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Key symptoms can differentiate inhalation anthrax from flu

Researchers have identified key symptoms that may help distinguish inhalation anthrax from the flu and other common respiratory conditions in the event of a bioterrorist attack, according to a new study that was funded in part by the Agency for Healthcare Research and Quality (contract 290-00-0013) as part of AHRQ's bioterrorism preparedness research portfolio.

Results of the study are being used to create the first evidence-based prehospital screening protocol designed for use in response to future anthrax attacks. By helping emergency management and public health authorities rapidly and accurately identify both potential cases and likely non-cases, this protocol—once it has been fully tested—will help to preserve scarce hospital capacity while ensuring that patients receive appropriate advanced medical care.

Combining data from the 11 cases of inhalation anthrax from the 2001 attacks with historical case reports of 17 additional patients, researchers at Weill Medical College of Cornell University compared the features of anthrax-related illness with more than 4,000 cases of common viral respiratory tract infections such as the flu. Although symptoms such as fever and cough did not reliably discriminate between anthrax and flu or flu-like illnesses, others—most notably neurologic problems like dizziness and confusion, serious gastrointestinal symptoms like nausea and vomiting, and shortness of breath—were much more common in patients with inhalation anthrax.

Although sore throat and runny nose were present in some cases of anthrax infection, these flu-like symptoms never occurred without at least one of the other symptoms, according to lead author Nathaniel Hupert, M.D., M.P.H., an assistant professor of public health and medicine at Weill Medical College of Cornell University. Four of the 11 patients who developed anthrax infection in 2001 were originally sent home with diagnoses of a viral syndrome, bronchitis, or gastroenteritis.

For more information, see "Accuracy of screening for inhalational anthrax after a bioterrorist attack," by Dr. Hupert, Gonzalo Bearman, M.D., M.P.H., Alvin I. Mushlin, M.D., Sc.M., and Mark A. Callahan, M.D., in the September 2, 2003, Annals of Internal Medicine 139(5, part 1), pp. 337-345.

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