Prevent and prepare

• Check how to access local emergency services and pack appropriate signals and contact details when going to high altitudes.
• Ensure you have the right equipment with you to make a safe descent.
• Eat high-energy foods and drink high-calorie drinks, as well as water, to prevent dehydration.
• Ensure someone knows the route you plan to take if you are venturing to a remote place, and when you expect to return.
• Avoid alcohol.

Early recognition

People may start to experience symptoms around 2400 m (roughly 8000 feet). Twenty-five per cent of travellers experience AMS above 3500m (11,483 feet), with 50 per cent experiencing it above 6000m (19,685 feet). Be aware of the signs of altitude sickness if travelling above this altitude (Hackett & Shlim, 2019).

Several altitude sickness diagnostic-scoring systems exist. The Lake Louise Criteria for Altitude Sickness (Roach et al., 2018) are as follows:

Acute mountain sickness

If the person chooses to remain at a certain altitude, AMS may improve with rest, hydration and medication. However, the symptoms will improve faster by descending to a lower altitude. There is also the risk that AMS will progress to HAPE or HACE.

• Headache and at least one of the following symptoms: fatigue or weakness; dizziness or light-headedness; gastrointestinal symptoms (nausea or vomiting, loss of appetite); difficulty sleeping; shortness of breath.

High-altitude pulmonary oedema

HAPE is when fluid collects in the lungs (pulmonary oedema) and causes extreme shortness of breath. It is life-threatening and requires immediate, safe descent.

• At least two of the following symptoms: difficulty breathing while resting; coughing; weakness or decreased physical performance; chest tightness or congestion and;
• At least two of the following signs: crackling or wheezing heard in one or both lungs when breathing; bluish colouring to the skin, lips and fingers; rapid breathing and elevated heart rate.

High-altitude cerebral oedema

HACE is when fluid collects on the brain, causing confusion, coma, and if untreated, death. It is life-threatening and requires immediate, safe descent.

• Change in responsiveness, behaviour, normal movement or coordination in a person either with or without acute mountain sickness.

First aid steps

1. Help the person move to a lower altitude as quickly and safely as possible. Encourage them to drink water.
2. If the person has prescribed medication for altitude sickness, help them take it.
3. Have the person rest at a lower altitude until their symptoms resolve. If local regulations permit, and you are trained to do so, administer oxygen to the person. You may do this upon arrival at a lower altitude, or if necessary while descending with the person.
4. Access EMS if the person’s condition doesn’t improve.

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NOTE

Monitor the person’s temperature to ensure they do not get too cold or too hot. See Hypothermia or Hyperthermia.

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Access Help

• Access help if the person is unable to descend on their own and it is unsafe for other group members to transport them to a lower altitude. Help may take many forms, including other hikers, search and rescue, formal evacuation teams or military assistance.
• Access EMS if the person’s condition does not improve.

Recovery

• If a person with AMS is asymptomatic, they may continue to ascend. They should monitor themselves for signs and symptoms of AMS, HAPE and HACE.
• Once descended to a lower altitude, a person with HAPE or HACE should not re-ascend until their symptoms have resolved and they have been examined by a medical professional.

Context considerations

• Altitude sickness can affect a variety of groups ranging from hikers, climbers, seasonal employees and tourists. There are many towns and cities across the world that are at a high altitude. We advise first aid programme developers to work with local authorities and tour companies to publicly display educational material informing people of the signs and symptoms, the importance of staying hydrated and how to get help.
• Refer to local guidelines and include any context-specific information in the programme.
• Engage local medical experts, mountain rescue groups and tour operators when developing content for this topic.
• Follow local laws and regulations concerning helping people with prescribed medications and administering oxygen.
• Use posters and other media in high altitude areas with tourists to raise their awareness of altitude sickness.

Facilitation tips

• Emphasise how to prevent and recognise the symptoms of altitude sicknesses as often, the person affected may not realise they have it.
• Use visual materials (pictures and videos) to illustrate signs and symptoms of the different types of illness that high altitudes can incur.

Learning connections

• Being at high altitudes can cause someone to Feel faint; make connections to this topic.
• Symptoms of AMS may appear similar to those of Dehydration.