Incidence of high altitude pulmonary edema in low-landers during re-exposure to high altitude after a sojourn in the plains

Abstract

Incidence Pulmonary edema of mountaineers a b s t r a c tBackground: There is uncertainty whether acclimatized low-landers who return to high altitude after a sojourn at low altitude have a higher incidence of pulmonary edema than during the first exposure to high altitude. Methods: This was a prospective cohort study consisting of men ascending to 3400 m by road (N ¼ 1003) or by air (N ¼ 4178). The study compared the incidence of high altitude pulmonary edema during first exposure vs the incidence during re-exposure in each of these cohorts. Results: Pulmonary edema occurred in 13 of the 4178 entries by air (Incidence: 0.31%, 95% CI: 0.18%e0.53%). The incidence during first exposure was 0.18% (0.05%e0.66%) and 0.36% (0.2%e0.64%) during re-exposure (Fisher Exact Test for differences in the incidence (two-tailed) p ¼ 0.534). The relative risk for the re-exposure cohort was 1.95 (95% CI, 0.43%e8.80%). Pulmonary edema occurred in 3 of the 1003 road entrants (Incidence: 0.30%, 95% CI: 0.08%e0.95%). All three cases occurred in the re-exposure cohort. Conclusion: The large overlap of confidence intervals between incidence during first exposure and re-exposure; the nature of the confidence interval of the relative risk; and the result of the Fisher exact test, all suggest that this difference in incidence could have occurred purely by chance. We did not find evidence for a significantly higher incidence of HAPE during re-entry to HA after a sojourn in the plains.ª 2013, Armed Forces Medical Services (AFMS). All rights reserved.

Chemokines in High Altitude Pulmonary Edema

“…Moreover, HAPE is a rare disease with a reported incidence of 0.31 % in Northern Himalayas and incidences of HA related illnesses are known to reduce with acclimatization [12].This has been acknowledged by the authors as well. In a disease with such a low incidence, practical use of measurement of inflammatory markers for identification of individuals at risk of HAPE remains to be seen considering the extensive interaction between hypoxia-related and inflammatory chemical pathways [13] and wide arrays of inflammatory, infectious and other conditions which are likely to cause elevation of chemokines in participants [6].…”

Reply

“…We are pleased to receive such an early response to our paper comparing the incidence of high altitude pulmonary edema (HAPE) after the first exposure and after re-exposure to high altitude. 1 The letter gives us an opportunity to delve deeper and educate ourselves about finer points (for us) in epidemiology. It also commends our efforts in conducting this longitudinal study, and we express our thanks for this.…”

“…It appears like a black colored, thread-like eruption, closely mimicking cutaneous larva migrans. 1 It is a rare condition and since 1957 only 26 cases have been reported. 1,2 Most of the cases of CPM are reported from Asia; however, it has been rarely reported from India; one of the authors has reported a pediatric case of CPM.…”

“…1 It is a rare condition and since 1957 only 26 cases have been reported. 1,2 Most of the cases of CPM are reported from Asia; however, it has been rarely reported from India; one of the authors has reported a pediatric case of CPM. To the best of our knowledge, these are the first reported cases of CPM in the adult population, in India.…”

ROCK2 and MYLK variants and high-altitude pulmonary edema

“…HAPE is a rare disease, as acknowledged by the authors, and has an incidence of only 0.31% among Indian male lowlanders after an acute ascent (by air) to an altitude of 3,400 m in the Western Himalayas. 5 …”