[Pneumopathy due to isocyanate hypersensitivity: recognition as an occupational disease]

Hypersensitivity pneumopathies (HSP) are listed as number 66 in the list of occupational diseases but this list includes regulatory requirements that are not applicable to isocyanates. The authors report the case of a worker exposed to isophane di-isocyanate (IPDI) during the manufacture of polyurethane foam.

The diagnosis of HSP was based on the clinical presentation (dyspnoea, fever, crepitant rales) and the complimentary investigations (ground glass appearance on the thoracic CT scan, lymphocytosis in the broncho-alveolar lavage). It was confirmed by trans-bronchial biopsy. Only the functional assessment (airflow obstruction and absence of marked reduction in CO transfer) was atypical. With regard to the role of isocyanates the number of published cases (49 since the first observation in 1976) shows that this aetiology is rare. In the case presented the chronology of symptoms (regression following exclusion and immediate relapse following re-exposure) and the absence of exposure to other agents known to cause HSP confirm the aetiology with near certainty. This case was recognised within the framework of the complimentary procedure that allows for unlisted diseases.

In order to assist the management and recognition of HSP due to isocyanates there is good reason to raise the awareness of the medical profession and to extend the list of occupational diseases.