Journal of Wilderness Medicine 4, 286-292 (1993)

ORIGINAL ARTICLE

Acute mountain sickness in local pilgrims to a highaltitude lake (4154 m) in NepalBUDDHABASNYAT, MD

Himalayan Rescue Association, Nepal International Clinic, GPO Box 3596, Kathmandu, Nepal

There is a significant collection of literature on acute·mountain sickness (AMS) in foreign trekkersto Nepal. However, reports on altitude sickness among native Nepalis besides Sherpas is almostnon-existent. This is a preliminary study sponsored by the Himalayan Rescue Association of AMSamong pilgrims to a holy lake (Gosaikunda) at 4154 m in Nepal. The study was done using astandard AMS questionnaire form. It revealed that out of 5163 pilgrims who came to the lake, 229(4.4%) developed AMS. The severity of the illness correlated with the rapidity of ascent, but therewas no difference in severity between men and women. Five pilgrims who were ataxic were put inthe hyperbaric bag. Subjective improvement was noted in all five cases. This study of AMS amongnon-Sherpa pilgrims suggests that various Nepali ethnic groups may be just as vulnerable to AMS asare tourists.

Key words: acute mountain sickness, AMS, pilgrims, trekking

Introduction

Acute mountain sickness (AMS) occurs regularly among trekkers in the Himalayas [1].However, there is a paucity of data on AMS which occurs among the local Nepalipopulation. AMS is a symptom complex which usually afflicts people who ascend tooquickly to a high altitude without acclimatization [1,2]. Besides tourists who trek in theHimalayas and sometimes suffer from AMS, the staff at the Himalaya RescueAssociation aid posts in Pheriche and Manang (both in the Nepal Himalayas) regularlywitness native Nepali trekking support staff who suffer mild, moderate or severe AMS.This may progress to high altitude pulmonary edema (HAPE) or high altitude cerebraledema (HACE) [unpublished data, Himalaya Rescue Association 1989, 1990, 1991].Another little known but vulnerable group to AMS appears to be pilgrims who climbhigh mountain passes to shrines and holy lakes at significant altitudes. There are severalof these in Nepal and India, where thousands of pilgrims ascend each year, usually for aparticular religious festival. One of these locations is Gosaikunda lake in the LangtanNational Park region in Nepal, at an altitude of 4154 m. On August 25, 1991, over 5000pilgrims congregated to take a holy bath in the lake and pray to the Lord Shiva. Eightmedical students from the Tribhuban University Medical School in Kathmandu and twodoctors went along to study altitude sickness in this group.

0953-9859 © 1993 Chapman & Hall

287Mountain sickness in local pilgrims in Nepal

Methods

Almost all the pilgrims to Gosaikunda (4154 m) came via two routes: either throughDunche (1914 m) or via Sundarijal (1187 m). As the way to Dunche can be driven,many pilgrims prefer this route to Gosaikunda over the Sundarijal route, which is morecircuitous. Most of the people (166 or 72%) with AMS took two days to come up to thelakes. Within this schedule, the night stop for most people after day 1 from Dunche wasSing Gompa (3168 m). The study was done over August 24 and the morning of August25. Most people with AMS (174 or 76%) staggered in on the afternoon of August 24, asthe main day of the festival (lanai Purnima) was August 25, when the devotees took anearly morning dip in the lake and quickly headed down to a lower altitude. During thestudy period, there were 5163 pilgrims that came to the lake. There were some that cameafter dark or in the very early hours of the morning and could not be counted. Eightmedical students well versed in the symptomatology of altitude sickness observed thesepilgrims and used a standard AMS questionnaire [3] (Table 1), translated into Nepali bythe author. After several trial runs, the questionnaire was administered to those pilgrimswho appeared to have significant symptoms of altitude sickness (i.e., appeared to bevomiting, clasping their heads with severe headache or just appeared tired and listlesseven after 2 h rest).

There were 229 questionnaires completed after the pilgrims had rested for about 2 hafter their climb. If patients appeared very ill, they were referred to one of the doctors,who administered nifedipine or dexamethasone, and used the hyperbaric bag wherefeasible. The other doctor walked around the lakeside helping the medical students fillout questionnaires. Mild cases of altitude sickness were generally not counted, as almostevery pilgrim was going to descend the next day if he or she arrived on August 24, or thevery same day if arrival was on August 25. Two people on either side of the lake countedthe number of pilgrims as they came from the two approaches. Only people who indi­cated ataxia on the questionnaire required testing; the rest were verbal responses.

Table 1. AMS symptom questionnaire

Symptom Score Remarks

Headache 1 Transient, relieved with analgesic2 Severe, or not relieved with analgesic

Insomnia 1 Difficulty falling asleep, frequent waking

Dizziness 1

Ataxia 1 Difficulty maintaining balance2 Steps off line3 Falls to ground or cannot finish test

Severe lassitude 3 Requires assistance for tasks of daily living

Anorexia or nausea 1 True anorexia, not distaste for diet

Vomiting 2Dyspnea on exertion 2 Dyspnea forces frequent halts, slow to recover

At rest 3 Marked dyspnea at rest

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Table 2. Days of ascent and severity of AMS

Days

Basnyat

Severity

Mild (score 2-4)Moderate (score 5-11)Severe (score 12-18)

Total

1-2

2109

55

166

3-4

452

7

63

Total

616162

229

Mild altitude sickness was defined as a score between 2-4, moderate altitude sicknessas a score between 5-11 and severe altitude sickness as a score between 12-18. Themaximum score was 18. This system of scoring was followed by an earlier HimalayaRescue Association publication [4]. In the present study, however, the global functionpart of the questionnaire, which is an assessment by the questioner, was ignored.

Results

A total of 5163 pilgrims were counted. Of these 229 (4.4%) appeared to have altitudesickness; 6 (2.6%) had mild altitude sickness, 161 (70%) had moderate and 62 (27%)had severe altitude sickness (Table 1). Of the 5163 pilgrims 4343 (84%) came fromDunche side and 820 (16%) from the Sundarijal side. Although the age and sex of thetotal number of pilgrims were not determined, the severity of AMS by age and sex in thepilgrims to whom the questionnaire was administered is shown in Tables 3 and 4. Therewas no difference in severity between men and women. The average age of therespondents was 44 years, with a range between 14 and 78.

There were 36 people with AMS over the age of 60, out of which ten were over 70.Table 5 shows frequency and severity of illness in comparison to the days of ascent. Mostof the people with AMS (166 or 72%) took 2 days to walk up, while 63 people (28%)took 3 to 4 days to walk up. Only three people walked up from Sundarijal to the lake in 2days; all three suffered severe altitude sickness. Out of the minority of 63 people with

Table 3. Severity of AMS by sex

Severity Males Females Total

Mild 4 2 6Moderate 84 77 161Severe 25 37 62

Total 113 116 229

Mountain sickness in local pilgrims in Nepal

Table 4. Severity of AMS by age groups

Age (years)

Severity <20 <40 >40 Total

Mild 1 3 2 6Moderate 12 73 76 161Severe 4 15 43 62

Total 17 91 121 229

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altitude sickness who took 3 to 4 days to walk up to the lake, only four people came upfrom Sundarijal. Hence, almost all of the people with altitude sickness (96.9%) camefrom Dunche side. Pilgrims who walked for only 1 to 2 days had significantly morealtitude sickness than did those who walked up for 3 to 4 days (,,2, 11.2; P < 0.001).The pilgrims in the study included various ethnic groups (all residing around 1500 m),but did not include any Sherpas or other high altitude residents. Of the 229 people towhom questions were asked, 20 who appeared to be the sickest were referred to one ofthe doctors in the team who had access to dexamethasone, nifedipine and the hyperbaricbag. Five people were treated in the bag. There was no oxygen available.

The medical students asking the questions had a supply of acetazolamide, which wasgiven out to the pilgrims with moderate altitude sickness. All the referrals with severe

Table 5. Frequency of illness by days of ascent

No. ofdays

Illness 1-1.5 2 3 4 Total

Headache 1* 18 41 12 2 73Headache 2* 39 73 36 7 155Insomnia 11 73 22 3 109Dizziness 50 104 47 9 210Ataxia 1* 22 76 21 4 123Ataxia 2* 12 11 10 3 36Ataxia 3* 6 5 2 1 14Severe lassitude 46 72 38 6 162Anorexia and nausea 46 77 29 6 158Vomiting 15 25 13 2 55Dyspnea on exertion 52 107 41 7 207Dyspnea at rest 14 16 7 37Total persons observed 52 144 52 11 229

*SeeTable 1

290 Basnyat

AMS (as judged by the questionnaire) and the five people (who were very ataxic, eitherthey fell off the line or could not finish the tandem walking) were put in the bag. Theataxic people were put in the bag for 30 min; subjective improvement was obvious in allfive. The hyperbaric bag might have been very useful for many more individuals withsevere altitude sickness, but lack of manpower and time constraints prevented its use inall. Only three out of the 20 seen by the doctor in the referral area had crackles in thelung bases. Everyone with severe AMS was advised to descend promptly. Few peoplefollowed this advice, so many spent a restless night with vomiting and severe headache.On the morning of the 25th (the main day of the festival), everyone took a holy dip in thelake and headed down promptly. Two patients were reported to have died on the waydown. The team did not witness these deaths. Random questioning of the pilgrims forsymptoms of gastroenteritis did not reveal this problem to be present. Many ill pilgrimsreported that they saw various visions along the way to the lake.

Discussion

Over 5000 people came up to the lake. The majority came up in 1 to 2 days from lowaltitudes (1500 m) and therefore were at risk for suffering AMS. We are unaware of anypublished studies which have described people in such a large number ascending tomoderate high altitude for a short period (1 to 2 days) who were at grave risk for AMS.The total number of trekkers in the Mount Everest region for one year was about 6000some years ago. This number has increased, but these are visitors over a one-year timeperiod. As in trekkers [5], the rate of ascent in pilgrims was an important factor inproducing AMS. Pilgrims appear to be as determined as tourists in trying to reach theirfinal destination. Many pilgrims were literally carried up to the lake in spite of AMSsymptoms.

Before the road was built to Dunche, most people went to Gosaikunda fromKathmandu via the more circuitous Sundarijal route. As the pilgrims usually took moretime (4 days on average from Kathmandu) from Sundarijal, there probably were fewerpilgrims with altitude sickness at Gosaikunda. In the present study, only seven of 229persons with AMS came up from Sundarijal. Of the seven, three pilgrims came up in 2days. These three had severe altitude sickness compared with the others who had onlymoderate altitude sickness.

There were 46 people (20%) among the patients with AMS over the age of 60; this isprobably a higher number of older people with AMS than seen in regular tourists. InNepal, many people become pilgrims when they become old. What was fascinating in thisstudy was the severity of AMS. Of the group with altitude sickness, 27% had severeillness, which always calls for urgent therapy and rapid descent. Almost everybodydescended the next day after their holy dip. This early morning descent was probablylifesaving. Of the 20 patients with severe altitude sickness examined by a physician, onlythree had rales. This suggests that HAPE, which usually requires about 48 h to develop[6], may not have been clinically obvious even in those with severe illness. This is similarto the situation on Mount Rainier, where HAPE is uncommon [7] because of short expo­sure (less than 36 h) to altitude.

In the differential diagnosis of AMS, alcoholic hangover, exhaustion and dehydrationneed to be considered [8], especially in this study group which had climbed up rapidly tocelebrate a festival. However, questions were asked after at least 2 h of rest after

Mountain sickness in local pilgrims in Nepal 291

ascending. Gastroenteritis, a common problem in Nepal which could potentially causedehydration, was not a problem on random questioning of the pilgrims studied. None ofthe patients had a strong smell of alcohol on their breath to suggest acute hangover orintoxication mimicking AMS. Furthermore, most of the festivities occurred at night, afterquestioning had been completed for the day.

Pilgrims usually ascribed their symptoms of altitude sickness to certain plants andvegetation along the way to the lake. This is not an unusual concept, which dates back tothe 17th Century when Jesuit priests first came to Central Asia [9].

Although a specific question about visions was not included in the questionnaire, afew very ill pilgrims volunteered this information. It is possible that severe AMSbordering on RACE was causing some people to hallucinate.

The treatment with the hyperbaric bag was found to be subjectively beneficial in thefive pilgrims who had this treatment for as little as 30-45 min. Although there was nofollow up on the hyperbaric bag-treated patients, there were many requests throughoutthe night from other AMS-stricken individuals for the 'magic cure'.

The two reported deaths at lower altitude (about 3561 m) after descending from thelake could have been altitude related, as there were histories of extreme shortness ofbreath, severe headache and vomiting before coma ensued. There was no history ofsevere gastroenteritis to account for dehydration as the main cause of death in thesepatients.

A clear limitation of this study is that the number of pilgrims with altitude sickness islikely to have been significantly under estimated. What appeared as mild altitude sicknesswas ignored, except for six pilgrims who were thought to be sicker than the question­naires indicated.

It was felt that the team needed to concentrate on the relatively sicker pilgrims so thatthey would get preference to the limited stock of medications and the hyperbaric bag.There were also pilgrims who arrived late at night or in the early hours of dawn who werenot counted. The two doctors and eight medical students found it a daunting task to dealwith very sick pilgrims, because there were no other health personnel actively involved inlooking after the other health needs of the large congregation camped in very over­crowded conditions. Again, lack of manpower and time constraints made it difficult toassess RAPE in any great detail. Furthermore, the primary aim of this preliminary studywas to derive data from the questionnaire. It can be considered that the sheer magnitudeof altitude-sick pilgrims clearly caught the team by surprise. A more complete study withquestionnaires distributed to a greater, randomized number of pilgrims needs to be doneto reflect more accurately just how rampant altitude sickness is in the pilgrim population.

The pilgrims studied were from various (non-Sherpa) ethnic Nepalese backgrounds.This underscores the importance of teaching about AMS to all lowland trekking stafffrom agencies in Nepal who may be just as vulnerable as pilgrims to AMS during treks.

Acknowledgements

I thank Dr Susan Maybin and the eight medical students (Rajendra Koju, Dhan BahadurShrestha, Bijendra Rai, Jagat Chhetri, Prakash Karki, Shailesa MalIa, Sunil Shrestha andAkshya Gautam) who took part in this survey.

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