An Autopsy Case of An Acute Exacerbation of Idiopathic Pulmonary Fibrosis Triggered by the Inhalation of a Waterproofing Spray

The Underlying Mechanism of Poisoning after the Accidental Inhalation of Aerosolised Waterproofing Spray

Waterproofing sprays can cause acute respiratory symptoms after inhalation, including coughing and dyspnoea shortly after use. Here, we describe two cases where persons used the same brand of waterproofing spray product. In both cases the persons followed the instructions on the product and maximized the ventilation by opening windows and doors; however, they still became affected during the application of the product. Products with the same batch number as that used in one case were tested for their effect on respiration patterns of mice in whole-body plethysmographs and lung surfactant function inhibition in vitro. The product was used in spraying experiments to determine the particle size distribution of the aerosol, both using a can from one case and a can with an identical batch number. In addition, the aerosols in the mouse exposure chamber were measured. Aerosol data from a small-scale exposure chamber and data on the physical and temporal dimensions of the spraying during one case were used to estimate the deposited dose during the spraying events. All collected data point to the spraying of the waterproofing product being the reason that two people became ill, and that the inhibition of lung surfactant function was a key component of this illness.

Waterproofing Spray-Associated Lung Injury Review: Differences between Cases of Early and Delayed Improvement of Waterproofing Spray-Associated Lung Injury

Waterproofing spray-associated lung injury (WALI) is an acute respiratory disorder characterized by bilateral diffuse lung injury on chest computed tomography (CT). In most cases, the symptoms and abnormal radiographic findings of WALI patients improve spontaneously over several days; however, some cases have persistent symptoms and abnormal shadows for >1 week. The distinctive features of each WALI are unknown. Herein, we present two new cases of WALI that we encountered in our hospital, and we previously reported two other cases of WALI. We examined the characteristics of WALI in our cases and 39 other cases of WALI definitively diagnosed and reported in PubMed and the Japan medical board with verifiable data during a 15-year period. We compared the clinical characteristics of the 22 cases in which the patients' symptoms were resolved within 1 week (early improvement) to those of the 21 cases in which the symptoms were resolved after >1 week (delayed improvement). The WALI cases with delayed improvement had significantly more shadowing that extended over the entire lung field and was not biased in intensity toward the upper or lower lung field. In addition, the serum white blood cell (WBC) counts and serum Krebs von den Lungen-6 (KL-6) levels differed significantly between the cases of early and delayed improvement of WALI.