Pleural thickening in mild kaolinosis

Kaolin is found along the "fall line" in Georgia, and parenchymal changes, both simple and complicated pneumoconiosis, have been previously described. This study was done to determine whether pleural thickening occurs in workers with mild kaolin pneumoconiosis.

We evaluated 350 workers at a kaolin plant in Georgia. Thirty-two workers with abnormal chest radiographs were clinically evaluated. Twelve workers with mild kaolinosis but without any evidence of pleural changes on chest roentgenograms had computed tomography (CT) of the chest to assess the presence of pleural thickening.

Nineteen workers had radiographic changes consistent with kaolin pneumoconiosis (prevalence 5.4%), and four workers had evidence of pleural plaques (prevalence 1.1%). Five of the 12 workers had evidence of pleural thickening on CT.

This study shows that pleural thickening may be common on chest tomography in workers with kaolinosis and that the exposure to kaolin dust should be considered in the differential diagnosis of pleural thickening.