This is one of three Journal Notes this week that will discuss severe acute respiratory syndrome (SARS).

As of May 15, 2003—according to the World Health Organization (WHO)—there had been 7699 probable severe acute respiratory syndrome (SARS) cases and 598 SARS-related deaths around the world. The illness appears to have originated in the Guandong Province of China late last year; since then, major outbreaks of the disease have been reported in Vietnam, Singapore, Thailand, Canada, Taiwan, and Hong Kong.

Between March 11 to March 25, 2003, 138 patients with suspected SARS were admitted to the isolation wards of Prince of Wales Hospital in Hong Kong. In a report published in the May 15, 2003 New England Journal of Medicine , researchers analyzed the clinical, laboratory, and radiologic features of these patients, noting how many patients were admitted into intensive care and how many died. Until a diagnostic test for SARS is available, health professional’s can use this study’s results to help identify patients with SARS and determine their prognoses.

About the Study

On March 4, 2003, an initial patient who was later determined to have SARS was admitted to the Prince of Wales Hospital in Hong Kong. Between March 11, 2003 to March 25, 2003, 138 patients with suspected SARS were admitted to the isolation wards of Prince of Wales Hospital. All 138 of these patients were believed to be either secondary or tertiary cases. Secondary cases were those who contracted the illness from either direct contact with the initial patient or exposure to him in the medical ward. Tertiary cases were those who contracted the disease from secondary cases.

A diagnosis of SARS was made for the 138 study subjects based on the Centers for Disease Control and Prevention definition of SARS. The researchers diagnosed SARS in patients who met the following criteria:

  • A fever greater than 38°C (100.4°F)
  • A chest x-ray or computer tomographic (CT) scan showing evidence of an infectious process in the lung with or without cough and shortness of breath
  • History of exposure to the initial SARS patient or exposure to a secondary case patient

Physicians at the hospital conducted a number of tests on the SARS patients including:

  • Blood tests
  • Chest x-rays
  • Microbiologic tests for other known viral and bacterial causes of pneumonia

The researchers analyzed the clinical, laboratory, and radiologic data from all of the patients and recorded the number of patients who were admitted to the intensive care unit (ICU), the number of patients who died, or both.

The Findings

Of the 138 SARS cases, 112 were secondary and 26 were tertiary. The patients were 39 years old, on average. Sixty-nine of the 138 cases were health care workers. An average of six days passed between exposure to the initial SARS patient and the onset of symptoms.

The most common signs and symptoms of SARS in this group were:

  • Fever (in 100% of patients)—average body temperature of 38.4°C (101.1°F)
  • Chills and/or tremor (73.2%)
  • Muscle pain (60.9%)
  • Cough (57.3%)
  • Headache (55.8%)
  • Dizziness (42.8%)

Physicians also heard crackles through a stethoscope at the bases of patients’ lungs.

Upon further investigation, physicians also found:

  • Reduction in the number of lymphocytes (immune cells) in 69.6% of patients
  • Evidence of injury to the liver, kidneys, muscles, heart, and/or brain
  • Abnormal chest x-rays. At the onset of fever, 78.3% of patients had abnormal x-rays; this number grew to 100% of patients during the course of the disease.

23.2% of the patients were admitted to the ICU; 13.8% of patients required a respirator. By the 21st day of the outbreak, five patients had died. At the time the study was written 76 of the 138 patients (55.1%) had been discharged from the hospital. Advanced age was a good predictor of admission to the ICU and death.

How Does This Affect You?

This study highlights how quickly and easily SARS spreads from person to person. It’s highly contagious nature suggests that SARS patients must be quickly identified and isolated to contain the spread of the disease. A fast and reliable diagnostic test would make this a lot easier. Until such a test is developed, physicians need to familiarize themselves with the common signs and symptoms of SARS. An accompanying Journal Note points out how physicians could be easily deceived by SARS patients who do not present in a typical fashion. To read this Journal Note, click here .

The study also highlights the risks faced by health professionals dealing with SARS or suspected SARS cases, and the critical importance of strict safety precautions in all health care facilities that serve communities affected by this serious infection. The Canadian’s apparent success at containing their epidemic was largely due to their efforts to keep it from spreading among their health care workers before it had a chance to reach the community.