Bronchiolitis obliterans in an animal feed worker.

A nonsmoking animal feed worker developed severe irreversible airflow obstruction during a 2-year occupational exposure to organic matter, microorganisms, proteolytic enzymes, and both amorphous and synthetic silicates. Her pulmonary dysfunction failed to improve despite removal from the workplace and treatment with bronchodilators and corticosteroids. Open lung biopsy demonstrated peribronchiolar inflammation, scarring within the small airways, and neolumen formation, findings consistent with bronchiolitis obliterans. Energy dispersive analysis of both the bronchoalveolar lavage fluid as well as the biopsy specimens revealed the presence of silicate particles, suggesting a potential link between the silica exposure and the pathologic findings. This case suggests bronchiolitis obliterans can occur as a consequence of occupational exposure in the animal feed industry. In addition, this entity should henceforth be considered when evaluating symptomatic patients with exposure to amorphous and synthetic silicates.