NCLEX Review Guide: Severe Acute Respiratory Syndrome (SARS)

SARS Coronavirus

• SARS is caused by a coronavirus (SARS-CoV) that primarily attacks the respiratory system, leading to severe pneumonia and respiratory distress. The virus binds to ACE2 receptors in the lungs, causing direct cellular damage and triggering an excessive inflammatory response.
• Transmission occurs primarily through respiratory droplets and close person-to-person contact, with potential airborne transmission in certain settings. The virus can remain viable on surfaces for several hours to days, making fomite transmission possible.

Pathological Changes

• SARS causes diffuse alveolar damage characterized by hyaline membrane formation, interstitial inflammation, and desquamation of pneumocytes. As the disease progresses, pulmonary fibrosis may develop, leading to permanent lung damage and reduced gas exchange.
• The virus triggers a cytokine storm, an excessive immune response that damages lung tissue and can lead to multi-organ failure. Elevated levels of IL-6, IL-8, and TNF-α contribute to the inflammatory cascade.

Initial Symptoms

• SARS typically begins with flu-like symptoms including high fever (>38°C/100.4°F), malaise, myalgia, headache, and rigors. Unlike many respiratory infections, rhinorrhea (runny nose) and sore throat are less common initial symptoms.
• After 2-7 days, lower respiratory symptoms develop, including a dry, nonproductive cough and progressive dyspnea. Patients may initially appear to improve before developing more severe respiratory symptoms.

Disease Progression

• Approximately 20-30% of patients develop severe disease requiring intensive care, with respiratory failure being the primary complication. Progression to ARDS typically occurs during the second week of illness and is characterized by severe hypoxemia and bilateral pulmonary infiltrates.
• Extrapulmonary manifestations may include diarrhea (20-25% of patients), liver function abnormalities, lymphopenia, and thrombocytopenia. Older adults and those with comorbidities have a significantly higher risk of severe disease and mortality.

Diagnostic Criteria

• SARS diagnosis requires a combination of clinical, epidemiological, and laboratory criteria. Suspected cases include patients with fever, respiratory symptoms, and relevant exposure history (travel to affected areas or contact with SARS patients).
• Definitive diagnosis requires laboratory confirmation through RT-PCR testing of respiratory specimens, blood, or stool samples. Serological testing for SARS-CoV antibodies can confirm past infection but is not useful for early diagnosis.

Imaging and Laboratory Findings

• Chest radiographs typically show focal interstitial infiltrates that progress to diffuse bilateral consolidation. CT scans may reveal ground-glass opacities and focal consolidations, predominantly in peripheral and lower lung zones.
• Common laboratory abnormalities include lymphopenia (decreased lymphocyte count), elevated lactate dehydrogenase (LDH), elevated creatine kinase (CK), and thrombocytopenia. Elevated liver enzymes (ALT/AST) are seen in 20-30% of patients.

Supportive Care

• The cornerstone of SARS management is supportive care, focusing on respiratory support and prevention of complications. Oxygen therapy should be initiated for patients with hypoxemia (SpO₂ <90%), with progression to mechanical ventilation if respiratory failure develops.
• Lung-protective ventilation strategies (low tidal volumes of 4-6 mL/kg ideal body weight, plateau pressures <30 cm H₂O) are recommended for intubated patients to prevent ventilator-induced lung injury. Prone positioning may improve oxygenation in severe cases.

Procedure: Oxygen Therapy Escalation

1. Begin with nasal cannula or simple face mask if SpO₂ <90% on room air
2. Progress to high-flow nasal cannula or non-rebreather mask if inadequate response
3. Consider non-invasive ventilation (CPAP/BiPAP) with caution due to aerosolization risk
4. Prepare for early intubation if rapid deterioration or persistent hypoxemia despite non-invasive measures
5. Implement lung-protective ventilation strategies post-intubation

Pharmacological Interventions

• No specific antiviral therapy has proven consistently effective for SARS. Various agents including ribavirin, lopinavir/ritonavir, and interferon were used during the 2003 outbreak with inconclusive results. Research continues on potential antiviral therapies targeting coronavirus replication.
• Corticosteroids were widely used during the SARS outbreak to reduce inflammation, but their use remains controversial due to potential delayed viral clearance and secondary infections. If used, they should be reserved for severe cases with careful monitoring for adverse effects.

Isolation Precautions

• SARS requires strict airborne, droplet, and contact precautions. Patients should be placed in negative pressure isolation rooms with at least 12 air changes per hour. Access to patient rooms should be limited to essential personnel.
• Healthcare workers must use appropriate personal protective equipment (PPE) including N95 respirators or higher-level respirators, eye protection, gowns, and gloves. Proper donning and doffing procedures are critical to prevent self-contamination.

Nursing Assessment and Interventions

• Frequent respiratory assessment is essential, including respiratory rate, work of breathing, oxygen saturation, and auscultation when possible. Early recognition of deterioration allows for timely intervention to prevent respiratory failure.
• Nursing care should focus on maintaining adequate oxygenation, preventing complications of immobility, managing fever, ensuring adequate nutrition and hydration, and providing psychological support. Cluster care activities to minimize exposure time and PPE usage.

Surveillance and Containment

• Early identification and isolation of suspected cases is critical for containing SARS outbreaks. Surveillance systems should monitor for clusters of atypical pneumonia, particularly in healthcare settings where nosocomial transmission is common.
• Contact tracing involves identifying, assessing, and monitoring individuals who have been exposed to SARS cases. Contacts should be quarantined for 14 days from last exposure and monitored for fever and respiratory symptoms.

Prevention Strategies

• Community prevention measures include mask-wearing in public, hand hygiene, social distancing, and avoiding crowded indoor spaces. Travel restrictions and quarantine of travelers from affected areas may be implemented during outbreaks.
• Healthcare facility preparedness includes establishing protocols for early recognition and isolation of suspected cases, ensuring adequate supplies of PPE, training staff on infection control procedures, and implementing visitor restrictions during outbreaks.

• Etiology: SARS is caused by SARS-CoV, a coronavirus that primarily attacks the respiratory system, with transmission occurring through respiratory droplets and close contact.
• Clinical Presentation: Begins with fever and flu-like symptoms, progressing to dry cough and dyspnea; may follow a biphasic pattern with initial improvement followed by deterioration.
• Diagnosis: Combination of clinical presentation, exposure history, and laboratory confirmation (RT-PCR); characteristic findings include lymphopenia and bilateral infiltrates on chest imaging.
• Management: Primarily supportive care with respiratory support; no proven specific antiviral therapy; strict infection control measures essential.
• Nursing Priorities: Respiratory monitoring, oxygen administration, prevention of complications, and strict adherence to infection control protocols.
• Public Health: Early identification, isolation, contact tracing, and quarantine are critical for containment.