PNEUMOTHORAX RELATED TO AIR TRAVEL IN PULMONARY LYMPHANGIOLEIOMYOMATOSIS

Introduction Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting almost exclusively women and characterized by abnormal proliferation of smooth muscle cells (LAM cells) in the lungs, kidneys and axial lymphatics. In the lungs, LAM cell proliferation leads to the development of multiple thin-walled cysts resulting in the gradual onset of respiratory insufficiency and frequent pneumothorax (PT). Air travel (AT) could further increase the risk of PT in LAM through rupture of subpleural cysts induced by changes in atmospheric pressure in aircraft cabin. Methods To assess whether AT increases the risk of PT in LAM, we performed a retrospective surveyed of women members of European LAM patient associations. Data were collected through a questionnaire regarding the occurrence of PT episodes, including dates, affected side, and therapeutic modalities, as well as a list of AT after disease onset. A post-flight PT was defined as a PT diagnosed by a physician ≤ 30 days after AT. Flights performed after lung transplantation were withdrawn from the analysis. Results A total of 145 women responded to the survey. Their mean age was 48 ± 12 years. 207 episodes of PT were reported with a mean ± SD number of 2.5 ± 1.3 per patient. 128 patients with available dates allowed us to calculate the annual incidence of PT since the first symptoms attributable to LAM, and since LAM diagnosis which were respectively 7% and 5% (versus 0.006% in the general women population). 83 (57%) patients travelled by air. 75 patients with evaluable data performed a total of 191 AT. A PT occurred within 30 days after AT in 5/75 patients. One had bilateral PT. The probability of PT within 30 days after AT was 5/191 (2.6%) per patient, and 6/382 (1.6%) per lung. As compared to the 30 days before AT, the incidence of PT per lung was significantly higher during the 30 days after AT (RR 6, CI 1.02-113). In contrast, no difference in PT incidence was observed when comparing 2 other 30-days periods before and after AT. 2 Conclusions The incidence of PT in LAM is 1000 higher than in the general women population. The occurrence of PT increases significantly within 30 days after AT as compared to the 30 days before AT, suggesting that AT per se is a risk factor for PT occurrence in LAM