Manganese Pneumonitis

Abstract

In the years 1938-1945 men engaged in the manufacture of KMnO4 suffered pneumonia to the extent of 63, 50,15, 30, 24, 20, 0, and 26/1000/consecutive yr. Comparable incidence of pneumonia in Boots Health Insurance Society was 0.52, 0.47, 0.91, 0.59, 0.89, 1.2, 1.0 and 0.02. Animal expts. were conducted to elucidate these observations. Mice were exposed to dust containing 70-74% MnO2 with an alkalinity calculated as KOH, varying from 9.6-0.8%. In spite of severe general toxic effects, there was no increased susceptibility to pneumococci type II or hemolytic streptococci ad- ministered intraperit., or to pneumococci group IV given in-traperit. or by means of inhalation. Depending upon the time of exposure, the lungs of mice killed or that died following such exposure showed extensive areas of consolidation especially around the bronchi. These expts. suggest that Mn has a specific action upon the lung of the mouse and that bacterial infection plays no part in producing consolidation.[long dash]Further investigations are needed to determine whether the illness in the human subjects is due entirely to chemical irritation or whether this lays open the way to bacterial infection. The term "Mn pneumonia" attaches too much significance to anatomical considerations, and "Mn pneumonitis" is better.