Toluene diisocyanate induced asthma: outcome according to persistence or cessation of exposure.

Abstract

Sixty patients with occupational asthma due to exposure to toluene diisocyanate (TDI) were re-evaluated, five years after the initial diagnosis had been confirmed by a specific bronchial provocation challenge. During both examinations the severity of asthmatic symptoms and the need for antiasthma treatment were graded and lung function tests, measurement of airway responsiveness to methacholine (PD15), and skin tests with common inhalant allergens were carried out. The evolution of the disease was established on the basis of the increase or decrease in asthmatic symptoms, requirements for medication, and FEV, and PD,5methacholine between the two examinations. At follow up 17 patients (group A, 28-3%) had carried on working in the same environment after relocation to jobs with only occasional exposure to TDI; 15 of them used protective respiratory devices. The remaining 43 (group B, 71-7%) avoided further inhalation of TDI by moving to another sector. Group A showed a significant decrease in FEV, and PD,5 methacholine and significant increases in the severity of symptom score and requirement for medication; 13 subjects (76 5%) were worse, four (23-5%) were stable, and no one had recovered or improved. Group B showed significantly less severe symptoms and a threefold increase in PD,5 methacholine; 12 subjects (28-2%) totally recovered, 10 (23 2%) improved, 16 (37 2%) were stable, and five (1 1-6%) were worse. In group B the duration of exposure to TDI and of symptoms before the initial diagnosis delineated the patients who recovered from those who did not improve; intermediate values in these features characterised the subjects who improved but did not recover. It is inferred that complete removal

Consequences of occupational asthma on employment and financial status: a follow-up study

“…Several studies have shown that occupational asthma can lead to permanent disability, even after removal from exposure to the occupational sensitizer [15,18]. However, it has been proved that subjects who stayed in the same job generally experienced a worsening of their asthma and an increase in nonspecific bronchial hyperresponsiveness [15][16][17]. Complete and early removal from exposure, therefore, remains the treatment of choice in patients with occupational asthma.…”

“…In the present study, at the time of follow-up, nearly one third of the patients were still exposed to the aetiological agents responsible for their asthma. Financial consequences were nil or minor but their condition was likely to worsen [15][16][17]. Two thirds of the patients were no longer exposed but most of them suffered a marked reduction of income.…”

Health Information in Material Safety Data Sheets for a Chemical Which Causes Asthma

“…The consequences of underrecognition of the asthmagenic properties of TDI are clinically important for the asthma patient, because sequelae of continued exposure may be severe and permanent. 27,29 If the worker can not tell from the MSDS that TDI may cause a serious health problem such as asthma, he or she may be less likely to use optimal safety procedures to prevent exposure. Similarly, the employer has to be informed that the product could harm workers before he or she will endorse safety procedures and authorize expenditures for exposure control.…”

Management of occupational asthma: cessation or reduction of exposure? A systematic review of available evidence

“…Of these 32 publications, 10 studies met the inclusion criteria and were included in the analysis (table 1) [11][12][13][14][15][16][17][18][19][20]. 22 articles were excluded for the following reasons: 1) lack of a comparison group of workers who avoided exposure [21][22][23][24][25][26][27]; 2) comparison with asymptomatic workers who remained exposed to the offending agent [28]; 3) serial assessments of the same or a portion of the same cohort of workers with OA due to red cedar dust [13,[29][30][31][32][33], isocyanates [34] or persulphate salts [35]; 4) failure to provide appropriate data on the outcomes of patients who had ''reduced exposure'' [36][37][38][39][40]; and 5) single case report [41].…”