An Increasing number of people are now travelling to greater heights as it is becoming more readily accessible and cheaper to do so. However there can be adverse medical implications from doing so. Altitude sickness can affect people that ascend to more than 2500 metres of altitude, whether by climbing or being transported to these heights. It can also affect a person if they ascend too quickly for the body to adapt. It can present with mild symptoms that can subside when the individual has rested or returned to a lower altitude. However more extreme symptoms can be life-threatening if not counter-acted or treated.
Altitude sickness occurs because as you ascend to higher altitudes the air pressure reduces. The air still contains the same proportion of oxygen but as the air is thinner at higher altitudes there are fewer oxygen molecules available in each breath. This means that you have to breathe deeper and faster to obtain the same amount of oxygen that your body requires. If you ascend at a slow rate your body has a chance to acclimatise and adapt to the changing conditions. Your breathing rate will slow down as your body makes more red blood cells to carry more oxygen in your blood.
The most important initial treatment for someone displaying signs of altitude sickness is to stop the ascent and rest to allow the body to acclimatise. If symptoms persist then drop to a lower altitude. Normal symptoms illustrated by the body whilst it is acclimatising can be an increased breathing rate, deeper breathing, shortness of breath on exercise, changes to breathing patterns during sleep, disturbed sleep or passing more urine than normal.
If the affects of altitude are more severe than this then the body can display symptoms of the following three problems; acute mountain sickness, high-altitude cerebral oedema or high-altitude pulmonary oedema.
The exact cause of acute mountain sickness (AMS) is not known but it is thought to be a response of the brain to lower oxygen levels in the blood at higher altitudes which produces some swelling of the brain.
High-altitude cerebral oedema (HACE) usually develops in someone who already has acute mountain sickness (AMS). The swelling of the brain that has led to AMS gets worse and starts to interfere with the function of the brain. So, HACE is really a severe form of AMS.
High-altitude pulmonary oedema (HAPE) is a build-up of fluid within the lungs. The exact reasons why HAPE can develop are unknown. It is thought that the high altitude causes an increase in pressure in the blood vessels around the lungs which leads to smaller blood vessels becoming ‘leaky’, allowing fluid to escape from the blood vessels into the lungs.
The most important treatment if you start to develop symptoms of mild AMS is to stop your ascent and to rest at the same altitude. For most people, symptoms will improve within 24-48 hours with no specific treatment. Adapting to conditions (acclimatisation) usually occurs after 1 to 3 days at a given altitude. Simple painkillers and anti-sickness medication can help headache and sickness. You should also make sure that you drink plenty of fluids.
However, if your symptoms are severe, they do not improve after 24 hours, or they are getting worse, you need to descend to a lower altitude. You also need to descend urgently if you develop any symptoms or signs of HACE or HAPE.
Treatment of HACE and HAPE is similar and most importantly it is to move down to a lower altitude immediately. If this does not happen, or is delayed, death can occur. Treatment with oxygen and medicine can help to relieve symptoms and can mean that getting someone down to a lower altitude becomes easier. However, these treatments do not remove the need for descent. The descent should be at least to the last altitude at which the person woke up feeling well. A device has been developed called a portable hyperbaric chamber. It is, essentially, an airtight bag that is pressurised by a pump. The person with HACE is placed inside it and it can provide the same effect as a descent. They will be breathing air equivalent to that at much lower altitude. This can be life-saving when descent is not possible and oxygen is unavailable.
You can also use oxygen (small cylinder) to avoid these problems. OxygenWorldwide has on certain occasions arranged medical oxygen for mountain climbing. (For availability on your destination check with firstname.lastname@example.org.