The primary care differential diagnosis of inhalational anthrax.
OBJECTIVE
Inhalational anthrax is an extremely rare infectious disease with nonspecific initial symptoms, thus making diagnosis on clinical grounds difficult. After a covert release of anthrax spores, primary care physicians will be among the first to evaluate cases. This study defines the primary care differential diagnosis of inhalational anthrax.


METHODS
In May 2002, we mailed survey instruments consisting of 3 randomly chosen case vignettes describing patients with inhalational anthrax to a nationwide random sample of 665 family physicians. Nonrespondents received additional mailings. Physicians were asked to provide their most likely nonanthrax diagnosis for each case.


RESULTS
The response rate was 36.9%. Diagnoses for inhalational anthrax were grouped into 35 diagnostic categories, with pneumonia (42%), influenza (10%), viral syndrome (9%), septicemia (8%), bronchitis (7%), central nervous system infection (6%), and gastroenteritis (4%) accounting for 86% of all diagnoses. Diagnoses differed significantly between cases that proved to be fatal and those that proved to be nonfatal.


CONCLUSIONS
Inhalational anthrax resembles common diagnoses in primary care. Surveillance systems for early detection of bioterrorism events that rely only on diagnostic codes will be hampered by false-positive alerts. Consequently, educating frontline physicians to recognize and respond to bioterrorism is of the highest priority.
Temte
Jonathan L
JL
Department of Family Medicine, University of Wisconsin Medical School, Madison, Wis 53715, USA. jtemte@wingra.fammed.wisc.edu
Zinkel
Andrew R
AR
D000881:Anthrax / Q000175:diagnosis*; D023482:Bioterrorism; D002983:Clinical Competence; D003937:Diagnosis, Differential; D005194:Family Practice; D005260:Female; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D012141:Respiratory Tract Infections / Q000175:diagnosis*; D014922:Wisconsin