Toxic Fume Bronchiolitis Obliterans
Toxic fume bronchiolitis obliterans results from exposure to nitrogen dioxide, sulfur dioxide, and other agents that cause a spectrum of symptoms from mild nasal and throat irritation to immediate asphyxiation and death. Mild symptoms usually resolve without residual effects. The irreversible stage of bronchiolitis obliterans begins with a latent period of no respiratory symptoms for several hours after exposure followed by diffuse alveolar damage and respiratory failure four to six hours later. If recovery occurs, in one to three weeks, some patients then develop irreversible airflow obstruction due to constrictive bronchiolitis with an extensive obliterative component. This is a late lesion and lung biopsy shows irreversible scarring of the bronchioles. At this stage, the findings are identical to idiopathic bronchiolitis obliterans, early inspiratory crackles, a radiograph that is normal or shows hyperinflation and airflow obstruction.
The use of potentially toxic chemicals in manufacturing processes is increasing through out the world resulting in an increased possibility of exposed workers developing bronchiolar disorders. For example, two workers in a lithium battery factory were accidentally exposed to thionyl-cholride, and one of them developed a prolonged clinical course and findings consistent with bronchiolitis obliterans (41). This acidic compound is used in the manufacturing process and produces SO2 and HCL fumes when in contact with water.
A 1992 study of 20 patients with silo filler's disease in New York (42) confirmed that the irreversible constrictive bronchiolitis lesion is rare; however, the mortality from the acute process remains high, 20 percent died within the first 24 hours from acute alveolar injury and massive pulmonary edema. Among these 20 patients, exposures occurred during September and October, and corn silage was the exposure source in 90 percent. All were young men with an average age of 32 years. Dyspnea was the most common symptom; two of the 16 survivors had persistent respiratory complaints. One patient presented with delayed onset bronchiolitis. This patient became ill in November with five days of fever and progressive dyspnea and a chest radiograph that showed bilateral small nodular opacities. Six weeks previously, he had entered a silo the day after it was filled with corn silage. After three or four breaths, he was nearly overcome, climbed out of the silo and had moderate shortness of breath for several days. He was treated successfully with corticosteroid therapy and had no residual radiographic or clinical effects.
A possible occurrence of bronchiolitis obliterans was described in a 39 year-old truck driver who delivered fly ash and developed acute respiratory failure requiring hospitalization (43). The chest radiograph showed bilateral infiltrates, and this episode rapidly improved with corticosteroid therapy. After two weeks, he returned with significant dyspnea. The vital capacity was normal at 5.44 liters (102% predicted), but the FEV1 was decreased to 2.13 liters (52% predicted) and the FEV1/FVC ratio was severely decreased to 39 percent. It was not known whether the direct effect of the fly ash particles, or whether toxic agents such as nitrogen dioxide or sulfur dioxide adsorbed to the fly ash particle caused the injury.
Smoke inhalation bronchiolitis obliterans was described in a 23 year-old man who was in a fire while sleeping in his newly constructed house (44). He was unconscious when rescued. He had black sputum production containing soot. There was cough and mild dyspnea after recovery; however, he returned three years later because of persistent dyspnea. He had finger clubbing, an FEV1 of 0.90 liters, and an FEV1/FVC of 34 percent. Transbronchial biopsy showed chronic inflammatory changes in the bronchioles. The synthetic structural materials utilized to build his house produced gases that contained acrolain, formaldehyde, acetaldehyde, NO2, and SO2 when burned. ....................................END....................
The name itself means the destruction of the bronchioles; quite a serious condition but a very low-incidence presentation.
This part from above shows how much air the patient could suck in and little he could blow back out:
After two weeks, he returned with significant dyspnea. The vital capacity was normal at 5.44 liters (102% predicted), but the FEV1 was decreased to 2.13 liters (52% predicted)
This what makes this type of lung disease so serious even when not fatal. Needs further study.