J Korean Med Sci.  1990 Dec;5(4):185-188. 10.3346/jkms.1990.5.4.185.

Significant changes of bronchial responsiveness to methacholine after early asthmatic reaction to toluene diisocyanate (TDI) in a TDI-sensitive asthmatic worker

  • 1Department of Chest Medicine, National Medical Center, Seoul, Korea.


Current asthma is often diagnostically excluded by the presence of normal bronchial responsiveness. We report on a TDI-induced occupational asthma patient with normal bronchial responsiveness. He had suffered from shortness of breath during and after TDI exposure for several months. His initial methacholine bronchial challenge test showed a negative response. The bronchoprovacation test with TDI showed an isolated immediate bronchoconstriction. The following methacholine bronchial challenge tests revealed that the bronchial hyperresponsiveness developed seven hours after the TDI challenge (methacholine PC20:5.1 mg/ml), progressed up until 24 hours, and returned to normal on the seventh day. This case provides evidence that the response of the airway to TDI may not always be accompanied by bronchial hyperresponsiveness to methacholine. Screening programs utilizing methacholine challenges may not always identify TDI-sensitized asthmatic workers.


Toluene diisocyanate; Occupational asthma; Bronchial hyperresponsiveness

MeSH Terms

Asthma/*chemically induced/diagnosis
Bronchial Provocation Tests
Bronchoconstriction/*drug effects
Methacholine Chloride/*diagnostic use
Occupational Diseases/*chemically induced
Skin Tests
Time Factors
Toluene 2,4-Diisocyanate/*adverse effects
Toluene 2,4-Diisocyanate
Methacholine Chloride
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