Accuracy of Screening for Inhalational Anthrax after a Bioterrorist Attack

2 September 2003 | Volume 139 Issue 5 Part 1 | Pages 337-345

Background: Bioterrorism using anthrax claimed five lives in the United States in 2001 and remains a potential public health threat. In the aftermath of a large-scale anthrax attack, mass screening to identify early inhalational anthrax may improve both the management of individual cases and the efficiency of health resource utilization.

Purpose: To develop the evidence base for outpatient anthrax screening protocols by quantifying differences in clinical presentation between inhalational anthrax and common viral respiratory tract infections.

Design: Review, compilation, and data extraction from English-language case reports of inhalational anthrax and epidemiologic studies of influenza and other viral respiratory infections.

Data Sources: 13 reports of 28 cases of inhalational anthrax from 1920 to 2001 and 5 studies reporting on the clinical features of 2762 cases of influenza and 1932 cases of noninfluenza viral respiratory disease.

Data Synthesis: Characterization of presenting clinical symptoms in anthrax and viral disease and calculation of likelihood ratios for the presence of selected clinical features.

Results: Fever and cough do not reliably discriminate between inhalational anthrax and viral respiratory tract infection. Features suggestive of anthrax include the presence of nonheadache neurologic symptoms (positive likelihood ratio cannot be calculated), dyspnea (positive likelihood ratio, 5.3 [95% CI, 3.7 to 7.4]), nausea or vomiting (positive likelihood ratio, 5.1 [CI, 3.0 to 8.5]), and finding of any abnormality on lung auscultation (positive likelihood ratio, 8.1 [CI, 5.3 to 12.5]). In contrast, rhinorrhea (positive likelihood ratio, 0.2 [CI, 0.1 to 0.4]) and sore throat (positive likelihood ratio, 0.2 [CI, 0.1 to 0.5]) are more suggestive of viral respiratory tract infection.

Conclusion: Inhalational anthrax has characteristic clinical features that are distinct from those seen in common viral respiratory tract infections. Screening protocols based on these features may improve rapid identification of patients with presumptive inhalational anthrax in the setting of a large-scale anthrax attack.

Editors' Notes Context In the event of a bioterrorist attack, it may be difficult to distinguish inhalational anthrax from viral respiratory tract disease. Contribution This synthesis compares reported symptoms of 28 patients with inhalational anthrax and 4694 patients with viral respiratory tract illnesses. Fever and cough were common in both infections. Mental confusion or loss of consciousness, shortness of breath, and nausea and vomiting more often indicated anthrax, whereas sore throat and runny nose more often indicated viral infection. Implications Several symptoms, including neurologic and gastrointestinal symptoms and shortness of breath, may help distinguish inhalational anthrax from respiratory viral illness. –The Editors

 

Author and Article Information

From Weill Medical College of Cornell University and New York Presbyterian Hospital, New York, New York.

Acknowledgments: The authors thank Bruce R. Schackman, PhD, and R. Graham Barr, MD, MPH, for their comments on earlier drafts of this paper and the New York City Department of Health and Mental Hygiene for assistance with Chinese translation.

Grant Support: Drs. Hupert, Mushlin, and Callahan were supported by contract #290-00-0013 from the Agency for Healthcare Research and Quality and by a grant from the Fritz and Adelaide Kauffmann Foundation, New York, New York.

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Nathaniel Hupert, MD, MPH, Department of Public Health, Weill Medical College of Cornell University, 3rd Floor, 411 East 69th Street, New York, NY 10021; e-mail, nah2005{at}med.cornell.edu.

Current Author Addresses: Drs. Hupert, Mushlin, and Callahan: Department of Public Health, Weill Medical College of Cornell University, 411 East 69th Street, 3rd Floor, New York, NY 10021.

Dr. Bearman: Department of Epidemiology, Medical College of Virginia–Virginia Commonwealth University, West Hospital, Room 6-202B, 1200 East Broad Street, PO Box 980019, Richmond, VA 23298-0019.

Author Contributions: Conception and design: N. Hupert, G.M.L. Bearman, A.I. Mushlin, M.A. Callahan.

Analysis and interpretation of the data: N. Hupert, G.M.L. Bearman, A.I. Mushlin, M.A. Callahan.

Drafting of the article: N. Hupert, G.M.L. Bearman, A.I. Mushlin, M.A. Callahan.

Critical revision of the article for important intellectual content: N. Hupert, A.I. Mushlin, M.A. Callahan.

Final approval of the article: N. Hupert, G.M.L. Bearman, A.I. Mushlin, M.A. Callahan.

Statistical expertise: N. Hupert, A.I. Mushlin.

Obtaining of funding: N. Hupert, A.I. Mushlin, M.A. Callahan.

Administrative, technical, or logistic support: A.I. Mushlin, M.A. Callahan.

Collection and assembly of the data: N. Hupert, G.M.L. Bearman.