A 67-year-old man comes to the physician because of a 6-month history of increasing shortness of breath on exertion, dry cough, and fatigue. He has not had any fevers or night sweats. He worked in a glass manufacturing factory for 15 years and retired 2 years ago. Pulmonary examination shows diffuse crackles bilaterally. An x-ray of the chest shows well-defined calcification of the rims of hilar lymph nodes and scattered nodules in both upper lung fields. Bronchoscopy with transbronchial biopsy of a calcified node is performed, and polarized microscopy shows birefringent particles surrounded by dense collagen fibers. This patient most likely has a history of exposure to which of the following substances?

Question

A 67-year-old man comes to the physician because of a 6-month history of increasing shortness of breath on exertion, dry cough, and fatigue. He has not had any fevers or night sweats. He worked in a glass manufacturing factory for 15 years and retired 2 years ago. Pulmonary examination shows diffuse crackles bilaterally. An x-ray of the chest shows well-defined calcification of the rims of hilar lymph nodes and scattered nodules in both upper lung fields. Bronchoscopy with transbronchial biopsy of a calcified node is performed, and polarized microscopy shows birefringent particles surrounded by dense collagen fibers.  This patient most likely has a history of exposure to which of the following substances?

Quizplus · Accepted Answer

Eductional Objective: Silicosis is characterized by dyspnea and productive cough occurring years after inhalational exposure to crystalline silica.  Histologically, it is characterized by birefringent silicate particles within dense, whorled collagenous nodules surrounded by dust-laden macrophages.  Radiography typically demonstrates numerous small, rounded nodules predominant in the upper lobes; calcification of the rim of hilar nodes (eggshell calcification) may also be seen.

A 67-Year-Old Man Comes to the Physician Because of a 6-Month