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Severe Acute Respiratory Syndrome

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Severe Acute Respiratory Syndrome, SARS

  • See Also
  1. Middle East Respiratory Syndrome (MERS)
  • Epidemiology
  1. Asia has been epicenter of SARS outbreaks
  • Pathophysiology
  1. Coronavirus spread by respiratory droplet transmission
  • Symptoms
  1. Fever (Temperature over 100.4 F or 38 C)
  2. Chills
  3. Myalgias
  4. Non-productive Cough
  5. Headache
  6. Dizziness
  • Radiology
  1. Chest XRay (abnormal in 75% of cases at presentation)
    1. Patchy consolidation in peripheral lung fields
  2. Chest CT
    1. Peripheral "ground-glass" opacifications
  1. Lymphocyte Count >4000/uL or <1500/uL
  2. Neutrophil Count <2000/uL
  3. Platelet Count <150,000/mm3
  • Management
  1. Cover differential diagnosis
    1. Empiric treatment for Bacterial Pneumonia
  2. Non-specific measures used in SARS cases
    1. Indications
      1. Fever >48 hours
      2. Thrombocytopenia
      3. Leukopenia
    2. Management
      1. Ribavirin
      2. Methylprednisolone
  • Course
  1. Incubation Period: 2-16 days (mean 5-6 days)
  2. ICU admission rate: 23%
  3. Mechanical Ventilation required: 13.8%
  4. Mortality: 3.6%
    1. Associated with major comorbidities
  5. Time at which further hospital transmission unlikely
    1. Twenty days from last known SARS case onset
  • Prevention
  1. Respiratory protection
    1. N95 or equivalent mask
  2. SARS Vaccine
    1. WHO trials of Vaccine due to start winter of 2004
  • Risk Factors
  1. Close contact to infected patients
    1. Household contacts
    2. Healthcare workers
  2. Highest risk transmission to unmasked healthcare worker
    1. BiPap or CPAP administration
    2. Nebulizer administration
    3. Intubation
    4. Bronchoscopy
  • Prognosis
  • Predictors of worse prognosis
  1. Advanced age
  2. Lactate Dehydrogenase (LDH) increased
  3. Neutrophilia
  • References
  1. Lee (2003) N Engl J Med 348:1986-94 [PubMed]
  2. Varia (2003) CMAJ 169(4):285-92 [PubMed]