Sub-acute occupational hypersensitivity pneumonitis due to low-level exposure to diisocyanates in a secretary

Abstract

There is virtually no information in the literature about the exposure levels needed to induce hypersensitivity pneumonitis (HP) by diisocyanates. The present study reports a case of occupational HP due to diisocyanates after low-level exposure.A 53-yr-old female never-smoker developed progressive shortness of breath on exertion, cough, fatigue and flu-like symptoms shortly after she began work as a secretary of a car body repair shop. A diagnosis of HP was made 2 yrs later, based on a restrictive ventilatory defect, a reticulonodular and discrete ground-glass pattern on high-resolution computed tomography, lymphocytosis in bronchoalveolar lavage and specific immunoglobulin G antibodies to diisocyanate human serum albumin conjugates in the patient's serum.The diagnosis was confirmed by recovery after exposure cessation and deterioration after reexposure. Ambient monitoring revealed air concentrations of different diisocyanate monomers below the detection limit in both the patient's work station and in front of the paint spray booths, with the exception of one measurement that showed 4,4-methylenediphenyl diisocyanate concentrations of 3 mg?m -3 in front of one booth (corresponding to a total reactive isocyanate group concentration of 1 mg?m -3 ).The present authors conclude that concentrations of diisocyanates far below current exposure limits may induce hypersensitivity pneumonitis in susceptible subjects.

Consort hypersensitivity pneumonitis

“…Further case reports without involvement of partners indicate that hypersensitivity pneumonitis may develop in subjects with minimal exposure [6,7]. The present case corroborates these rare observations and adds to present knowledge that allergen transported by hair or clothes may induce hypersensitivity pneumonitis in susceptible subjects.…”

Prevention Guidance for Isocyanate-Induced Asthma Using Occupational Surveillance Data

“…The most common work process presented here is exposure to automotive paints, a process that is well known to cause respiratory disease, (8,45,46) and that has been associated with two fatalities. (33,34) One of the indirect exposures presented here was for an automotive manager in a collision repair setting, and the case is similar to an indirectly exposed automotive secretary with hypersensitivity pneumonitis (HP), reported by Schreiber et al (9) High airborne exposure to MDI during truck bed lining application has been previously reported in Washington and we report two cases of asthma in truck bed applicators. (47) …”

Occupational Hypersensitivity Pneumonitis

“…21 Isocyanates are a well-recognized cause of occupational asthma; however, there are also a number of cases of HP in the literature that have been attributed to isocyanate exposure, and these include examples of both acute 22 and subacute or chronic disease. [23][24][25] Whether this represents a dual pathology or clinical manifestations of different ends of a single disease spectrum is unknown. Although the use of isocyanates is wide, cases have been most commonly reported in workers from car body repair shops.…”

“…Although the use of isocyanates is wide, cases have been most commonly reported in workers from car body repair shops. 23,24 Only a small proportion of exposed individuals go on to develop clinical disease; the relative importance of any intrinsic risk factors is poorly understood. Genetics are likely to play a key role in individual susceptibility; Camarena et al 26 demonstrated that specific MHC class II alleles were significantly associated with the presence of HP in pigeon breeders.…”