Acute Mountain Sickness in Children at 4380 Meters in the Himalayas

Wilderness and Environmental Medicine, 20, 359 363 (2009) BRIEF REPORT Acute Mountain Sickness in Children at 4380 Meters in the Himalayas Santosh Pradhan, MB, BS; Sanjay Yadav, MD; Pritam Neupane, MD; Prajan Subedi, MD From the Mountain Medicine Society of Nepal (Drs. Pradhan, Yadav, Neupane, Subedi); and the Himalayan Rescue Association (Drs. Pradhan, Neupane, Subedi), Kathmandu, Nepal. Objective. To determine the incidence of and risk factors for acute mountain sickness () in native Nepalese children during a pilgrimage trip to Gosaikunda Lake in the Langtang National Park Region of Nepal (elevation 4380 m). Methods. A descriptive, noninterventional, cross-sectional study was completed on a group of children during the pilgrimage to Gosaikunda. Participants were interviewed about the symptoms of using the Lake Louise Scoring System. Results. Thirty-six children between 3 and 15 years of age were interviewed after a rapid ascent (over 1 to 3 days) from 1950 m to 4380 m. Acute mountain sickness was diagnosed in 17 of 36 (47.2%) children. The sickness was seen in only 5 of 20 (25%) children who took 2 or more days to ascend, compared with 12 of 16 (75%) children who spent only 1 night (reaching the study site at Gosaikunda on the second day) to complete the same ascent (P #.01, odds ratio [OR] 5 9.0, 1.61, OR, 57.36). No significant correlation was found between the incidence of and gender, previous exposure to high altitude, or concurrent illness. Conclusions. Our results indicate that the incidence of in this group of Nepalese children was high and associated with rapidity of ascent. Rapid ascent to high sleeping altitude and increased physical activity were observed as possible risk factors. We suggest organizing educational programs to make children and their parents aware of altitude-related problems and advise gradual ascent to such highaltitude pilgrimage sites. Introduction Each year thousands of lowland children travel to high altitude, often accompanying their parents on occupation-related trips, pilgrimages, or leisure activities (eg, trekking, skiing). 1 Although such travel to altitude usually occurs without incident, some children develop symptoms related to altitude illness or due to other adverse effects of travel on health. 2 Furthermore, although there has been extensive study of acute mountain sickness () in adult trekkers in the Nepalese Himalayas, 3 6 no data are yet available on the incidence of in Nepalese children. One study suggested that the incidence of in children seems to Presented as a poster at the Expedition Medicine Symposium, Royal College of Physicians of Edinburgh, Scotland, September 30, 2005. Corresponding author: Dr Santosh Pradhan, Specialty Registrar A&E, Flat 7, 3 Erleigh Road, Reading RG1 5LR, UK (e-mail: santos_h_p@yahoo.co.uk). be the same as that observed in adults, 7 but another study reported a negative correlation with age, suggesting that younger populations are more susceptible to. 3 So far there has been little work accomplished to evaluate possible risk factors for development of in children exposed to high altitude. On the full moon day of August, Janai Purnima, thousands of lowland-dwelling people ascend rapidly to a very high-altitude 8 location of Gosaikunda Lake in the Langtang National Park Region of Nepal (elevation 4380 m). 9,10 It is felt by many pilgrims that the path to enlightenment is difficult and that the more one suffers, the more one s sins are cleansed. Therefore, a rapid ascent is often preferred in such pilgrimages. A previous study performed involving individuals making this pilgrimage revealed a high incidence of in adults. 10 The purpose of this study was to determine the incidence of in Nepalese children making the same trek to 4380 m and to explore possible risk factors predisposing them to.

360 Pradhan et al Methodology DESIGN During the annual pilgrimage to Gosaikunda, the Himalayan Rescue Association (HRA) in Nepal organizes a free health camp to educate pilgrims on the risks of and to treat those suffering from mountain sickness and other travel-related illness. The authors, who volunteered as medical doctors in the health camp of August 2003, designed the questionnaire using the Lake Louise Scoring System (LLSS) for diagnosis of. The Nepal Health Research Council waived the Institutional Review Board review for this study. PARTICIPANTS The HRA team traveled from Kathmandu (1300 m) to set up the health camp at Gosaikunda (4380 m) 2 days before the Holy Full Moon day event and met with local leaders, district officials, and Red Cross Society and Army personnel to disperse information about mountain sickness and the study. All children and their parents who came into contact with the study team were invited to participate. The aim of the study was explained to the parents, and verbal consent for participation was obtained from parents and those children who were able to understand the information. No parents or children who came into contact with the team refused to be interviewed. We used a convenience sampling method and interviewed 36 children who had embarked on the holy walk from Dhunche (1950 m). Exclusion criteria were 1) children younger than 3 years of age, 2) children older than 15 years of age, 3) children not able to communicate verbally, 4) and children and parents who did not wish to participate in the survey. All children were interviewed on the evening before the full moon day and the subsequent morning (full moon day: August 12, 2003) at the study site (4380 m). PROTOCOL The participants were interviewed using a close-ended questionnaire designed to obtain demographic details (sex, age, and original habitat), information concerning rate of ascent (days taken to reach Gosaikunda, location of sleeping altitude, rest days, arrival time, and stay duration at the study site), intercurrent illness, previous exposure to altitude, smoking, and alcohol use (Appendix 1; available at www.wem.org). The participant s symptoms were recorded using the LLSS (Appendix 2; available at www.wem.org). Acute mountain sickness was defined by an LLSS score of $3 (headache plus at least 1 other symptom: Table 1. Demographics of children interviewed Age (in years) No. male No. female Total no. 5 7 2 1 3 7 9 4 3 7 9 11 6 4 10 11 13 7 5 12 13 15 2 2 4 Total no. 21 15 36 sleep disturbance, poor appetite/nausea/vomiting, dizziness, unusual fatigue) in the high-altitude setting and further classified into mild, moderate, and severe according to LLSS scores of 3 to 6, 7 to 9, and $10, respectively. Pulse oximetry was recorded, and clinical examination performed on 1 ataxic participant. STATISTICAL METHOD With data gathered from previous HRA health camps held at the same region, the incidence of in the group with the faster ascent rate was estimated to be 75%, with a 50% reduction in the slower ascent rate group. The sample size required to detect this difference with statistical significance of 5% and a power of 80% is 13 in each group (fast ascent vs slow ascent), with a minimum desired total recruitment of 29 participants (Epi Info Ver 3.4.1). Chi-square probability and Fisher s exact probability tests were used to analyze the data. Results The mean age of the interviewed children was 10.38 6 0.38 years (mean 6 SE) (Table 1). Seventeen of the 36 (47.2%) children interviewed had LLSS scores qualifying for. Of the remaining 19 children, 6 did not have any symptoms and 13 had some symptoms but did not qualify for. The usual first day stopover for nearly half of the children (n 5 16) was at Chandanbari (3000 m), already a gain of more than 1000 m from Dhunche (1950 m). The following day, 16 of 36 children who reached Gosaikunda (4380 m) had gone 1380 m further from the previous sleeping altitude, among which 12 (75%) developed after the rigorous uphill walk. Of the remaining 20 children, who spent 2 or more nights to complete the same trip (second night stay at Lauribina 3900 m), 5 children (25%) had. There was a significant association between rapidity of ascent and incidence of (chisquare test 5 8.916, df 5 1, P 5.003) (Figure). Of those children suffering from, 13 (76.47%) had mild and 3 (17.64%) had moderate (n 5 17). Severe was observed in 1 female participant

Acute Mountain Sickness 361 Table 3. Incidence of acute mountain sickness () and gender, previous exposure, and concurrent illness No. no No. Total no. Figure. (5.88%), who was found to be ataxic after 2 hours of rest. Her oxygen saturation was recorded as 76% by pulse oximetry. The severity of correlated with the rapidity of ascent. Children taking 2 or more nights to reach the site had less severe symptoms than those who reached the site after only 1 night (chi-square test 5 21.27, P #.01) (Table 2). Twenty-one participants (58.33%) of the study were male. No significant association was found between incidence of and gender (chi-square test 5 0.11, df 5 1, P 5.73) (Table 3). Previous exposure to high altitude was not associated with a decrease in incidence of (2-tailed Fisher s exact test, P 5 1). Additionally, no significant association could be found between concurrent illness and occurrence of (chi-square test 5 1.71, df 5 1, P 5.19). All 36 participants denied participating in smoking and alcohol consumption. Discussion Rate of ascent and acute mountain sickness. This work highlights for the first time the high rates of seen in low-altitude residents between 3 and 15 years of age ascending rapidly to high altitude for a religious pilgrimage. Data from previous study indicated that abrupt ascent to sleeping altitudes above 3000 m should be avoided. 5 In our study, pilgrims started to Gender Male 11 10 21 Female 8 7 15 Previous exposure to high altitude Yes 2 2 4 No 17 15 32 Concurrent illness Yes 15 10 25 No 4 7 11 ascend rapidly from 1950 m to a usual first-day sleeping altitude of 3000 m. On the second day, the sleeping altitude was either 3900 m or 4380 m, although a majority of the participants descended the same day, soon after reaching the holy site at 4380 m. This study is unique in that children rarely ascend rapidly to high altitude at one time in such a large number. The incidence of in children in a study at Lake Chungara (4400 m) in Northern Chile 11 was very high, explained by the fact that the participants were born at sea level and stayed in the high altitude for 24 hours. The incidence and severity of in our study would likely have been much higher if the participant s time of exposure to high altitude had been longer. Our study demonstrated that a rapid ascent from 1950 m to 4380 m and spending less than 2 nights was a major risk factor for developing. A previous study found an association between high levels of exercise and exertion during the early hours of altitude exposure and increase in incidence and severity of. 12 High levels of physical activity and exertion demonstrated by rigorous uphill scaling of 2430 m in 2 days or less combined with a significant altitude gained after a high sleeping altitude of more than 3000 m, as observed in our study, appear to Table 2. Rate of ascent and severity of acute mountain sickness () No. of nights stopped No LLSS score* 0 LLSS score 1 2 Mild Moderate Severe LLSS score 3 6 LLSS score 7 9 LLSS score $10 Total no. 1 1 3 11 0 1 16 2 11 3 1 3 0 18 3 1 0 1 0 0 2 Total 13 6 13 3 1 36 *LLSS 5 Lake Louise Scoring System.

362 Pradhan et al be possible risk factors for development. However, these factors need more exploration in specific studies. One prior study on adult pilgrims 10 conducted at Gosaikunda during an earlier pilgrimage season demonstrated a higher incidence of in females. In our study, both sexes showed an equal risk of developing at high altitude. In contrast to a study on hikers in the Mount Everest region, 6 no significant correlation was found between concurrent illness and increased incidence of in our study. While attending to pilgrims illness at the health camp, it was noticed that some had already developed symptoms of during their ascent, although they persisted on their journey, ignoring the general advice to ascend slowly and stay at the same altitude or descend in case of worsening symptoms. Some of the adult pilgrims had stated that they would rather die than descend without visiting the holy lake, thus failing in their devotional aim. Such devotion to their cause can be very hazardous and even fatal. 9,10 Our findings also provide insight into the cultural practices and beliefs associated with the pilgrims rush, which drive adults and children alike to go too high too fast. Some pilgrims appeared to mistake dizziness as an experience of spiritual revelation, while others believed the sensation was caused by the strong scent of wild flowers. Most recognized that such symptoms were common and felt they were to be expected on the trip. Few pilgrims linked these symptoms to the altitude or knew about preventive or treatment measures for. Because it was customary for pilgrims to fast during this trek, dehydration might also have exacerbated symptoms of 13 in some cases, although this was not studied. A recent study of 4- to 11-year-old children recommended that age-appropriate communication 14 be used to assess the presence of symptoms, particularly headache and gastrointestinal symptoms, and that the diagnostic threshold in this population may require modification. In our study, every effort was made to ensure that all children understood the questions asked about in their native Nepali language and that verification was obtained from their parents. It was difficult, however, to accurately assess the severity of symptoms in children. The major limitation of this study is the small number (n 5 36) of children interviewed during our 2 days of field study. Children were interviewed at a single altitude site (4380 m). It is possible that some children may have been too sick to make it to the study site and were, therefore, missed. Furthermore, children who did not have adequate symptoms at the time of the interview to qualify for might have developed worsening symptoms a few hours later or during their descent. The message from our study is that children and their accompanying parents should undertake a slow gradual ascent when traveling to such a high altitude. Although the ideal ascent rate in children still remains to be defined, it has been recommended to sleep no higher than 2000 m for children younger than 2 years of age and no higher than 3000 m for children 2 to 10 years of age. 15 However, this has been argued by some 16 to be too conservative, and in cases of pilgrim trips to very high altitudes, such as Gosaikunda, we strongly support their recommendations 16 that the focus should be on preventive measures, such as planning a careful graded ascent itinerary and parental education. Conclusions The incidence of in Nepalese children ascending rapidly to 4380 m is high (47.2%). The risk of and its severity is increased by rapidity of ascent. Rapid ascent to high sleeping altitude and increased physical activity are possible risk factors. Although the incidence of in children has been found to be similar to that in adults, recognition of symptoms can be difficult in younger children and infants. Institutions in Nepal, such as the HRA, the Home Ministry, and the Health Ministry, should organize regular educational programs to increase awareness, with a focus on reducing the ascent rate of pilgrims and improving the identification and management of. Acknowledgments We thank Professor Buddha Basnyat for his encouragement, support, and guidance on this study. The Himalayan Rescue Association, Nepal, deserves special thanks for overall organization of the health camp and logistic support for our study. We owe gratitude to Mr Bhuvan Acharya, Mr Lakpa Sherpa, and Mr Arun Amatya for their help in disseminating the study information. We are grateful to the lodge owners at Dhunche, Chandanbari, Lauribina, and Gosaikunda for their hospitality. We also thank Ms Fiona Genesi (Health Protection Scotland) for guidance in the article writing and Mr Chris Redman (Health Protection Scotland) for advice on statistical analysis. References 1. Pollard AJ, Niermeyer S, Barry P, et al. Children at high altitude: an international consensus statement by an ad hoc committee of the International Society of Mountain Medicine, March 12, 2001. High Alt Med Biol. 2001;2: 389 403. 2. Theis MK, Honingman B, Yip R, McBride D, Houston CS, Moore LG. Acute Mountain sickness in children at 2835 meters. Am J Dis Child. 1993;147:143 145.

Acute Mountain Sickness 363 3. Hackett PH, Rennie D, Levine HD. The incidence, importance and prophylaxis of acute mountain sickness. Lancet. 1976;2:1149 1154. 4. Kayser B. Acute mountain sickness in western tourists around the Thorang pass (5400 m) in Nepal. J Wilderness Med. 1991;2:110 117. 5. Murdoch DR. Altitude illness among tourists flying to 3740 meters elevation in the Nepal Himalayas. J Travel Med. 1995;2:255 256. 6. Murdoch DR. Symptoms of infection and altitude illness among hikers in the Mount Everest region of Nepal. Aviat Space Environ Med. 1995;66:148 151. 7. Yaron M, Waldman N, Niermeyer S, Nicholas R, Honigman B. The diagnosis of acute mountain sickness in preverbal children. Arch Pediatr Adolesc Med. 1998;152:683 687. 8. International Society of Mountain Medicine. Non-physician altitude tutorial. Available at: http://www.ismmed.org/ np_altitude_tutorial.htm. Accessed September 15, 2007. 9. Basnyat B. Acute mountain sickness in local pilgrims to a high altitude lake (4154 m) in Nepal. J Wilderness Med.1993;4:286 292. 10. Basnyat B, Subedi D, Sleggs J, et al. Disoriented and ataxic pilgrims: an epidemiological study of acute mountain sickness and high altitude cerebral edema at a sacred lake at 4300 m in the Nepal Himalayas. Wilderness Environ Med. 2000;11:89 93. 11. Moraga FA, Osorio JD, Vargas ME. Acute mountain sickness in tourists with children at Lake Chungara (4400 m) in Northern Chile. Wilderness Environ Med. 2002;13:31 35. 12. Roach RC, Maes D, Sandoval D, et al. Exercise exacerbates acute mountain sickness at simulated high altitude. J Apple Physiol. 2000;88:581 585. 13. Hackett PH, Roach RC. High altitude medicine. In: Auerbach PS, ed. Wilderness Medicine: Management of Wilderness and Emergencies. 3rd ed. St Louis, MO: CV Mosby; 1995:1 37. 14. Southard A, Niermeyer S, Yaron M. Language used in Lake Louise scoring system underestimates symptoms of acute mountain sickness in 4 to 11 year old children. High Alt Med Biol. 2007;8:124 130. 15. Pollard AJ, Murdoch DR, Bartsch P. Children in the mountains. BMJ. 1998;316:874 875. 16. Basnyat B, Sherpa N, Basyal G, Adhirikari P. Letters: children in the mountains. BMJ. 1998;317: 540. Address/Altitude Phone Number 2. Rate of ascent Where did you spend the night? (Place/no. of nights) Dhunche/1950 m Chandanbari/3000 m Lauribina/3900 m Gosaikunda/4380 m 3. Present illnesses Do you have any? (Yes/No) Troublesome cough Sputum Fever Loose stool Blood/mucus in stool Do you feel healthy to go on? 4. Past history Do you have any? (Yes/No) Asthma Cardiac disease Previous hospital admission Have you ever been to high altitudes? (Yes/No) If yes, where? (in meters) When? Were there any problems? (Yes/No) If yes, what were they? Lake Louise System Score 5. Drug history Are you taking any medication? (Yes/No) If yes, what? 6. Have you taken any alcohol? (Yes/No) If yes, how much? 7. Do you smoke? (Yes/No) Appendix 1: Questionnaire Gosaikunda Pilgrimage 2003 1. Identification Name Sex Age (Date of Birth) Appendix 2: Lake Louise Scoring System http://www.abdn.ac.uk/ src248/peru/documents/ams_scoring.doc (accessed March 31, 2009) Calculating the Lake Louise Scoring System Acute Mountain Sickness () Score 5 altitude gain and headache and at least 1 other symptom and a total score of $3 Self-Report Questionnaire