Abstract
A 50 year-old engineer developed acute respiratory failure, during exposure to nitrous fumes (NO2) and hydrogen fluoride in a stainless steel tank. His chest roentgenogram revealed marked infiltrates suggesting pulmonary edema.
A few days later, he was admitted to our hospital and his symptoms began to improve without any medication, including steroids. Microscopic examination of lung specimens obtained by TBLB demonstrated respiratory bronchiolitis with cellular infiltration and fibrous exudate. His pulmonary function studies showed only mild obstructive ventilatory disturbance and slight hypoxemia, but no impaired diffusion capacity. A study of bronchoalveolar lavage fluids (BALF) showed an increase in number of cells, almost all of which were macrophages. About 80% of these alveolar macrophages were large in size with cytoplasmic vacuoles.
One year after exposure, he remained symptomless and lung function studies and chest roentgenogram showed no abnormalities. BALF findings were normal except for Leu7-positive cells, which represented natural killer (NK) cells. The relationship between Leu7-positive cells in BALF and the activity of pulmonary diseases, however, is still to be resolved. In chemical pneumonitis, it is important to prevent the progression to bronchiolitis fibrosa obliterans. It is speculated that an autoimmune type of response might be involved in this stage. There were significant changes in the alveolar macrophages in this patient, so they might play some role in this stage of the illness.
