Acute Mountain Sickness

Altitude sickness, also known as acute mountain sickness (AMS), altitude illness, hypobaropathy, or soroche, is a pathological effect of high altitude on humans, caused by acute exposure to the low partial pressure of oxygen at high altitude. It commonly occurs above 2,400 meters (8,000 feet). It presents itself as a collection of nonspecific symptoms, resembling a case of flu, carbon monoxide poisoning, or a hangover. It is hard to predict who will be affected by altitude sickness, as there are no specific factors that define people's susceptibility to it. Most people can climb up to 2500 meters (8000 ft) normally, after that, it is an open book. Extreme fitness does not guarantee you will escape it.

Acute Mountain Sickness generally happens when our body fails to acclimatize to the decreasing amount of oxygen available at high altitudes as we ascend above 2500 meters. Nepal Spirit Adventure trip itineraries have been professionally designed to minimize the effects of altitude sickness. All our group leaders/guides are well-trained to recognize any symptoms and to act accordingly on the spot. However, we do recommend you get informed about the dangers of altitude by seeking personal advice from your doctor or health advisor before coming to Nepal.

You can be totally confident that when you travel with us the safety and the well-being of our individual trekkers and groups are of primary importance to us. All of our trips are guided by qualified professional guides who are very well-trained by the Nepalese government. Our job is to ensure your comfort and safety as we take you wherever you want to go. Whatever trip you are interested in, we will always give clear, concise information relevant to a traveler's health, the locality, climate, food, etc.

Your worries about trekking to high altitudes can be put to rest as our guides are all trained in mountain safety and first aid and will keep a very close eye on you. We design our treks/tours to ensure our clients have enough time to acclimatize, and can quickly arrange alternative itineraries the moment we notice someone is not responding well. We are in constant communication with our field staff and monitor all aspects of government policy and weather that might affect your trip.

You can rest assured that Nepal Spirit Adventure has one of the best safety nets available, we are on-call 24 hours a day, and in the case of an emergency, helicopter rescue is available. We give the utmost consideration to your health and comfort. We carefully take care of all aspects of hygiene and food preparation and provide the most suitable equipment for each of the four seasons.

Safe, enjoyable travel is the prime objective of Nepal Spirit Adventure and we achieve that by providing a combination of accurate and detailed preparation while establishing realistic expectations. With these things in mind, we work honestly and effectively to provide you with the Himalayan experience that you want. We encourage you to question us freely and actively participate in the planning stages of your adventure trips.

Guidelines for Prevention of Acute Mountain Sickness (AMS)

  • Allow for sufficient rest days during your trek for acclimatization (After 3000 meters).
  • Do not make a rapid ascent, go too far, or too fast.
  • No Alcohol, Sleeping pills, or Smoking.
  • Drink more fluid than you usually do, 3 to 4 Liters a day of clean water, either boiled or treated on top of / tea/coffee/soup/juice, etc.
  • Climb high and sleep low.
  • Do not trek alone, take a guide/porter.
  • Listen to and follow the advice given by your group leader and guides.
  • Descend immediately if mild symptoms rapidly get worse, even if at night.
  • Never leave a sick person alone or let them descend by themselves.
  • Avoid getting cold.
  • AMS is common above 3000m and presents itself in the following ways:
  • Acute Mountain Sickness (AMS) is very common and is not life-threatening
  • HACE (High Altitude Cerebral Edema) is a life-threatening illness that can develop from AMS
  • HAPE (High Altitude Pulmonary Edema) is a life-threatening illness, it may occur on its own or at the same time as AMS or HACE

AMS Symptoms and Signs You Should Expect, (but not worry about)

  • Headache (typically throbbing, often worse for bending over or lying down), PLUS one or more of the following symptoms:
  • Tiredness, weakness
  • Dizziness, lightheadedness
  • Loss of appetite, nausea (or vomiting)
  • Insomnia, disturbed sleep, frequent waking
  • Treatment
  • Rest (avoid even the slightest exertion if this is possible) at the same, or even better at a lower altitude until the symptoms clear (up to 4 days)
  • Drink enough to keep your urine pale and plentiful
  • Use ibuprofen or paracetamol for headache
  • Consider taking Diamox (125 to 250 mg 12-hourly) for 3 days or for the rest of the time at altitude if symptoms return.
  • Consider using an anti-emetic (medications that prevent nausea & vomiting) for persistent nausea/vomiting symptoms
  • If AMS symptoms are severe, give oxygen (1 to 2 L/min) OR use a pressure bag until symptoms clear
  • Check the victim regularly for signs of HAPE and HACE, especially during the night
  • Important: ?f symptoms of AMS do not improve or get worse, descend far enough to clear symptoms (at least 500m/1640ft)
  • Facts on HAPE & HACE
  • HACE or HAPE occurs in approximately 1 to 2% of people going to high altitudes
  • HAPE and HACE may occur alone, or together
  • HAPE is roughly twice as common as HACE
  • HAPE causes many more deaths than HACE
  • HAPE may appear without any preceding symptoms of AMS
  • HAPE is more likely to occur in people with colds or chest infections
  • HAPE often comes on after the second night spent at a higher altitude
  • HAPE can develop even after descending from a higher altitude
  • HACE usually develops after symptoms of AMS have appeared and often gets rapidly worse during the night.
  • HACE may develop in the later stages of HAPE.
  • HACE (High Altitude Cerebral Edema)
  • Symptoms of HACE are caused by an accumulation of fluid in or around the brain. Typically symptoms and signs of AMS become worse as HACE develops. Someone with HAPE may also develop HACE

Symptoms and Signs

  • Severe headache, which often feels worse on lying down and is not relieved by ibuprofen, paracetamol, or aspirin
  • Tiredness, severe fatigue
  • Nausea and or vomiting which may be severe and persistent
  • Loss of coordination, clumsiness. The victim needs help with simple tasks such as tying their shoelaces or packing their bag. They cannot do the finger-nose test
  • Staggering, falling. They cannot do the heel-to-toe walking test or the standing test
  • Blurred or double vision, seeing haloes around objects
  • Loss of mental abilities such as memory. They cannot do a simple mental arithmetic test
  • Confusion, hallucinations
  • Change in behavior (aggression, apathy, etc.)
  • Drowsiness, difficulty waking up, coma, death
  • Tests for HACE

Heel-to-Toe Walking Test

The victim is asked to take 10 very small steps, placing the heel of one foot to the toes of the other foot as they go. Reasonably flat ground is necessary and the victim should not be helped.

Standing test: The victim stands with eyes closed, feet together, and arms by their sides

Finger-nose test: With eyes closed, the victim repeatedly and rapidly alternates between touching the tip of their nose with an index finger and then extending this arm to point into the distance (this is a useful test if the victim is in a sleeping bag).

Mental arithmetic test: Give the victim a mental arithmetic test, eg. subtract 7 from 100, 7 from 93, and so on (but remember some people may be poor at arithmetic, even at sea level).
If the victim cannot do any of the above tests easily (or refuses to cooperate), or show excess wobbling or falling over in the two first tests (be prepared to catch the victim if they fall over!), assume they are suffering from HACE. If in doubt about the victim's performance, compare it with a healthy individual. Be prepared to keep repeating these tests.


Descend immediately (prompt descent will begin to reverse the symptoms). Descend as low as possible; at least 1000m /3280 ft. Descend even at night or in bad weather if necessary. Carry the victim if possible, as the exertion of walking can make the illness worse. If descent is not immediately possible (eg. dangerous terrain or weather, not enough helpers, or while waiting for a helicopter), oxygen or the use of a PAC and appropriate medications will keep the person alive until descent can be undertaken,

Give oxygen

  • From a bottle using a mask (2 to 4 L/min), OR
  • By using a pressure bag (this is roughly the equivalent of 2 to 4 L of oxygen/min)
  • NB: If both oxygen and a pressure bag are available, give the oxygen while the bag is being prepared and after the victim comes out of the bag.
  • Do not give oxygen inside the bag unless it is designed for this purpose and you have been trained to do so.

Give Medications:

  • 1. 8 mg of dexamethasone at once (by mouth, IV, or IM) followed by 4 mg every 6 hours
  • Dexamethasone takes several hours to work
  • Stop it once below 2500m/8200ft AND after at least 3 days of treatment by tailing off the dose slowly (give the last 3 doses every 12 hours)
  • Diamox, 250 mg every 8 to 12 hours
  • Treat persistent vomiting with anti-emetic (anti-vomiting) medication
  • Prop the victim up in a semi-reclining position as lying down flat may make their condition worse
  • Avoid even the slightest exertion if this is possible
  • Even walking a few steps may make their symptoms worse or reappear
  • Do not leave the victim alone
  • If a person is turning blue or is falling into unconsciousness, give them rescue breathing before they stop breathing
  • HAPE (High Altitude Pulmonary Edema)
  • Symptoms of HAPE are due to the accumulation of fluid in or around the lungs
  • It may appear on its own without any preceding symptoms of AMS (this happens in about 50% of cases), or it may develop at the same time as AMS
  • HAPE can easily be mistaken for a chest infection or asthma: if in doubt treat for both

Symptoms and Signs

A reduction in physical performance (tiredness, severe fatigue) and a dry cough are often the earliest signs that HAPE is developing Breathlessness. In the early stages of HAPE, this may mean just taking a bit longer to get one breath back on resting after mild exercise. Later on, there is a marked breathlessness with mild exercise. Finally, breathlessness occurs at rest. Record the respiratory rate (NB: At 6000m (19700ft), the acclimatized respiration rate is up to 20 breaths per minute). The dry cough may later become wet with frothy sputum, which may be bloodstained (pink or rust-colored). This is a serious sign.

Wet sounds in the lungs when breathing in deeply (place your ear on the bare skin of the victim's back below the shoulder blades; compare with a healthy person). Note: There may be NO wet sounds in even quite severe HAPE: this is called dry HAPE. There may be mild fever up to 38.5ºC a sense of inner cold, and pains in the chest. Blueness or darkness of face, lips, tongue, or nails due to lack of oxygen in the blood (cyanosis). Drowsiness, difficulty waking up, coma, death.


Same general treatment as for HACE, EXCEPT: Using oxygen or a PAC (Portable Altitude Chamber) and appropriate medications will keep the person alive until descent can be undertaken.

Give medications: Nifedipine. This should only be used if bottled oxygen or a pressure chamber is not available and the victim is warm and well-hydrated. Give the modified release (MR) form of the tablets (20 mg every 12 hours for 2 or 3 days). If a fall in blood pressure occurs due to nifedipine (pallor, weak rapid pulse, dizziness on standing), treat it as a shock. Diamox 250 mg every 8 to 12 hours. An asthma reliever spray (2 puffs every 4 hours) may help.