Occupational Asthma Reference
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Hendrick DJ, Marshall R, Faux JA, Krall JM,
Positive alveolar responses to inhalation provocation tests: their validity and recognition,
Thorax,
1980;35:415-427,
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Keywords: oa, as , ch, methods, alveolitis, bird, farmer, mushroom, hp, hypersensitivity pneumonitis, EAA, key, SIC
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Abstract
The validity of inhalation tests in the investigation of extrinsic allergic alveolitis was assessed from the results of 144 antigen and control tests in 31 subjects. A definitive pattern of positive late responses was observed. Reactions to nebulised bird serum and droppings in subjects with bird fancier's lung were identical to reactions after "natural" exposures in aviaries or lofts, and to reactions after "occupational" challenges in subjects with farmer's lung and mushroom worker's lung. In general, positive tests were easily recognised subjectively from symptoms and signs appropriate to an influenza-like illness and undue respiratory effort on exercise. They were associated with significant changes in six readily available objective monitoring measurements--exercise minute ventilation (greater than or equal to +15%), body temperature (> 37.2 degrees C), circulating neutrophils (greater than or equal to +2500/mm3), exercise respiratory frequency (greater than or equal to +25%), circulating lymphocytes (greater than ore equal to -500/mm3 with lymphopenia), and forced vital capacity (greater than or equal to -15%). These confirmatory monitoring tests had specificities of approximately 95% and sensitivities of 85-48%. Measurement of diffusing capacity, lung volume subdivisions, or resting minute ventilation/respiratory frequency proved to be too insensitive to be useful, as did auscultation and chest radiography. We conclude that responses that do provoke significant changes in these less sensitive tests are unnecessarily distressing and, presumable, unnecessarily hazardous.
Full Text
Comments
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two to nine hours and reached maximum intensities after between six and 20 hours of the start of exposure. In one subject with farmer's lung, symptoms began after about one hour, while in two avian reactors the onset of symptoms was delayed for 12-18 hours after the start of exposure. With both these avian reactors the maximum intensity of the symptoms experienced was not reached until the next day. All positive reactions were consequently of the "late" type, and all persisted for a minimum of several hours.
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