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.