Simultaneous Presentation of Swimming-Induced Pulmonary Edema in a Set of Monozygotic Twin Elite Maritime Warfare Candidates: A Novel Case Report

Swimming-induced pulmonary edema (SIPE) is an incompletely understood condition that is often seen in U.S. special operations candidates participating in maritime qualification training courses. We present a case of two monozygotic twins with the simultaneous onset of acute respiratory distress during a crucible event of a maritime assessment and selection course. Subsequent pulmonary ultrasonography in both candidates showed wedge-shaped hyperechoic lines (B-lines) extending from the pleural interface into the interstitium. Chest radiography of both candidates revealed bilateral asymmetric hazy opacities consistent with SIPE. Both candidates recovered with supportive measures but were medically removed from training. Given the near-identical exposures of the candidates to the same ambient and water temperatures, duration of water submersion, magnitude of physical stressors, and viral colonization, this case study suggests that there may be underlying genetic factors, in addition to environmental factors, that predispose individuals to developing SIPE. Further benchtop and clinical research must be performed to identify potential genetic polymorphisms that contribute to the development of SIPE and to investigate safe interventions that address the underlying etiologies of SIPE pathophysiology.