PRINCIPLES OF TOXICOLOGY - Biology East Borneo

184 PULMONOTOXICITY: TOXIC EFFECTS IN THE LUNGwith difficulty breathing, they are already in an advanced stage of pulmonary decline, and the conditionis difficult to treat. It is critical that individuals who have been exposed (or potentially exposed) toagents known to cause pulmonary edema, be kept overnight (or at least 24 h following the exposure)at a medical facility where they can be closely monitored. A series of chest X rays during the “ criticalperiod,” when pulmonary edema could be initiated, should be taken and examined for the appearanceof fluid in the lung.Respiratory Allergic ResponsesAmong the potential allergic reactions of the respiratory system in industrial exposures, there are manywell-characterized conditions, as well as somewhat mysterious and hard-to-define personnel histories.Many of the characterized diseases have historically involved certain occupations and are often namedafter the occupations in which they were first observed. The allergic reactions involve antibodyformation against certain inhaled toxins or to dusts and organic particles. Subsequent exposure to thesame agent then often results in a more severe reaction, which is understandably a real problem in theworkplace where individuals often work in the same environment and receive repeated exposures. Inthe less characterized occurrences, it often appears that exposure to one agent might result in anonspecific reaction to a multitude of other compounds inhaled at some later time.Occupation-Related Inhaled Allergic DisordersA very old disease, known as “farmers’ lung,” involves the allergic reaction to the Actinomycetesspores found in hay. Hay that is collected in the field is often damp, and the high temperatures that canarise inside damp hay over time may give rise to large numbers of the thermophilic Actinomycetesspores. When the farmers inhale these spores, IgG antibodies are produced (against the spores), andsubsequent exposures result in potentially severe allergic reactions. An interesting aspect of the diseaseis that the time interval between the initial exposure and the expressed toxicity can be highly variable.Various aches and pains, fever, chills, cough, weight loss, and malaise accompany the condition, whichis often confused with pneumonia. Over the long term, fibrosis can also materialize. “Malt worker’slung,” contracted from the dust of bird droppings, presents with similar allergic alveolitis and has beenreported in individuals in the whiskey industry. “Cheese washer’s lung” has been reported in thewidespread cheese industry. Ironically, this condition is due to Penicillium spores. In the lumberindustry, “ maple bark stripper’s disease” results from the inhalation of fungus particles, particularlyCryptostroma. Bagassosis results from the inhalation of the bagasse dust left behind after the moisturehas been removed from sugar cane stalks. Once the disease is in progress, the worker must be removedfrom any further contact with the bagasse dust, or the symptoms are likely to return and will usuallyget progressively worse.In the textile industry, the inhalation of cotton dust and other organic fibers has long been associatedwith reactive airway disturbances known as byssinosis. Individuals with this condition complain ofchest tightness, wheezing, and other respiratory difficulties. It should be noted that these symptomsmight appear after a short, or even an extended, absence from the industrial setting. A particular patternseems to be that the first day back at work after a break, such as a weekend, is the most likely time foran episode. Unlike the previously cited occupational diseases, byssinosis does not appear to benecessarily related to the presence of bacteria, fungus, or some other living organism; the cotton ortextile dust is the only requirement. Bronchoconstriction results from the release of histamine and5-hydroxytryptamine following inhalation of the cotton dust. If the affected workers are removed fromthe environment containing the offending dusts relatively early in the process (i.e., months or very fewyears), then the patients appear to recover without permanent lung decrements. Long-term developmentof the disease, however, has been shown to result in permanent injury. In addition, the symptomsassociated with byssinosis are usually more severe in smokers than in nonsmokers.