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Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options., (© 2024. Springer Nature Limited.)

Bhandari, Sanjeeb Sudarshan, Pranawa Koirala, Nirajan Regmi, and Sushil Pant. Retinal hemorrhage in a high-altitude aid post volunteer doctor: a case report. High Alt Med Biol. 18: 285-287, 2017.-High-altitude retinal hemorrhages (HARHs) are seen at altitudes more than 3000 m, are usually multiple, flame shaped, and adjacent to blood vessels. Development near the macula causes blurring of vision, otherwise, they are symptomless and self-limiting. They often develop during the first few days after ascent to high altitude and subjects often suffer from acute mountain sickness (AMS) or high-altitude cerebral edema (HACE). People going to high altitude for the first time are more susceptible to retinal hemorrhages than experienced climbers and high-altitude dwellers. We present a case of a 31-year-old male doctor who developed sudden unilateral blurring of vision without any other symptoms after 6 weeks of volunteering at a high-altitude aid post in Nepal. There were no features suggestive of AMS or HACE. All examinations were normal except for fundoscopic examination in the left eye, which determined macular retinal hemorrhage. Although he was reluctant to descend, he was counseled to descend and refrained from further ascent to higher altitude, which could accentuate hypoxemia and any strenuous activities that increase intraocular pressure. He recovered his vision after few weeks in Kathmandu and his retinal hemorrhages regressed. Hypoxia exacerbated by repeated bouts of rapid ascent to further higher altitudes may have contributed to his HARH. This suggests that unilateral retinal hemorrhages can develop even after several weeks at high altitude without concomitant AMS or HACE. People going to high altitude are reluctant to retreat, before reaching their target, when they suffer from HARH. The same is shown by a physician. So it is very important for healthcare professionals working at high altitudes especially in the Himalayas of Nepal to have a good knowledge about HARH and its proper treatment.

Ujka, Kristian, Rosa Maria Bruno, Luca Bastiani, Eva Bernardi, Paolo Sdringola, Nenad Dikic, Bikash Basyal, Sanjeeb Sundarshan Bhandari, Buddha Basnyat, Annalisa Cogo, and Lorenza Pratali. Relationship between occupational physical activity and subclinical vascular damage in moderate-altitude dwellers. High Alt Med Biol. 18:249-257, 2017., Background: Occupational physical activity (OPA) has been associated with increased cardiovascular (CV) events. The aim of this study was to investigate the association between OPA and markers of subclinical vascular damage among a moderate-altitude population living in the rural village of Chaurikharka (Nepal; 2600 m sea level)., Methods: Seventy-two individuals (age 42 ± 15 years, ranges 15-85 years, 23 men) were enrolled. Physical activity (PA) was evaluated using the International Physical Activity Questionnaire (IPAQ). Carotid-femoral pulse wave velocity (PWV), carotid ultrasound assessment, and flow-mediated dilation (FMD) were performed., Results: OPA was 9860 ± 5385 Metabolic Equivalent of Task (MET)-minutes/week, representing 77% of total energy expenditure, with 97% of the population performing high-intensity PA. In the univariate analysis, OPA was significantly associated with PWV (β = 0.474, p = 0.001) and carotid stiffness (CS) (β = 0.29, p = 0.019). In the multivariate analysis, including age, sex, oxygen saturation, mean blood pressure, low-density lipoprotein (LDL), and OPA, OPA remained an independent predictor of PWV (β = 0.403, p = 0.001) but not of CS (β = 0.028, p = 0.8). OPA remained an independent predictor of PWV independently from the Framingham risk score (FRS)., Conclusion: High-intensity OPA shows a positive, independent association with aortic stiffness in Himalayan moderate-altitude dwellers. This study suggests how vigorous OPA performed in moderate altitude may be a CV risk factor.