Influenza B infection complicated by patent foramen ovale and high altitude pulmonary edema

A 34-year-old man presented to a clinic at a ski resort in the Rocky Mountains at 9000 feet (2743 m) with shortness of breath and fatigue, a few days after arriving to altitude from sea level. He was found to be hypoxic with radiographic findings consistent with high altitude pulmonary edema (HAPE). He was treated with high flow oxygen, steroids, and calcium channel blockers and transferred to a lower altitude tertiary care hospital for intensive care unit monitoring and further treatment. During his diagnostic evaluation, he was found to have both a patent foramen ovale and influenza B infection. While patent foramen ovale is a known risk factor for HAPE, there is also some evidence that upper respiratory tract infections in general and influenza in particular may also be risk factors for HAPE. The 2 diseases may share an underlying pulmonary pathophysiology, as both cause noncardiogenic pulmonary edema and alveolar hemorrhage. We report an unusual case of influenza B virus compounded by previously undiagnosed patent foramen ovale, travel to high altitude, and subsequent development of HAPE.