Altitude sickness typically occurs in people traveling to altitudes more than 2000 meters.
- Acute mountain sickness
- High altitude cerebral edema (affecting brain)
- High altitude pulmonary edema (affecting lungs)
Why do people get it:
First of all not everyone will get high altitude sickness. For people who do get it - the symptoms can be extremely variable. Illustrated below is the body's normal oxygen pathway and adjustments of the human body at high altitude.
Normal response of the body at high altitude:
How to recognize it:
If the body is unable to adapt (more often inadequately adapt) to altitude - there is decreased oxygenation of organs which may lead to generalized weakness and dizziness and fainting.
A side effect of trying to increase oxygen delivery to organs, is an increase in pressure in the brain & lungs (see flowchart above). The increased pressure in the brain is why people get headaches, dizziness, nausea & vomiting. Increased pressure in the lungs leads to leakage of fluid in the lung tissue which further decreases the transport of oxygen from lungs to blood leading to difficulty in breathing and development of pulmonary edema.
What to do about it:
Altitude sickness can be prevented by ascending to the desired altitude slowly. As a general guideline, when above 3000 m, one should not spend subsequent nights higher than 300 m than the previous night and rest every 2-3 days. If symptoms do occur, wait for the symptoms to subside before resuming ascent.
Do not take sleeping pills or alcohol in excess. They may decrease the breathing rate and decrease oxygen content in blood (especially at night).
Medications such as acetazolamide can help in prevention but needs to be started a couple of days before the planned ascent.
If the severe symptoms develop emergency oxygen treatment may temporarily relieve symptoms but people should descend to a lower altitude. Medications such as acetazolamide, steroids (dexamethasone to decrease cerebral edema) and nifedipine (to decrease lung pressures) are helpful.
Above all - Get medical help immediately.