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Severe Acute Respiratory Syndrome (SARS)

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Author:    Patricia M. Pierce (ARNP, PhD, FAAN)

Purpose/Goals

The purpose of this module is to familiarize nurses and other healthcare professionals with the causes, virulence, diagnosis, and treatment of severe acute respiratory syndrome (SARS). Also included is a discussion of how individual countries must cooperate in order to prevent and/or eradicate another such viral attack. The student will be exposed to information from leading experts who understand and have researched the SARS story in order to educate healthcare professionals.

Objectives

Following completion of this module, the learner will be able to:

  1. describe the epidemiology associated with SARS,
  2. discuss the clinical features found in individuals with SARS,
  3. describe the diagnostic methods used to verify SARS,
  4. identify appropriate approaches to treatment, and
  5. identify public health measures that can control the infection.

Introduction

Within a six-month timeframe over 8,000 people worldwide became sick with severe acute respiratory syndrome (SARS). The rapid spread from continent to continent and the lethality of SARS required the combined efforts of the World Health Organization (WHO) along with many national public health agencies to isolate the cause and stem the transmission of this virus. In the meantime, over 800 people died and the economies of three areas were devastated. Media from around the world vigilantly reported the number of cases, number of deaths, and the measures used to stop transmission.

Comparisons between SARS and the 1918 influenza epidemic that killed millions have been made. The SARS virus, like the 1918 influenza virus is a recombinant human-animal strain (Maki, 2003). SARS, like influenza, may spread more during certain times of year and may be relatively dormant during other seasons; influenza typically occurs during the winter months and the SARS outbreak was worse during the spring. Just as influenza has a high mortality rate among the young, previously healthy, young healthcare workers experienced an unusually high mortality from SARS.

Observations from the Centers for Disease Control (CDC), WHO, and other leading epidemiologists concur that international travel contributed to the rapid spread of SARS from continent to continent. Although the first cases of “atypical pneumonia” appeared in November 2002 in Guandong Province in China, they were not reported and remained isolated until a physician who had treated the patients traveled to Hong Kong. He stayed in a hotel for one day before becoming ill enough to be admitted to the hospital with fever and respiratory symptoms. He became gradually worse and died 2 weeks later of respiratory failure. Two of the family members he had gone to Hong Kong to visit, 4 healthcare workers (HCWs) in the hospital, and 12 other hotel guests developed SARS. Ten of the guests were at the hotel during the physician’s stay; the others apparently became infected after exposure to those guests who had direct contact with the physician during his stay (Sampathkumar, Temesgen, Smith, Thompson, 2003). These individuals, because of international travel, exposed and infected close contacts and healthcare workers in Hanoi, Singapore, Toronto, Hong Kong and the United States.

SARS is compared to community-acquired pneumonia in that it has a high mortality rate sometimes reaching forty percent in adults older than 60; microbiologic confirmation is difficult because it is hard to culture in vitro; it is exceptionally contagious with a longer incubation period than other viruses; though it is spread by droplet, the virus survives on environmental surfaces for hours (Maki, 2003).

Fortunately, health officials throughout the world responded rapidly to limit the spread of the infection. Passengers were screened at airports, citizens wore masks to protect themselves, case finding and quarantines were implemented, and travel to infected areas was severely restricted both by travelers not wanting to be exposed and by officials who wanted to limit additional cases.

The United States reported a total of 372 cases by the beginning of June 2003. Of these, 303 were suspect cases and 69 probable cases. So far, no deaths from SARS have occurred in the United States.

Cases Defined

SARS is suspected in people who exhibit: fever > 38 C (100.4 F) and symptoms of a lower respiratory infection, 1) within ten days of traveling to a region that has documented transmission or 2) close contact with another individual believed to have SARS. These individuals are designated as suspect cases. Probable cases have all the symptoms exhibited by suspect cases plus positive chest film findings for pneumonia, an acute respiratory infection with distress, unexplained respiratory illness resulting in death and autopsy findings of an acute respiratory distress illness (Sampathkumar, et al., 2003). Both probable and suspect cases are also examined through laboratory tests to determine if the individual is positive for the SARS virus.

While SARS is transmitted easily, walking by someone with SARS or sitting in the same room will not be enough contact to transmit the disease. Close contact is required and defined as exposure to body fluids, sharing eating utensils, kissing, performing a physical examination, (Sampathkumar, et al., 2003). The CDC guidelines state: “droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons nearby” (CDC Website, 2003). Only a few cases of SARS have been identified in the pediatric population and children do not seem to become as ill as adults.

Epidemiology

The rapid spread and virulence of SARS prompted scientists and health organizations to direct significant efforts toward uncovering the cause. The discovery of a new coronavirus resulted. Identification of the causative agent was a key goal of scientists so that the disease could be accurately diagnosed, meaningful prevention efforts could be instituted, and curative treatment modalities defined.

Coronaviruses are enveloped RNA viruses that cause disease in both animals and humans. In fact, researchers detected coronaviruses genetically linked to SARS associated coronavirus (SARS-CoV) that are found in animals. Some of these animals are considered delicacies in southern China where the initial outbreak occurred. Similarly, researchers in Hong Kong theorize that the virus was spread by a rat leaving excreta, saliva, and/or urine in one apartment residence then continuing on throughout the apartment building to contaminate other residences (Ng, 2003). The leap from animal to man makes SARS-CoV particularly troubling to world health, prevention, and treatment

People with SARS have diffuse alveolar lung damage including: desquamation of pneumocytes, formation of hyaline membrane, edema and inflammatory cells (Kuiken, Fouchier, Schutten, Rinnelswann, van Amerongen, and van Riel, 2003). Within the damaged tissue, scientists were able to isolate a previous unrecognized coronavirus called SARS-CoV.

Kuiken, et al. (2003) used patients who met the WHO diagnostic criteria for SARS and collected samples from the nose, pharynx, and conjunctiva. They also used aspirates from the nasopharynx and trachea; some subjects had bronchoaveolar lavage to elicit samples. They created virus stock for injection in monkey kidney cells and laryngeal cancer cells; stock was also placed on conjunctive and nasal passages of Macaque monkeys. They developed an immunohistochemical method to detect the SARS-CoV antigen. Kuiken et al. (2003) found that 75 percent of patients who fit the WHO criteria for SARS did have the SARS-CoV virus. Twelve percent of the remainder had human metapneumovirus infections. The respiratory tract seemed to experience the most serious consequences for the SARS virus.

Researchers in Toronto report similar experience. Varia, Wilson, Sarwal, McGeer, Gournis, Galanis and Henry (2003) collected data on 128 probable and suspect cases. Included in the sample were 35 (32%) healthcare workers and hospital staff. An elderly woman who had traveled to Hong Kong was identified as the Toronto index case. This woman infected a family member who then went to the hospital for treatment; this contact resulted in the spread to healthcare and hospital workers. In Toronto, at the index hospital, 60% of the critical care unit nurses developed SARS despite the finding that nurses had only a three-hour period of unprotected exposure.

Findings about incubation periods remain consistent among researchers at 2 to 10 days. A patient is considered contagious for 10 days after symptoms have gone away (CDC website, 2003).

Clinical Features

The onset of SARS is indistinguishable from other viral infections. Most patients complain about influenza-like symptoms, i.e., fever, myalgia, headache. The fever may be high, but may be missing in some infected elderly persons. As many as 25% of patients experience diarrhea. Respiratory symptoms, usually a dry, non-productive cough, begin within two to four days of the fever’s onset. Unlike other respiratory infections, coryza and sore throat are missing form SARS patients. Progression of respiratory symptoms is often dramatic and frequently requires hospitalization. Estimates are that 10%-20% of patients require tracheal intubation and mechanical ventilation to overcome the severity of respiratory compromise (Sampathkumar, et al. 2003).

The mortality rate of SARS victims causes great concern. Approximately 45% of individuals over 60 and with co-morbid conditions such as diabetes, renal failure and other chronic illnesses died when they became infected with the SARS virus (Sampathkumar, et al. 2003). Equally disconcerting has been the number of young, healthy people, including many healthcare workers, who succumbed to SARS. Sampathkumar, et al. (2003) suggest that healthcare workers may be exposed to patients who have a higher viral load that makes those patients more contagious.

Some researchers and clinicians have identified a biphasic disease course. Many patients experience recovery from the initial illness and then, within a few days, deteriorate (CDC website, 2003; Sampathkumar, et al. 2003). In a cohort of 75 patients in Hong Kong, as many as 85% had recurrence of symptoms including new lung infiltrates, fever, myalgia, diarrhea, hypoxemia (Sampathkumar, et al. 2003). Clinicians hypothesize that the recurrence is related to the immune response of the infected person rather than renewed viral replication.

Kuiken, et al. (2003) identified that human metapneumovirus existed as a co-morbidity in many patients, especially healthcare workers. These patients usually exhibit a mild upper respiratory infection or may have severe bronchiolitis along with pneumonia. These researchers theorize that human metapneumovirus causes the exacerbations noticed in so many SARS victims.

Diagnosis

A screening algorithm has been developed to help clinicians triage patients, particularly those complaining about upper respiratory symptoms. The question, “Have you been asked about your travel history today?” begins the triage process. If not, the patient is then asked about travel to China, Hong Kong, Singapore, Taiwan, or Vietnam in the preceding two weeks and/or is asked about contact with someone who has traveled to those places and has symptoms of fever, cough, or dyspnea. If the interview is positive, the patient should be given a mask and isolated. The physician is called to further evaluate. All healthcare workers in the environment should be advised that it is necessary to wear protective personal equipment. If the patient with suspected SARS requires further testing, exposure to other patients and staff should be minimized.

The diagnosis of SARS is made through clinical recognition of prevailing symptoms, i.e., fever, myalgia, headache, diarrhea, dry-nonproductive cough and confirmed with laboratory tests. Patients who have been symptomatic for a few days may experience hypoxia because insufficient oxygen is getting into the blood.

Radiology findings show patchy infiltrates and/or consolidation often with a peripheral distribution. Many patients do not have radiographic findings during the early stages of the disease and computerized tomography (CT) may be a better diagnostic tool. Findings on CT often resemble ground-glass consolidation appearance.

Laboratory studies are also performed. The RT-PCR (reverse transcription polymerase chain reaction) test is used to detect SARS-CoV in specimens, including blood, stool and nasal secretions. Typical findings in patients with SARS are thrombocytopenia and leukopenia. Some patients have elevated creataine kinase, lactate dehydrogenase and transaminase levels. A poor prognosis is often associated with an initial high white blood count in combination with a high peak lactate dehydrogenase (Sampathkumar, et al. 2003). Blood cultures and sputum for gram stain and culture are also done. Serum specimens collected throughout the course of the disease are sent to the CDC for analysis. The CDC has developed reagents for SARS antibody testing and these are available to state health laboratories. It is interesting to note that, despite the number and proximity of specimens containing the virus, no cluster of illness outbreaks have been identified among laboratory workers. Laboratory workers always use standard precautions when handling the specimens.

Treatment

While there is no specific therapeutic regimen currently available for SARS patients, work continues to develop an immunization for prevention or specific antiviral agents to treat this condition. Care centers on supportive care measures and infection control to prevent spread. As many as 20% percent of patients require significant respiratory support, including mechanical ventilation. Family members must be advised regarding infection control procedures

Most practitioners use clinical protocols similar to those for community-acquired pneumonia when treating a suspected or probable SARS case. Broad spectrum antibiotics, including a flouroquininolone or macrolide are used. Patients in Hong Kong and Toronto were also treated with the antiviral ribavirin. Most clinicians do not recommend ribavirin because of the drug’s toxicity, including hemolytic anemia and electrolyte imbalance.

Infection Control

The key to preventing SARS is a high index of suspicion so that early recognition is accomplished. As soon as SARS is suspected, the patient should be isolated and all workers, family members, and visitors should use precautions, including masks and personal protective equipment. The CDC recommends continuing precautions for ten days after the respiratory symptoms and fever are gone (CDC website, 2003). SARS patients are to limit contact with the outside world and stay away from work, school and public areas for ten days after the symptoms have disappeared. Key among all the recommendations is frequent and careful hand washing with soap and water or an alcohol-based hand rub particularly after contact with body fluids. Gloves, in conjunction with good hand hygiene, are recommended for any direct contact.

Patients should be instructed wear a mask when in the presence of family members or visitors; they should place secretions from coughing or sneezing in tissues and then in a plastic-lined container for disposal. Patients need to realize the importance of personal hand hygiene and should be instructed how to manage body fluids and body fluid disposal.

When patients with SARS are admitted to the hospital, special precautions should be used. Sampathkumar, et al. suggested the following guidelines (2003).

  1. Place the patient in a negative pressure room with special ventilation.
  2. Maintain a log of all persons entering the room.
  3. Restrict visitors as much as possible.
  4. Limit the number of hospital personnel that have contact with the patient.
  5. Healthcare workers should use personal protective equipment, airborne precautions, and eye protection.
  6. No equipment should enter and leave the room, including pens, charts, etc.
  7. Minimize air turbulence when changing linen.
  8. Avoid use of noninvasive positive pressure ventilation (CPAP, BiPAP).
  9. Use closed-suctioning devices and HEPA filtration on exhalation valve posts for mechanically ventilated patients.
  10. Educate personnel involved in the patient’s care to be vigilant for symptoms of SARS for 10 days after contact with the patient.
  11. Quarantine personnel with unprotected contact with a SARS patient during an aerosol-generating procedure, i.e., intubation, bronchoscopy, suctioning (p. 888).

These guidelines are consistent with the recommendations from CDC. Unnecessary exposure of healthcare workers is avoided only when the entire healthcare team is vigilant. The United States did not experience the same level of healthcare worker illness as Toronto did because the first contact in the hospital had a high index of suspicion and isolated a suspected patient before personnel were unnecessarily exposed.

At the beginning of the SARS outbreak, the CDC began issuing guidelines, advisories, and alerts. An advisory recommends that nonessential travel be postponed. An alert informs travelers of potential concerns, suggests some precautions, but does not advise against travel.

The CDC has published guidelines for businesses whose employees travel between the US and areas with SARS. While these guidelines do not mandate that returning workers be quarantined, they recommend that any person returning from a SARS area should immediately seek healthcare if symptoms appear, e.g., fever, respiratory symptoms. The healthcare provider should be notified in advance to expect someone with symptoms who has traveled to a SARS area so the necessary infection control can be in place before the ill traveler arrives.

In addition to healthcare workers, personnel in the travel industry are at great risk of exposure to the SARS-CoV. Passengers traveling with people who have been exposed are also at risk. The CDC published guidelines for airline personnel who are in the passenger service cabin during flights. The recommendations focus on preventing spread and contamination by using excellent hand hygiene with soap and water or an alcohol hand-rub. Gloves are also recommended, but do not replace hand hygiene. CDC has not recommended masks because not enough is known about the effectiveness of masks over a long flight. Will the mask become contaminated and thus the wearers have a false sense of security. The flight crew must be attentive to the possibility that surfaces of objects may be contaminated and by touching those infected objects and then touching one’s eyes, nose, or mouth, could self-infect him/her. CDC does recommend the ill passenger wear a mask and use good technique when disposing of respiratory secretions.

The crew that cleans an aircraft that is returning from a SARS area is at risk for contracting the SARS-CoV. CDC has issued guidelines for the airline industry to use for airplane maintenance. They include notifying the ground crew of the contamination; providing appropriate personal protective equipment; providing appropriate cleaning and disinfecting materials; wearing gloves during the cleaning process; cleaning frequently touched items, i.e., armrests, tray table, light and air controls, lavatory surfaces, with recommended germicide; and informing cleaning crew what to do if they become symptomatic during the ten day period after cleaning the aircraft (CDC website, 2003).

Public Health Implications

SARS taught the world that cooperation is mandatory in order to identify and eliminate an infectious disease. Further, SARS underscored that global health is a national security issue for the United States and that health concerns have significant economic implications. The economic losses that Hong Kong and Toronto endured were not trivial and could happen to any economy in the face of a global health threat.

After the discovery of the viral cause to SARS by Dr. Carlo Urbani and subsequent confirmation by scientists around the world, the international scientific collaboration has been unprecedented. Centers in Singapore, Hong Kong, Canada, Germany, WHO, and CDC collaborated to establish methodologies to identify, isolate, and create prevention and containment of this virulent SARS virus. The CDC response included the following actions:

  1. activated the Emergency Operations Center for round-the-clock coordination and response,
  2. committed more than 800 experts and support staff to work on SARS,
  3. deployed specialists to conduct on-site investigations around the world,
  4. assisted state and local health departments in their investigation efforts,
  5. provided extensive laboratory testing of specimens,
  6. distributed health alerts to travelers, and
  7. continues to work with experts to plan for rapid response if resurgence occurs (CDC website, 2003).

Nurses have an opportunity to participate in the identification, treatment and elimination of global health threats. Many nurses area involved in international research and can collaborate with colleagues from other countries to: develop strategies for educating practicing nurses about global health threats, design research that collaborates with other scientists to define the cause of global health threats, identification nursing care interventions that facilitate healing, participate with other healthcare workers to improve infection control methodologies, and provide educational information to travelers and families to reduce the risk of experiencing an illness from inadvertent exposure.

Conclusion

No longer can any country sit complacently when a new viral threat emerges. The global economy necessitates that nations come together to collaborate and determine strategies for identifying the cause and treatment of a global infectious agent.

Nurses as frontline healthcare workers are pivotal in the containment of an infectious threat. Staying current with the possibility of new viral and bacterial agents must be part of nursing practice not only to prevent the spread to other individuals but also to prevent unnecessary contamination of healthcare workers.

SARS has been a lesson for all people. The future of global health concerns remains unknown. Vigilance and collaboration among countries, healthcare workers, business entities and health organizations are necessary to promote the health and safety of the world’s population.

References

Centers for Disease Control and Prevention. (2003). Fact sheet: Basic information about SARS. Retrieved September 9, 2003, from http://www.cdc.gov/ncidod/sars/factsheet.htm

Kuiden, T; Fouchier, R.A.; Schuttenm, M; Rimmelzwaan, G. F.; van Amerongen, G.; van Riel, D.; et al. (2003). Newly discovered coronavirus as the primary cause of severe acute respiratory syndrome. Lancet, 352, 263-271.

Maki, D. G. (2003). SARS: 1918 revisited? The urgent need for global collaboration in public health. Mayo Clinic Proceedings, 78, 813-816.

Ng, S. K. (2003). Possible role of an animal vector in the SARS outbreak at Amoy Gardens. Lancet, 362, 570-573.

Sampathkumar, P, Temesgen, Z., Smith, T. F., Thomsson, R. L. (2003). SARS: Epidemiology, clinical presentation, management and infection control measures. Mayo Clinic Proceedings, 78, 882-890.

Shine, D., Ross, A., (2003). The healthcare doctrine. Modern Healthcare, 33, 22-23.