Hard Metal Lung Disease: Update in Diagnosis and Management

Hard metal lung disease is a rare entity due to cobalt and tungsten carbide exposure. This review summarizes the literature focusing on pathogenesis, clinical features, diagnosis, and management. Theories for pathogenesis include immunogenic activation, oxidant injury, and induction of hypoxia-inducible factor in macrophages. Multinucleated giant cells with bizarre cannibalistic features are the most common pathological finding; however, it is not pathognomonic. Corticosteroids remain the mainstay of treatment based on data from small studies. Hard metal lung disease exposure can lead to an occupational asthma or parenchymal lung disease, potentially leading to respiratory failure. A history of exposure and clinical findings along with appropriate radiographic and pathological findings are essential to establish a diagnosis. Treatment options include exposure cessation, corticosteroids, immunosuppressive therapies, and lung transplantation.