High-Altitude Pulmonary Edema in Children in Mexico City: A Case Series

Marín, Alejandro Ferreiro, María Paula Ferreiro Soria, Karla Sánchez Olivera, Aranza Suárez Ortega, and Luis Martín Garrido García. High-altitude pulmonary edema in children in Mexico City: A case series. High Alt Med Biol. 00:00–00, 2026.—High-altitude pulmonary edema (HAPE) is a potentially life-threatening form of noncardiogenic pulmonary edema caused by hypobaric hypoxia. Although well characterized in adults, pediatric cases remain underrecognized and are frequently mistaken for pneumonia. We describe four pediatric patients aged 7–12 years diagnosed with HAPE at a Private Tertiary Referral Medical Center in Mexico City. One patient developed classic HAPE after ascent from low altitude, and three patients developed reentry HAPE after returning to high altitude following temporary stays near sea level. All patients presented with hypoxemia (SpO ₂ 77%–93%), respiratory symptoms, bilateral pulmonary infiltrates, absence of fever, and low inflammatory markers. Echocardiography demonstrated elevated or borderline elevated pulmonary artery pressures without structural heart disease. Supplemental oxygen resulted in rapid clinical improvement in all cases. Hospital stay ranged from 2 to 4 days, and none required mechanical ventilation. One patient experienced recurrence shortly after discharge. HAPE should be considered in children presenting with acute hypoxemic respiratory illness after recent ascent to high altitude. The combination of hypoxemia, bilateral infiltrates, low inflammatory markers, and rapid response to oxygen therapy may help distinguish HAPE from infectious pneumonia and facilitate timely treatment.