On the Mountains: High Altitude Sickness in Nepal
Dhan Bahadur Gurung is from Okahri, a village situated on the top of a hill in the Lamjung District of western Nepal. Recently, he visited Dudh Pokhari, a lake located high up in the Gokyo region, at the height of 15,500 feet, where the river Chepe originates.
"It was in Janai Purnima, a festival of Hindus, three years back, when we planned to trek up to the holy lake to take holy dip in the lake and to pray to God," says Dhan Bahadur. "On the way, my wife was having severe headache and too fatigue to walk any longer. She also complained of nausea and could not converse properly. So I had to hire a horse to take her to the lake. Throughout the journey, she could not talk nor eat anything."
It was altitude illness that Dhan Bahadur's wife was suffering from. Although it might have proved fatal as she was taken to still higher altitude, causing the symptoms to worsen, they were fortunate and she survived the journey. They now live happily in the village with two sons.
Nepal is a mountainous country whose northern half is covered by the Himalayas and eight of the world's fourteen tallest mountains, all above 26,000 feet. Mount Everest, at 29,028 feet, is in Nepal's Himalayas, a challenging destination for mountaineers and trekkers alike. So Nepal has been a popular destination for mountain expedition, trekking, and recreation. The world famous trekking routes, like the Annapurna route, Khumbu region, and Lantang route attract thousands of people every year.
The mountains are also famous for their pilgrimage sites, including the Muktinath Temple (at 8,900 feet), Gosainkunda (at 14,000 feet), and Dudh Pokhari (15,500 feet). Every year, thousands of pilgrims climb up the high mountains to pray to their deities. Additionally, more than 100 million people live permanently at altitudes higher than 8,000 feet. Most are not aware of how to handle altitude illness.
Matiram Pun, a medical student who helped organize a health camp at Gosainkunda in summer of 2004, explained his altitude illness: "Right from the return of the night call, I could not sleep and felt nauseated, with throbbing headache with some dizziness! Perfect AMS [Acute Mountain Sickness]. I took medication for AMS after consultation with the medical doctor who was in the camp."
Matiram, who had been to Gosainkunda twice before, was victim of mountain sickness. No one is immune to the effects of AMS; neither the experienced, nor the physical healthy, nor medical personnel!
High altitude illness is a collective term for acute mountain sickness (AMS), high altitude cerebral edema (HACE) and high altitude pulmonary edema (HAPE). A cerebral and pulmonary syndrome, it starts showing symptoms in unacclimatized people above about 8,000 feet. Other acute problems develop too, including high altitude cough, gastroenteritis, snow blindness, and conjunctivitis.
As a person goes higher, the percentage of oxygen in the air remains constant, but the number of oxygen molecules per breath is reduced. At about 12,000 feet, the barometric pressure is only about 60% of what it is at sea level, and each breath will bring 40% fewer oxygen molecules.
The body must adjust to having less oxygen. Physiological changes, known as acclimatization, occur to enable the body to function optimally in the low oxygen environment and prevent altitude illness. Acclimatization can be achieved only through slow ascent. Height is definitely important, but it is speed that puts people at risk for mountain sickness.
The first symptom is a severe headache at high altitude in an otherwise healthy individual. The symptoms of AMS, HACE and HAPE (Table 1) are important to recognize and to prevent worsening.
The best test for moderate AMS is to have the person walk on a straight line heel to toe. A person with ataxia cannot walk in a straight line, suggesting they should immediately descend.
What Can You Do?
Shyam Bahadur, a 28-year-old porter from the middle hills employed by a trekking agency was paidoff, high on the Thorong-La, because was suffering AMS and could not continue carrying. He descended on his own in a snowstorm. He had classical symptoms of AMS and collapsed and died, two hours above the rescue post in Manang.
In spite of all the precautions that a person might take to acclimatize to altitude, they might still get the illness. In such situation one should stop the further ascent until the symptoms disappear. A large part of acclimatization occurs over the first few days at a given altitude but different people acclimatize at different rate. Alcohol, sleeping pills, and narcotic drugs all depress the respiratory drive, making it worse. Drugs like Dimox have been used efficaciously to buy time when descent is not possible immediately and to facilitate descent. A person with AMS should never be left alone.
Mountain Medicine and Future
Every year, more people go to high altitude, but, like Dhan Bahadur, the general population is not aware of how to prevent and treat altitude illness. As both pilgrims and tourists are determined not to return before completing their tour, it creates a problem in the face of increasing symptoms. Many pilgrims claim that once you undertake the pilgrimage, it does not bode well for your spiritual welfare to give up in the middle. Lack of awareness kills many people every year.
The Nepali government has conducted campaigns to increase awareness of altitude sickness among pilgrims. It is suggested that pilgrimage medicine needs to be incorporated into the broader framework of travel medicine to understand the problems faced by pilgrims. The porters, who form the majority of many treks and mountaineering expeditions, are also often naïve to the dangers of altitude sickness. Shyam died an early death either because no body knew the "golden rules" in high altitude or they were not following them, leaving Shyam to descend alone.
Basnyat B (2002) Pilgrimage medicine. British Medical Journal, 324: 745.
Duff J et al. (1998) The genesis of international porter protection group. 25th Anniversary of Himalayan Rescue Association. 17-20.
Glazer JL et al. (2005) Awareness of Altitude Sickness among a Sample of Trekkers in Nepal. Wilderness and Environmental Medicine. 16(3):132-8.
Subedi R, et al. (2004) Gosainkunda health camp-2004 ADA report. Page V.
Thank You to:
Govinda Basyal of the Himalayan Rescue Association, and Matiram Pun for providing photographs for this article.