Pulmonary Thromboembolism at High Altitude in a Previously Healthy Adult: A Case Report.

Travel to high altitudes presents unique physiological challenges and can lead to various acute illnesses. Although pulmonary thromboembolism is infrequently documented in these settings, it can be life-threatening if unrecognized. A 54-year-old man with no known comorbidities developed sudden-onset shortness of breath and altered mental status while traveling at high altitudes. Initial evaluation revealed hypoxia, fever, and a markedly reduced ejection fraction on point-of-care ultrasound, with no deep vein thrombosis (DVT) on Doppler studies. Further imaging identified minimal pleural effusion and atelectasis on high-resolution computed tomography of the thorax. Despite a low clinical probability based on scoring systems and a negative D-dimer, clinical suspicion prompted a computed tomographic pulmonary angiography, which confirmed pulmonary thromboembolism in the right lower lobe pulmonary artery. Treatment with apixaban led to symptomatic improvement, and the patient was discharged in stable condition. This case highlights the need to consider pulmonary thromboembolism in the differential diagnosis of respiratory distress at high altitude, where hypoxia and other altitude-related factors may contribute to a hypercoagulable state.