Complete bilateral spontaneous pneumothorax at moderate altitude revealing Marfan syndrome: a case report.

Background: Primary spontaneous pneumothorax (PSP) commonly occurs in young adults. However, simultaneous complete bilateral pneumothorax is rare and potentially fatal. Changes in barometric pressure associated with altitude exposure may precipitate pneumothorax in predisposed individuals, particularly those with unrecognized connective tissue disorders. Case Description: We report a case of a 17-year-old previously healthy male who developed sudden severe dyspnea while recreational skiing at a moderate altitude of 2,200 meters. Emergency on-site management required immediate bilateral needle decompression, followed by urgent hospital transfer. Imaging confirmed a complete bilateral pneumothorax with bilateral apical subpleural blebs. Sequential bilateral chest tube placement was performed, followed by staged bilateral video-assisted thoracoscopic surgery (VATS) with apical wedge resection and mechanical pleurodesis. Postoperative recovery was uneventful, with no recurrence during follow-up. Etiological investigations showed normal alpha-1 antitrypsin levels. Transthoracic echocardiography revealed a bicuspid aortic valve associated with moderate aortic regurgitation (grade 2/4). The combination of clinical, radiological, and cardiac findings ultimately led to the diagnosis of previously unrecognized Marfan syndrome. Conclusions: This case highlights complete bilateral spontaneous pneumothorax as a dramatic sentinel event revealing Marfan syndrome, potentially precipitated by moderate altitude exposure. It underscores the importance of systematic etiological evaluation in young patients presenting with severe or atypical pneumothorax and emphasizes the role of early multidisciplinary management to prevent life-threatening complications.