall Bottom Line

  • The most common presenting symptoms of the SARS-CoV1 in 2003 were fever, chills, myalgia, malaise, and cough. 1 Test patients for SARS-CoV1 using PCR only if no other cause of pneumonia can be found 72 hours after starting a workup and if the patient has risk factors for SARS-CoV1. Consult public health authorities prior to testing. G5C
  • Supportive care is the mainstay of treatment. Although most patients were treated with corticosteroids and antivirals, there is little evidence that these interventions improved outcomes, and they are known to have ill effects. C 2
  • The case fatality ratio in over 8000 cases reported by the WHO in 2003 was 9.6%. G18C
  • A separate chapter address infection with SARS-CoV2 and COVID-19.

Diagnosis

Bottom Line

  • Suspect severe coronavirus infection in persons with fever, cough, and other respiratory symptoms during an outbreak or pandemic.C
  • RT-PCR of multiple specimens is the most appropriate diagnostic testing method. Testing should be carried out according to guidelines from and in consultation with public health authorities. 8B

Differential Diagnosis

Diagnosis
Community-acquired pneumonia caused by strep, influenza, legionella, mycoplasma, or other viruses
COPD exacerbation
Acute pulmonary edema
Interstitial lung disease
Severe coronavirus infection due to SARS-CoV2
Hantavirus pulmonary syndrome
Opportunistic infections causing pneumonia-complicating HIV infection (pneumocystis carrnii, histoplasmosis, or disseminated varicella pneumonia)
Middle Eastern Respiratory Syndrome

Diagnostic Criteria

  • The Centers for Disease Control and Prevention provided criteria for diagnosis of SARS-CoV1. Epidemiologic criteria are based on close contacts of those with respiratory illness or confirmed cases of SARS-CoV1 or travel to an area with recent SARS-CoV1 coronavirus outbreak. G2
  • Laboratory diagnosis of SARS-CoV1 requires a positive RT-PCR (with confirmation in a second laboratory) of two specimens from different sources or collected from the same source on different days. G2
  • SARS-CoV1 can be classified as having the following stages: Early illness—presence of two or more of fever, chills, rigors, myalgia, headache, diarrhea, sore throat, or rhinorrhea. Mild to moderate respiratory illness (“respiratory phase”)—temperature of >38ºC and one or more clinical features (cough, shortness of breath, etc.) of lower respiratory illness. Severe illness—meets the criteria above and has one or more of the following: radiographic evidence of pneumonia, ARDS, or ARDS or pneumonia at autopsy with no cause.
  • In the most recent 2020 SARS-CoV2 pandemic, the WHO defines different clinical syndromes that includes: mild illness, non severe pneumonia, severe pneumonia, acute respiratory distress syndrome, sepsis. (see SARS CoV2 article).

Using the History and Physical

  • Consider SARS-CoV1 in the differential diagnosis of patients who provide a history consistent with possible exposure to the SARS-CoV1 virus, such as travel to an affected area, employment in a risky occupation, or being part of a cluster of unexplained cases of pneumonia. G4
  • The incubation period of SARS-CoV1 is typically from 2 to 14 days, with some cases described as having incubation periods as long as 21 days. 7
  • The disease begins with typical viral symptoms such as fever (99%), cough (66%), malaise (59%), chills (52%), and myalgias (48%). This is based on data from the four largest outbreaks. 1
  • The dry cough and dyspnea usually start within 2 to 7 days of the initial symptoms. 2 Two-thirds of SARS-CoV1 patients progress to a more serious respiratory phase 8 to 12 days after the onset of symptoms. 2 1
  • The respiratory phase appears to last 1 week and recovery begins 2 to 3 weeks after the initial symptoms. 2
  • Watery diarrhea occurs in around 20% of patients, and the SARS-CoV1 virus is found in large quantities in the stool. 1
  • High viral load is correlated with organ failure and death. Viral load peaks 10 days after symptom onset. 7

Selecting Diagnostic Tests

  • First, establish the diagnosis of pneumonia using CXR or chest CT, and then if possible, rule out causes other than SARS (see Differential Diagnosis). Any testing for SARS should be performed in conjunction with public health authorities. G4
  • Conventional RT-PCR shows low detection rates in early illness, and serology can take up to 28 days to reach a sensitivity above 90%.
  • Quantitative serum RT-PCR has a 79% detection rate (sensitivity) within the first 3 days, superior to nasal or throat swab and similar to that of nasopharyngeal aspirate. 9
  • Nasopharyngeal specimens are usually negative in the first week of illness, and positive in the second. Lower respiratory specimens are more likely to be positive than upper respiratory. 13
  • Collect multiple specimens including samples from different body sites and from different times during the illness. This includes acute and convalescent (>28 days) serum, sputum, nasopharyngeal, and oropharyngeal swabs, as well as stool, which demonstrates a high viral load particularly in the second week of the disease. 1 8

Approach to the Patient

  • Airborne isolation precautions and other standard infection prevention measures should be continued.
  • In the absence of known SARS outbreak, if the patient has answered yes to one of the surveillance questions in Table 1 and is hospitalized with radiographically-confirmed pneumonia, the patient should first be evaluated for common causes of community-acquired pneumonia. This includes sending sputum for routine gram stain and culture, sending urine antigens for Legionella and pneumococcus, and testing for respiratory viral pathogens.
  • If the patient is part of a cluster of pneumonia with no explained cause or at high risk for SARS with no alternative diagnosis, the patient should be tested for SARS-CoV1 and CoV2.
  • If there is known person-to-person transmission of SARS-CoV1 in the environment, the algorithm in Figure 1 from the CDC is recommended.
  • Clinicians should utilize telehealth consultations which was widely used during the COVID 19/ SARS-CoV2 pandemic. 54