Abstract
Editorials
International aspects of the study of high altitude medicine and biology (p. 233)
We are fortunate that our area of science, high altitude medicine and biology, has such an international flavor. However recently there have been some worrying trends and we should do all we can to continue the free exchange of information.
Sightings, Edited by John W. Severinghaus (p. 236)
Clinician's Corner, Edited by Andrew Luks
High altitude retinal hemorrhages – an update
Retinal hemorrhages are very common at high altitude but fortunately usually do not produce sequelae. Bosch and colleagues (p. 240) update us on the pathophysiology and implications.
SCIENTIFIC ARTICLES
Comparison of scoring systems for assessment of acute mountain sickness
Wagner and coworkers (p. 245) discuss three commonly used scoring systems including the Lake Louise Self Report, the abridged version of the Environmental Systems Questionnaire, and a 100 mm visual analog scale. There was general agreement on the prevalence of AMS but there are significant differences in the results of the three systems.
The association of angiotensin-converting enzyme gene insertion/deletion polymorphisms with acute mountain sickness susceptibility: a meta-analysis
Luo and associates (p. 252) report on a meta-analysis of studies on the association between the ACE deletion and insertion alleles and AMS. Five studies with a total of 333 cases of AMS and 373 healthy controls were included. No significant differences in risk for AMS between carriers of the two alleles was found.
Periodic breathing, arterial oxyhaemoglobin saturation and heart rate during sleep at high-altitude
Insalaco and colleagues (p. 258) investigated the effects of acclimatization to high altitude on periodic breathing, arterial oxygen saturation and heart rate. Interestingly, whether periodic breathing was present or not did not alter the mean arterial oxygen saturation. The saturation increased with acclimatization and heart rate decreased.
Retinal vessel tortuosity in response to hypobaric hypoxia
MacCormick and others (p. 263) noted that retinal vascular tortuosity occurs in a number of pathological conditions but has not been systematically studied at high altitude. This report found that tortuosity increased rapidly at high altitude, and it was suggested that the cause was increased shear stress associated with elongation of the vessel segments.
Vitamin C supplementation does not improve hypoxia-induced erythropoiesis
Martinez-Bello and coworkers (p. 269) note that hypoxia increases the production of reactive oxygen species which may interfere with erythropoiesis. This study on rats was designed to determine whether Vitamin C administration improved erythropoiesis at high altitude. However no significant effect was found.
Mountaineering medical events and trauma on Denali, 1992–2011
McIntosh and colleagues (p. 275) carried out an extensive retrospective study of medical incidences and traumatic injuries on Mt. McKinley (Denali), a very popular climbing destination. The study included 24,079 climbers. Altitude-related symptoms were the most common illness category while frostbite was the commonest individual diagnosis. Surprisingly the only fatality in the series was due to brain injury following a fall.
BRIEF REPORT
Twice daily assessment of trekkers on Kilimanjaro's Machame route to evaluate the incidence and time-course of acute mountain sickness
We have published a number of reports of Acute Mountain Sickness during climbs of Kilimanjaro, a very popular destination. In this Brief Report, Meyer (p. 281) reports on the six-day Machame route and documents the very high incidence of AMS and severe AMS on the summit day. High Altitude Cerebral Edema occurred in four of twenty-eight trekkers. Trekking companies need to be more aware of potential problems.
CASE REPORTS
When “high” is not very high: High altitude pulmonary edema as first manifestation of sarcoidosis-related pulmonary hypertension
Brill and colleagues (p. 285) report on a previously healthy 41-year-old man who developed High Altitude Pulmonary Edema. However subsequently he developed mediastinal lymphadenopathy and a biopsy showed sarcoidosis. The edema was therefore interpreted as an early manifestation of sarcoidosis-related pulmonary hypertension.
Acute massive splenic infarction with splenic vein thrombosis following altitude exposure of a Srilankan male with undetected sickle cell trait
Abeysekera and coworkers (p. 288) report on a patient with acute splenic infarction at high altitude in Sri Lanka who had a previously undetected sickle cell trait. Apparently this is the first report of this condition from the South Asian region.
MEETING REPORTS
Learning from Hypoxia Signalling
Berra and Nunez-O'Mara (p. 291) report on a meeting on hypoxia signalling that took place in Bilbao, Spain, in April of this year. The meeting was organized by a working group from the European Cooperation in Science and Technology (COST). An impressive series of topics were discussed including the effects of hypoxia on neoplasms, stem cells, cellular metabolism, and cardiovascular events. The aim of these brief reports is to alert readers to advances which can then be followed up by using an Internet search or contacting the authors.
The Lung at High Altitude
The Second International LEH Symposium was held from April 18–20, 2012 with the title “The Lung at High Altitude: From Cellular Acclimatization to Clinical Disease.” The main topics included genetic changes in response to hypoxia, high altitude physiology, and clinical conditions with an emphasis on pulmonary hypertension. This meeting and the one briefly described above emphasize the burgeoning of interest in high altitude medicine and biology.
LETTER TO THE EDITOR
Pulmonary edema after complete avalanche burial
Sumann and colleagues (p. 295) report on a 48-year-old woman skier who was completely buried by an avalanche for some 20–30 minutes. She was evacuated by helicopter and during subsequent treatment developed severe dyspnea and pulmonary edema.