P150 The inhalation of silica nanoparticles may cause pleural effusion

Abstract

Occupational exposure to different inhaled nanoparticles such as silica and silicates has been associated with lung inflammation and pleural effusion.1 We hypothesize that some idiopathic pleural effusions may be secondary to inhaled silica nanoparticles. Objectives To evaluate the frequency of silica exposure in two groups of pleural effusion patients: idiopathic and with known aetiologies. To quantify the pleural fluid concentrations silica in the two groups of patients. Method A case-control study was designed based on our database of pleural effusions. Cases were defined as those categorized as idiopathic. These were frequency-matched by age and gender with controls which were diagnosed of malignant, cardiac or infectious pleural effusions. A telephonic survey consisting of questions about their professional life was performed and the exposed workers were identified. The silica was quantified by plasma atomic emission spectrometry analysis in a subgroup of patients. Results A total of 118 patients (74 men, with a median of 68 years-old) completed the survey. The percentage of exposed workers was 42% (IC95% 31%–55%) and 22% (IC95% 13%–34%) in case and control groups, respectively. The exposure-attributable fraction was 0.62 (IC95% 0.14–0.83). In the subgroup of 52 active working age patients ( Conclusion Patients with an idiopathic pleural effusion, particularly in the active working age, presented more risk of working in an environment with silica nanoparticles. High levels of silica were detected in this group of patients with an idiopathic pleural effusion. Reference Song Y, Li X, Du X. Exposure to nanoparticles is related to pleural effusion, pulmonary fibrosis and granuloma. Eur Respir J2009;34:559–67.