Severe Acute Respiratory Syndrome (SARS)
Everything about the causes, symptoms, and diagnostic methods for this type of respiratory system inflammation.
Symptoms and Causes
Severe acute respiratory syndrome (SARS) is a respiratory system infection of unknown origin that presents with symptoms similar to severe influenza or pneumonia.
SARS is a contagious disease transmitted from person to person, and in most cases, it resolves spontaneously within 6–7 days without significant worsening. However, in patients over 60 years of age or with comorbidities, it may lead to serious complications and death (occurring in approximately 3–4% of patients).
Symptoms
The most prominent symptoms of severe acute respiratory syndrome include:
- Fever above 38°C (100.4°F).
- Mild respiratory symptoms: nasal congestion, sore throat, sneezing, dry cough.
- Chills.
- Headache.
- General malaise.
- Shortness of breath.
- In severe cases, pneumonia: a lung infection that usually causes alveolar inflammation.
Causes
SARS is caused by infection with a coronavirus strain, which is also responsible for the common cold. Transmission occurs from person to person via small droplets expelled when speaking, breathing, sneezing, or coughing. Infection may also occur by touching objects or surfaces contaminated by an infected individual.
The virus causing severe acute respiratory syndrome is characterized by its spherical shape covered with spike-like proteins, giving it a crown-like appearance, which is the origin of its name. There are two types:
- SARS-CoV-1: identified in 2002 in China. It is believed to have been transmitted to humans from bats via an intermediate host. It caused an epidemiological outbreak that was controlled by 2003. No cases have been reported since 2004. Transmission occurs during the symptomatic phase.
- SARS-CoV-2 (associated with COVID-19): genetically very similar to SARS-CoV-1, but transmits more easily, including during the asymptomatic phase. Its ability to fuse with a wide variety of host cells reduces its effectiveness in some contexts.
Risk Factors
The likelihood of contracting SARS increases with direct contact with an infected person or travel to an area with higher incidence or an ongoing epidemic. The highest-risk countries include China, Taiwan, Vietnam, Singapore, and the Philippines.
SARS-CoV-2 is more frequent and presents more severe symptoms in patients with any of the following conditions:
- Hypertension
- Heart disease
- Diabetes
- Chronic obstructive pulmonary disease (COPD)
- Kidney disease
- Hepatitis
- Cancer
- Immunocompromised status
- Alzheimer’s disease
- Obesity
- Smoking
Complications
SARS complications usually occur in individuals over 60 years old with the diseases listed above. The most common complications are:
- Respiratory failure
- Heart failure
- Liver failure
Prevention
Currently, preventing SARS infection is challenging, although risk decreases with strict hygiene when living with an infected person. Recommended measures include:
- Frequent handwashing with soap and water.
- Disinfecting objects and surfaces that have been in contact with the patient.
- Wearing gloves and a mask when in the same room as the infected person.
- Ensuring proper ventilation of the room where the infected person is located (allowing exchange of indoor and outdoor air).
Which Specialist Treats SARS?
Severe acute respiratory syndrome is diagnosed and managed by pulmonology specialists.
Diagnosis
The standard procedures to diagnose SARS are:
- Medical history: review of the patient’s medical background, current health status, symptoms, and possible contact with infected individuals or travel to high-risk countries.
- Chest X-ray: X-rays are used to obtain images of the lungs. Findings compatible with pneumonia help confirm SARS diagnosis. Typical findings include:
- Opacity in one or both lungs (areas of increased density).
- Fluid-filled tissue regions.
- Inflamed areas.
- Computed tomography (CT): X-rays from multiple angles create detailed 3D images of the lungs. CT detects abnormalities not visible on standard X-rays, particularly ground-glass opacities indicating increased lung tissue density due to inflammation.
- PCR (polymerase chain reaction): detects viral genetic material in saliva, mucus, or blood samples.
Treatment
There is no specific treatment for SARS, highlighting the importance of prevention. As a viral infection, most patients (approximately 85–90%) improve spontaneously about one week after symptom onset.
Symptoms can be alleviated with the following treatments:
- Antivirals: indicated for patients at high risk of progression to severe disease.
- Oxygen therapy: administered to maintain adequate blood oxygen levels.
- Mechanical ventilation: in severe cases, a tube is inserted into the trachea to allow a machine to assist breathing.
- Corticosteroids: reduce inflammation.
- Antipyretics: lower high fever or relieve significant discomfort.
- Analgesics: relieve pain.
