A 43-year-old colonel with chills, diaphoresis, and headache.

The objectives were to illustrate the ease with which one might attribute concomitant or subsequent illness to an exposure such as the anthrax vaccine and to demonstrate an approach that keeps the significance of such exposures in appropriate perspective. A 43-year-old, active duty, Army officer presents with a variety of nonspecific common symptoms and raises concerns about the relationship of his symptoms to receipt of the anthrax vaccine. He is admitted for an evaluation that includes a series of diagnostic tests and consultations. The course of his illness and the corresponding evaluation are reviewed using a series of questions and accompanying discussions to highlight key points regarding diagnostic considerations, the anthrax vaccine, and the ultimate identification of the correct diagnosis.