Silico-mycobacterial disease in sandblasters.

Twenty-two of 83 silicotic sandblasters in the New Orleans area had complicating mycobacterial infections: 10 with Mycobacterium tuberculosis, 9 with M. kansasii, and 3 with M. intracellulare. The place of residence was related to the variety of atypical infection. The mean age of the patients was 44 years and the average exposure to silica was less than 10 years. Sputum conversion occurred in all 18 patients with positive cultures, but 8 died in respiratory failure secondary to progressive silicosis. The roentgenographic features of the disease were often atypical: Lower lobe involvement occurred in 6 patients, hilar adenopathy without calcification in 8, and diffuse filling of air spaces in 5. Pulmonary function studies usually showed a mixed pattern of obstruction and restriction associated with impaired gas transfer. Pulmonary function often declined over relatively short intervals of time with corresponding adverse chest roentgenographic alterations.