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Porters have accompanied trekkers and climbers to high altitude since the earliest expeditions in the Himalayas. As the existing body of knowledge on high-altitude medicine expands, the focus remains on trekkers or climbers. And published literature on medical problems in the large porter population remains sparse. It is well known that porters working at high altitude in the Nepal Himalayas are often lowland dwellers and are as prone to high-altitude illnesses such as acute mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema as the trekkers are. Other illnesses such as diarrhea, respiratory illnesses, and infections also occur in this population. In this review, studies reporting these findings will be discussed along with the local context of socioeconomic barriers to adequate health care for these porters. [ABSTRACT FROM AUTHOR]

Phillips, Lara, Buddha Basnyat, Yuchiao Chang, Erik R. Swenson, and N. Stuart Harris. Findings of cognitive impairment at high altitude: relationships to acetazolamide use and acute mountain sickness. High Alt Med Biol. 18:121-127, 2017. Objective: Acute mountain sickness (AMS) is defined by patient-reported symptoms using the Lake Louise Score (LLS), which provides limited insight into any possible underlying central nervous system (CNS) dysfunction. Some evidence suggests AMS might coexist with altered neural functioning. Cognitive impairment (CI) may go undetected unless a sensitive test is applied. Our hypothesis was that a standardized test for mild CI would provide an objective measure of CNS dysfunction, which may correlate with the symptoms of AMS and so provide a potential new tool to better characterize altitude-related CNS dysfunction. We compared a cognitive screening tool with the LLS to see if it correlated with CNS dysfunction. Methods: Adult native English-speaking subjects visiting Himalayan Rescue Association aid stations in Nepal at 3520 m (11,548 ft) and 4550 m (14,927 ft) were recruited. Subjects were administered the LLS and a slightly modified version of the environmental Quick mild cognitive impairment screen (eQmci). Medication use for altitude illness was recorded. Scores were compared using the Spearman's correlation coefficient. Data also included medication use. Results: Seventy-nine subjects were enrolled. A cut-off of three or greater was used for the LLS to diagnose AMS and 67 or less for the eQmci to diagnose CI. There were 22 (28%) subjects who met criteria for AMS and 17 (22%) subjects who met criteria for CI. There was a weak correlation ( r2 = 0.06, p = 0.04) between eQmci score and LLS. In matched subjects with identical LLS, recent acetazolamide use was associated with significantly more CI. Conclusion: Field assessment of CI using a rapid standardized tool demonstrated that a substantial number of subjects were found to have mild CI following rapid ascent to 3520-4550 m (11,548-14,927 ft). The weak correlation between the LLS and eQmci suggests that AMS does not result in CI. Use of acetazolamide appears to be associated with CI at all levels of AMS severity. [ABSTRACT FROM AUTHOR]

Religious pilgrims have been going to high altitude pilgrimages long before trekkers and climbers sojourned in high altitude regions, but the medical literature about high altitude pilgrimage is sparse. Gosainkunda Lake (4300 m) near Kathmandu, Nepal, and Shri Amarnath Yatra (3800 m) in Sri Nagar, Kashmir, India, are the two sites in the Himalayas from where the majority of published reports of high altitude pilgrimage have originated. Almost all travels to high altitude pilgrimages are characterized by very rapid ascents by large congregations, leading to high rates of acute mountain sickness (AMS). In addition, epidemiological studies of pilgrims from Gosainkunda Lake show that some of the important risk factors for AMS in pilgrims are female sex and older age group. Studies based on the Shri Amarnath Yatra pilgrims show that coronary artery disease, complications of diabetes, and peptic ulcer disease are some of the common, important reasons for admission to hospital during the trip. In this review, the studies that have reported these and other relevant findings will be discussed and appropriate suggestions made to improve pilgrims' safety at high altitude. [ABSTRACT FROM AUTHOR]

Berendsen, Remco R., Peter Bärtsch, Buddha Basnyat, Marc Moritz Berger, Peter Hackett, Andrew M. Luks, Jean-Paul Richalet, Ken Zafren, Bengt Kayser, and the STAK Plenary Group. Strengthening altitude knowledge: a Delphi study to define minimum knowledge of altitude illness for laypersons traveling to high altitude. High Alt Med Biol. 23:330–337, 2022. Introduction: A lack of knowledge among laypersons about the hazards of high-altitude exposure contributes to morbidity and mortality from acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) among high-altitude travelers. There are guidelines regarding the recognition, prevention, and treatment of acute-altitude illness for experts, but essential knowledge for laypersons traveling to high altitudes has not been defined. We sought expert consensus on the essential knowledge required for people planning to travel to high altitudes. Methods: The Delphi method was used. The panel consisted of two moderators, a core expert group and a plenary expert group. The moderators made a preliminary list of statements defining the desired minimum knowledge for laypersons traveling to high altitudes, based on the relevant literature. These preliminary statements were then reviewed, supplemented, and modified by a core expert group. A list of 33 statements was then presented to a plenary group of experts in successive rounds. Results: It took three rounds to reach a consensus. Of the 10 core experts invited, 7 completed all the rounds. Of the 76 plenary experts, 41 (54%) participated in Round 1, and of these 41 a total of 32 (78%) experts completed all three rounds. The final list contained 28 statements in 5 categories (altitude physiology, sleeping at altitude, AMS, HACE, and HAPE). This list represents an expert consensus on the desired minimum knowledge for laypersons planning high-altitude travel. Conclusion: Using the Delphi method, the STrengthening Altitude Knowledge initiative yielded a set of 28 statements representing essential learning objectives for laypersons who plan to travel to high altitudes. This list could be used to develop educational interventions. [ABSTRACT FROM AUTHOR]

High-altitude illness is the collective term for acute mountain sickness (AMS), high-altitude cerebral oedema (HACE), and high-altitude pulmonary oedema (HAPE). The pathophysiology of these syndromes is not completely understood, although studies have substantially contributed to the current understanding of several areas. These areas include the role and potential mechanisms of brain swelling in AMS and HACE, mechanisms accounting for exaggerated pulmonary hypertension in HAPE, and the role of inflammation and alveolar-fluid clearance in HAPE. Only limited information is available about the genetic basis of high-altitude illness, and no clear associations between gene polymorphisms and susceptibility have been discovered. Gradual ascent will always be the best strategy for preventing high-altitude illness, although chemoprophylaxis may be useful in some situations. Despite investigation of other agents, acetazolamide remains the preferred drug for preventing AMS. The next few years are likely to see many advances in the understanding of the causes and management of high-altitude illness. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses the use of acetazolamide for preventing acute mountain sickness (AMS).

Objective: To evaluate the efficacy of ginkgo biloba, acetazolamide, and their combination as prophylaxis against acute mountain sickness. Design: Prospective, double blind, randomised, placebo controlled trial. Setting: Approach to Mount Everest base camp in the Nepal Himalayas at 4280 m or 4358 m and study end point at 4928 m during October and November 2002. Participants 614 healthy western trekkers (487 completed the trial) assigned to receive ginkgo, acetazolamide, combined acetazolamide and ginkgo, or placebo, initially taking at least three or four doses before continued ascent. Main outcome measures: Incidence measured by Lake Louise acute mountain sickness score ≥3 with headache and one other symptom. Secondary outcome measures included blood oxygen content, severity of syndrome (Lake Louise scores ≥5), incidence of headache, and severity of headache. Results: Ginkgo was not significantly different from placebo for any outcome; however participants in the acetazolamide group showed significant levels of protection. The incidence of acute mountain sickness was 34%for placebo, 12%for acetazolamide (odds ratio 3.76,95%confidence interval 1.91 to 7.39, number needed to treat 4), 35% for ginkgo (0.95,0.56 to 1.62), and 14%for combined ginkgo and acetazolamide (3.04,1.62 to 5.69). The proportion of patients with increased severity of acute mountain sickness was 18%for placebo, 3%for acetazolamide (6.46,2.15 to 19.40, number needed to treat 7), 18% for ginkgo (1,0.52 to 1.90), and 7%for combined ginkgo and acetazolamide (2.95,1.30 to 6.70). Conclusions: When compared with placebo, ginkgo is not effective at preventing acute mountain sickness. Acetazolamide 250 mg twice daily afforded robust protection against symptoms of acute mountain sickness. [ABSTRACT FROM AUTHOR]

Hüfner, Katharina, Fabio Caramazza, Evelyn R. Pircher Nöckler, Agnieszka E. Stawinoga, Paolo Fusar-Poli, Sanjeeb S. Bhandari, Buddha Basnyat, Monika Brodmann Maeder, Giacomo Strapazzon, Iztok Tomazin, Ken Zafren, Hermann Brugger, and Barbara Sperner-Unterweger. Association of pre-existing mental health conditions with acute mountain sickness at Everest Base Camp. High Alt Med Biol. 23:338–344, 2022. Background: Mental health disorders are common, but limited data are available regarding the number of people with a past medical history of psychiatric diagnoses going to high altitude (HA). It is also unknown whether mental health conditions are associated with an increased risk of acute mountain sickness (AMS). Methods: We analyzed data from a previous study at Everest Base Camp. Participants self-reported their past medical history and history of substance use and had a brief history taken by a physician. AMS was assessed using the self-reported 2018 Lake Louise AMS Score. Results: Eighty-five participants (66 men and 19 women, age 38 ± 9 years) were included. When questioned by a physician, 28 participants reported prior diagnoses or symptoms compatible with depression (23%), anxiety disorder (6%), post-traumatic stress disorder (1%), and psychosis/psychotic experiences (9%). The prevalence of psychiatric diagnoses in the past medical history was much lower in the self-reported data (2/85) compared to data obtained via physician assessment (28/85). Increased risks of AMS were associated with a past medical history of anxiety disorder (odds ratio [OR] 22.7; confidence interval [95% CI] 2.3–220.6; p < 0.001), depression (OR 3.6; 95% CI 1.2–11.2; p = 0.022), and recreational drug use ever (OR 7.3; 95% CI 1.5–35.5; p = 0.006). Conclusions: Many people who travel to HA have a past medical history of mental health conditions. These individuals have an increased risk of scoring positive for AMS on the Lake Louise Score compared with people without a history of mental health conditions. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor about general medical knowledge in South Asia, with an example of Harrison's "Principles of Internal Medicine,' not having an entry for altitude sickness.

Discusses health risks facing pilgrims visiting religious sites in the Himalayas. Risk of mountain sickness, pulmonary oedema and cerebral oedema; Belief of the pilgrims that their symptoms are caused by the scent of flowers; Use of steroids to treat the pilgrims; Suggestion that pilgrimage medicine needs to be incorporated into the broader framework of travel medicine.

Presents case report on acute medical problems at high altitude. Case of mountain climber who presented with symptoms of severe abdominal pain and tenderness; Results of investigations; Discussion of mesenteric venous thrombosis in high altitude climber presenting with acute abdomen.

Background: The pathophysiology underlying acute mountain sickness (AMS) and excessive hypoxemia at high altitudes is not fully understood. Previous work by our group has demonstrated a significant association between urinary measures of dehydration and bicarbonate retention in subjects developing excessive hypoxemia and AMS at high altitudes. To further characterize these findings, we returned to our original testing site to examine the hypothesis that subjects with lower levels of oxygen saturation and/or AMS would possess higher levels of venous bicarbonate. Methods: Medical history inquiry, clinical examination. Lake Louise scoring, and the collection of venous levels of bicarbonate concentration and base excess were performed on 52 lowland-dwelling persons after they completed a religious pilgrimage in the Nepal Himalayas to approximately 4,250 m. Results: Oxygen saturation levels were strongly and inversely correlated with serum levels of venous bicarbonate and base excess, whereas AMS and Lake Louise scores were not associated with these measures of alkalosis. Conclusions: Our data suggest an association between measures of serum bicarbonate anion retention and decreasing oxygen saturation. Our data do not demonstrate an association between AMS or Lake Louise scores and measures of serum bicarbonate level. We propose that excessive hypoxemia at high altitudes may be associated with a compromised ability of the kidney to metabolically compensate for an altitude-induced hypocapnic alkalosis. [ABSTRACT FROM AUTHOR]

Background: The number of tourists in Nepal doubled between 2003 and 2013 is nearly 800 000. With the increased popularity of trekking, the number of those with pre-existing medical conditions requiring access to healthcare is likely to increase. We therefore sought to characterize the demographics and health status of trekkers on the Everest Base Camp route in the Solukhumbu Valley. In addition, we report cases that illustrate the potential complications of an ageing and medicated population of trekkers with underlying diseases.Methods: Trekkers over 18 years were enrolled in a larger observational cohort study on blood pressure at high altitude at 2860 m. They answered a questionnaire regarding demographics, medical history and current medications. Acute medical problems relating to medication use that were brought to the attention of investigators were documented and are presented as case reports.Results: We enrolled 670 trekkers, 394 (59%) male, with a mean age of 48 years (range 18-76). Pre-existing medical conditions were reported by 223 participants (33%). The most frequent conditions included hypertension, hypercholesterolemia, migraines and thyroid dysfunction. A total of 276 participants (41%) reported taking one or more medications. The most common medications were acetazolamide (79, 12%), antihypertensives (50, 8%) and NSAIDs (47, 7%), with 30 classes of drugs represented. Excluding acetazolamide, older trekkers (age >50 years) were more likely than younger ones to take medications (OR = 2.17; 95% CI 1.57-3.00; P <0.05). Acetazolamide use was not related to age.Conclusions: Our findings illustrate a wide variety of medical conditions present in trekkers in Nepal with wide-ranging potential complications that could pose difficulties in areas where medical care is scarce and evacuation difficult. Our cases illustrate the potential problems polypharmacy poses in trekkers, and the need for local and expedition healthcare workers to be aware of, and prepared for the common medical conditions present. [ABSTRACT FROM AUTHOR]