What is altitude sickness?

Altitude sickness

Altitude or mountain sickness, is a condition which affects not just mountaineers and skiers but anyone who travels to altitudes above 3,500m (11,500 ft). Rarely, altitude sickness leads to two potentially fatal conditions – High Altitude Pulmonary Oedema and High Altitude Cerebral Oedema – both of which are medical emergencies.

What causes altitude sickness?

The lower level of oxygen available at high elevations causes altitude sickness. Reduced oxygen in the blood, along with other changes in blood chemistry affects the nervous system, muscles, heart and lungs.

What are the symptoms?

* Altitude/Mountain Sickness – symptoms usually appear within a few hours of ascent and may include one or many of the following:
- headache
- insomnia
- irritability
- dizziness
- muscle aches
- fatigue
- loss of appetite
- nausea or vomiting
- swelling of the face, hands and feet

* High Altitude Pulmonary Oedema – is a build-up of fluid in the lungs leading to:
- breathlessness
- cough
- extreme fatigue
- severe headache

* High Altitude Cerebral Oedema – can be thought of as worsening of altitude sickness symptoms with the addition of:
- confusion
- extreme fatigue
- hallucinations
- lack of co-ordination
- severe headache
- vomiting
- seizures
- eventual coma and death

What can be done about it?

It is important to note that in most cases, altitude sickness is mild and short -lived. Limit your activity level and refrain from further ascent for a day or two until all symptoms disappear. Aspirin or ibuprofen can be used for headache and drugs used for travel sickness such as Avomine (promethazine), Stemetil (prochlorperazine) and Stugeron (cinnarizine) may help the nausea and sickness. Oxygen by mask also helps the symptoms. If symptoms become worse during a day of rest, it is very important to descend until you begin to improve.

In serious cases, those affected must be brought down from the mountain and taken to a hospital as quickly as possible. The administration of pure oxygen can help. In hospital, diuretic drugs are often given to help reduce oedema.

The condition of patients with high altitude pulmonary oedema often improves rapidly after descending a few hundred metres. Patients with cerebral oedema may take days or weeks in hospital to recover.

What can you do to help yourself?

The same advice that applies to climbers applies to everyone at a high altitude:
* Above 3,500m the speed of further height gain should be gradual. The British Mountaineering Council advises taking a week above 3,500m before sleeping at 5,000m
* Watch for signs of altitude illness
* Drink extra water
* Don’t do too much too fast
* Avoid alcohol
* Avoid sleeping pills, tranquillisers and narcotic-based pain relievers.

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