ORIGINAL ARTICLE A cluster of lung injury associated with home humidifier use: clinical, radiological and pathological description of a new syndrome Sang-Bum Hong, 1 Hwa Jung Kim, 2 Jin Won Huh, 1 Kyung-Hyun Do, 3 Se Jin Jang, 4 Joon Seon Song, 4 Seong-Jin Choi, 5 Yongju Heo, 5 Yong-Bum Kim, 6 Chae-Man Lim, 1 Eun Jin Chae, 3 Hanyi Lee, 7 Miran Jung, 8 Kyuhong Lee, 5 Moo-Song Lee, 2 Younsuck Koh, 1 Korean Unknown Severe Respiratory Failure Collaborative, the Korean Study Group of Respiratory Failure ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ thoraxjnl-2013-204135). For numbered affiliations see end of article. Correspondence to Professor Younsuck Koh, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Pungnap-dong, Songpa-Ku, Seoul, South Korea; yskoh@amc.seoul.kr Received 7 July 2013 Revised 1 January 2014 Accepted 9 January 2014 To cite: Hong S-B, Kim HJ, Huh JW, et al. Thorax Published Online First: [ please include Day Month Year] doi:10.1136/thoraxjnl- 2013-204135 ABSTRACT Background Over a few months in the spring of 2011, a cluster of patients with severe respiratory distress were admitted to our intensive care unit (ICU). Household clustering was also observed. Extensive laboratory investigations failed to detect an infectious cause. Methods Clinical, radiological and pathological investigations were conducted and the Korean Center for Disease Control performed epidemiological studies. Results The case series consisted of 17 patients. Their median age was 35 (range 28–49) years. Six were pregnant at presentation and four had given birth 2 weeks previously. All presented with cough and dyspnoea. In the majority of patients (14/17), multifocal areas of patchy consolidation were identified in the lower lung zones on the initial CT. As the condition progressed, the patchy consolidation disappeared (10/13) and diffuse centrilobular ground-glass opacity nodules started to predominate and persist. Pathological specimens (11/17) showed a bronchiolocentric, temporally homogenous, acute lung injury pattern with sparing of the subpleural and peripheral alveolar areas. Ten patients required mechanical ventilation, eight of whom subsequently received extracorporeal life support. Four of the latter underwent lung transplantation. Five of the six patients in the ICU who did not receive lung transplantation died. An epidemiological investigation revealed that all patients had used humidifier disinfectants in their homes. Conclusions This case series report showed that lung injury and respiratory failure can occur as a result of inhaling humidifier disinfectants. This emphasises the need for more stringent safety regulations for potentially toxic inhalants that might be encountered in the home. INTRODUCTION Starting in February 2011, a cluster of young adults were admitted to the intensive care unit (ICU) of a tertiary care hospital in Seoul with severe respira- tory distress. They were previously healthy without a history of respiratory or systemic diseases. The patients were uniformly refractory to therapy, which included antiviral agents and immunosup- pressive agents. The condition progressed until death or lung transplantation in many cases. Extensive laboratory investigations failed to find the aetiology. The authors had not encountered the disease previously and had not seen any reports of a similar condition in the literature. Due to the dreadful nature of the disease, the authors reported the cases to the Korean Center for Disease Control (KCDC) and consulted with domestic colleagues via the Korea Research Group for Respiratory Failure, which is a nationwide network of Korean intensivists. Through these efforts, several other patients in other regions of the country were identi- fied, after which they were transferred to the authors’ institution. During this process, the authors became aware that there were also infant cases and clusters of familial cases. METHODS The authors organised and chaired several multidis- ciplinary conferences that were attended by pulmo- nologists, radiologists and pathologists. The clinical manifestations, high-resolution CT observations, and the findings of various pathology specimens (video-assisted throracoscopic surgery biopsies taken for initial diagnosis, the lungs after they were explanted for transplantation, and autopsy lungs) of the cases were studied closely so that the disease, Key messages What is the key question? What was the main cause of the respiratory disease in the cluster of mostly peripartum women who were admitted to hospital in the spring of 2011 in South Korea? What is the bottom line? We report for the first time a case series of 17 patients with lung injury and respiratory distress associated with the use of home humidifiers. Why read on? This tragic cases series indicates that more stringent safety regulations are needed to protect the public from toxic inhalants at home. Hong S-B, et al. Thorax 2014;0:1–9. doi:10.1136/thoraxjnl-2013-204135 1 Critical care Thorax Online First, published on January 28, 2014 as 10.1136/thoraxjnl-2013-204135 Copyright Article author (or their employer) 2014. Produced by BMJ Publishing Group Ltd (& BTS) under licence. group.bmj.com on February 6, 2014 - Published by thorax.bmj.com Downloaded from