High-Altitude Pulmonary Edema at Moderate Altitude as First Manifestation of Pulmonary Hypertension in a 14-Year-Old Boy With Down Syndrome

To the Editor:

A 14-year-old otherwise healthy Scandinavian boy with Down syndrome (DS) accompanied his parents on summer vacation in the Austrian Alps. He had never been at moderate altitude before. Four hours after ascending to 2700 m altitude by cable car and moderate hiking on a plateau, he deteriorated clinically. His resting heart rate was 130 beats/min and his respiratory rate was 25 breaths/min. He had lung crackles on auscultation, his lips were blue, and he had disproportionately low oxygen saturation relative to moderate altitude (Sao₂ 70%). He was immediately taken back to the valley by cable car and improved rapidly after descent. All signs and symptoms of high-altitude pulmonary edema (HAPE) resolved within 1 hour. He did not return to moderate altitude again, and the rest of his vacation passed uneventfully.

Four years later, he developed increasing dyspnea at exercise and went through a thorough medical evaluation in his home country. Chronic pulmonary hypertension was diagnosed but without any evidence of primary heart disease. We suspect that HAPE may have been the first evidence of chronic pulmonary hypertension in this patient. Echocardiographic evaluation for possible evidence of pulmonary hypertension in this patient would have been interesting immediately after the occurrence of HAPE but was unfortunately not performed because he had recovered completely so quickly.

Congenital heart anomalies (15.8%) and pulmonary hypertension (7.8%) are common in patients with DS. ¹ Persistent pulmonary hypertension in patients without congenital heart disease has been reported but is a rare condition. ² Down syndrome is not considered a classical risk factor for primary pulmonary hypertension. A retrospective review by the Children's Hospital in Denver, CO, revealed a total of 52 children with HAPE, 6 of which also had DS. ³ Three of these children had chronic pulmonary hypertension, and 4 had either an existing cardiac defect with left-to-right shunt or previously had a defect with left-to-right shunt that had been repaired. One child had Eisenmenger syndrome with chronic right-to-left shunting of blood. Children with DS are living longer and are increasingly participating in recreational activities. Care should be taken in mountaineering with children with DS at altitude.