SARS (severe acute respiratory syndrome)

Severe acute respiratory syndrome or SARS is a respiratory disease in humans which is caused by the SARS coronavirus.
Initial symptoms are flu like and may include: fever, myalgia, lethargy, gastrointestinal symptoms, cough, sore throat and other non-specific symptoms. The only symptom that is common to all patients appears to be a fever above 38 °C (100.4 °F). Shortness of breath may occur later. Symptoms usually appear 2–10 days following exposure, but up to 13 days has been reported. In most cases symptoms appear within 2–3 days. About 10–20% of cases require mechanical ventilation.
The Chest X-ray (CXR) appearance of SARS is variable. There is no pathognomonic appearance of SARS but is commonly felt to be abnormal with patchy infiltrates in any part of the lungs. The initial CXR may be clear.
White blood cell and platelet counts are often low. Early reports indicated a tendency to relative neutrophilia and a relative lymphopenia — relative because the total number of white blood cells tends to be low. Other suggestive laboratory tests are raised lactate dehydrogenase and slightly raised creatine kinase and C-Reactive protein levels.
Diagnostic tests
With the identification and sequencing of the RNA of the coronavirus responsible for SARS on April 12, 2003, several diagnostic test kits have been produced and are now being tested for their suitability for use.
Three possible diagnostic tests have emerged, each with drawbacks. The first, an ELISA (enzyme-linked immunosorbent assay) test detects antibodies to SARS reliably but only 21 days after the onset of symptoms. The second, an immunofluorescence assay, can detect antibodies 10 days after the onset of the disease but is a labour and time intensive test, requiring an immunofluorescence microscope and an experienced operator. The last test is a PCR (polymerase chain reaction) test that can detect genetic material of the SARS virus in specimens ranging from blood, sputum, tissue samples and stools. The PCR tests so far have proven to be very specific but not very sensitive. This means that while a positive PCR test result is strongly indicative that the patient is infected with SARS, a negative test result does not mean that the patient does not have SARS.
SARS may be suspected in a patient who has:
1. Any of the symptoms including a fever of 38 °C (100.4 °F) or more AND
2.Either a history of :
1.Contact (sexual or casual) with someone with a diagnosis of SARS within the last 10 days OR Travel to any of the regions identified by the WHO as areas with recent local transmission of SARS (affected regions as of 10 May 2003[3] were parts of China, Hong Kong, Singapore and the province of Ontario, Canada
Treatment
Antibiotics are ineffective. Treatment of SARS so far has been largely supportive with antipyretics, supplemental oxygen and ventilatory support as needed. Suspected cases of SARS must be isolated, preferably in negative pressure rooms, with full barrier nursing precautions taken for any necessary contact with these patients. There was initially anecdotal support for steroids and the antiviral drug ribavirin, but no published evidence has supported this therapy. Many clinicians now suspect that ribavirin is detrimental. Researchers are currently testing all known antiviral treatments for other diseases including AIDS, hepatitis, influenza and others on the SARS-causing coronavirus. There is some evidence that some of the more serious damage in SARS is due to the body's own immune system overreacting to the virus. There may be some benefit from using steroids and other immune modulating agents in the treatment of the more acute SARS patients. Research is continuing in this area.