Occupationally related asthma, bronchitis, or respiratory hypersensitivity reaction is an inflammation of the lungs (pneumonitis) or breathing difficulty caused by inhalation of noxious chemicals.
A. Clinical Description
Acute chemical pneumonitis causes swelling of the lung tissue, movement of fluid into the air spaces in the lung, and less ability to absorb oxygen and get rid of carbon dioxide. In severe cases, death may result from lack of oxygen reaching the tissues (hypoxia). Chronic chemical pneumonitis can follow low levels of exposure to the lung irritant over extended periods. This causes inflammation and may provoke fibrosis (scarring) with decreased oxygen exchange and stiffening of the lung. Unchecked, this condition may ultimately lead to respiratory failure and death.
Symptoms of acute exposure include an unusual feeling, possibly a feeling of burning in the chest, difficulty breathing, coughing, and abnormal lung sounds. Symptoms of chronic exposure include shortness of breath with only mild exercise, rapid breatthing, cough, and progressive disability related to shortness of breath.
B. Sources of Exposure
Many household and industrial chemicals can produce both an acute and a chronic form of inflammation in the lung. Chlorine is one of the most irritating of commonly inhaled substances. Exposure to dangerous levels may occur at home (during use of cleaning materials such as chlorine bleach), in industrial accidents, or near swimming pools. Inhalation of dangerous substances can occur in many different settings, including factories (especially during smelting, welding, or other metal work), the production or use of solvents or pesticides, fires (house fires, wildfires), and the handling of grain.
C. Population at Risk
The primary population at risk are those who work with chemicals in an occupational setting.
D. Diagnosis, Treatment, and Prognosis
Diagnosis is made by taking an occupational exposure history and through a chest x-ray, lung function studies, and blood-gas analysis.
The most important treatment is to stop the exposure to the chemical that caused the symptoms. Further teatment is focused on reducing symptoms. Oygen therapy may be helpful, and corticosteroids may be given to reduce inflammation.
The outcome depends on the chemical agent involved, the severity of exposure, and whether the problem is acute or chronic. Respiratory failure and death can occur.
E. Prevention of Exposure
Work rules on breathing masks should be followed, and the appropriate breathing mask should be worn. People who work near fires should take care to limit exposure to smoke or gases.