Acute Mountain Sickness, HAPE & HACE: Causes, Symptoms, Treatment, Prevention

Q - Why is it important to know about Acute Mountain Sickness or Altitude Sickness?
A - It is a crucial issue that no high altitude trekker can afford to ignore because it can be fatal/deadly, and it is better to have some information about what can happen to you on 8000+ feet, and ignorance is not bliss.

Q - What is Acute Mountain Sickness? And how different it is from Altitude Sickness? How bad can it get?
A - Altitude sickness is a broader term, AMS is the first form of altitude sickness, this can develop further into more complicated sickness which is called HACE or HAPE which is High Altitude Cerebral Edema and High Altitude Pulmonary Edema.
And how severe it can get? You can die. So it can get very critical, and it can get critical very quickly like in a couple of hours.


Q - Causes of AMS?
A - When we climb to high altitude, especially 8000ft or 2500 metre and above, the oxygen available is less than what our body needs. Now when you have less oxygen, especially when you are making physical effort, your body is not able to manage with the shortage of oxygen. So your body gives you a signal to halt and get comfortable to the less availability of oxygen and then climb forward, and to do that, our body gives us a signal which is called altitude sickness.

Q - What are the symptoms of AMS? What are the first symptoms that you see?
A - There are many symptoms of AMS, and most people are, of course, very familiar with headaches but are not familiar with the other symptoms. Usually combined with the headache you will feel the nauseatic, uneasy feeling in your stomach, vomiting like feeling, lightheadedness or dizziness, you feel extremely weak and fatigued; these are the very common symptoms of Altitude Sickness.
It doesn't hit you the moment you reach high altitude, but it can take time like 3-4 hours. A lot of people thinks that they will get altitude sickness only if they have a headache; it's wrong because all these symptoms may come even without a headache. So people might ascribe those things to something else like if they are feeling uneasiness, they think it is happening because of the food they had earlier.
But in the Mountains, remember only one Golden rule, i.e. if you are feeling suspicious or uneasy, attribute it to Altitude sickness first and start eliminating it rather than treating a symptom such as uncomfortable feeling with a Digene or Eno.
Your body is giving you a signal that it has not been able to digest food, and you must examine why. Its because it has not got the amount of oxygen for it to able to combust the food that is in our stomach.

Q - Acute Mountain Sickness is prone to hit trekkers going in groups and big organisations, is that true?
A - It is true, AMS is more likely to hit you if you are going on a trek in a group. But the reason behind it is more of a psychological than the surrounding factors.
When you are travelling in an organised group, there is a speed of the group that you have to keep up with. Because of that, there is this constant pressure that you are trying to keep up with the speed of the group, a lot of people don't disclose that they are suffering from something, it can be little late.
People who have done high altitude treks, they are prone to Altitude sickness. Not because they don't know what happens, but it is that they have this tremendous peer pressure not to talk about it because they are the ones who have been instrumental in getting their friends together on the trek. Now he thinks that   ''If I say that there something wrong with me, then my friends might imagine that I'm an @ss! I'd rather not do that'', and then he doesn't disclose anything.
In simple words, the experience of trekking has got nothing to do with altitude sickness. If you haven't done an 8000+ trek in the last 12-15 days, you are very much likely to get hit by altitude sickness.

Q - Are you more prone to Acute Mountain Sickness when you are trekking in the Indian Himalayas or Nepal as compared to the Alps(Mountain range in Europe)?
A - Yes because in the Indian and Nepali Himalayas, it is the design of the mountains and we climb very quickly. Day 1 you are in the foothills, day 2 you are at 9-10000 feet and day 3 you are at 13-14000 feet. Now there is no place to camp in between, and when you are climbing so rapidly, you are prone to altitude sickness because you don't get a chance in the Himalayas to acclimatise.

Q - How do you deal with AMS when it hits? How do you treat it?
A - The first thing that you have got to keep in mind is that the moment you feel uneasy with anything you need to alert your buddies around you or your Trek Leader because he/she can be wiser in dealing with it or will at least be able to get help if required. Denial has more deaths than altitude sickness.
So about the treatment, if you feel uneasy, mostly it will be a headache with other symptoms like nauseatic, vomit like feel, weakness etc. Start the Triple One Test, which means take one tablet of Disprin, one litre of water and rest for an hour. And if your uneasiness disappears than it was the simple case of a headache but if it is still there then surely you got hit by AMS.

Q - Any other Medication?
A - It depends on at what altitude you get hit by the AMS. If you are at 10-11000 feet, it is easy to descend to 7-8000 feet in a couple of hours where there is no oxygen problem, But if you are at 14-15000 feet and you are 2-3 days away from the nearest help, then things can become little problematic.
You can carry a couple of medication, i.e. Diamox (Acetazolamide) and Dexamethasone (Dex). Diamox helps you to acclimatise faster by taking the bicarbonate out of your body through your urine. It acidifies your blood, and then body hyperventilate(taking more breath/oxygen).
Diamox usually take 2-4 hours to work on the symptoms. If the symptoms are gone, you can finish your trek but if the symptoms are still there and you know they are going to increase and not decrease then take Dexamethasone and descend immediately because now the situation out of your hand. This drug will buy you time to descend after that situation, and after reaching the desired altitude, you are going to be okay.

Q - How to prevent AMS before going for a trek?
A - There are two ways: 
Natural - Before going on a trek like 2-3 days before start drink enough water to hydrate yourself and before starting the trek, acclimatise yourself for a day at the base camp and hope for the best.
Medication(Not harmful) - Take a preventive course of Diamox to acclimatise faster. It is simple, 24 hours before starting your trek start taking a half tablet or 125mg of Diamox every 12 hours until you finish the trek. Diamox reduces the chances of getting altitude sickness by 80%. And even after this preventive course, if you get hit by the AMS, start taking the whole tablet of it. 

Q - Is it wise to go back if you have descended and feel better?
A - Yes, if you have descended to 7-8000 feet and you have taken a day rest, then you can go for the summit because now you are better acclimatised.

Q - Fit people think that their probability of getting AMS is much lower. Is that true that if you are fit, you less likely to be hit by AMS?
A - Unfortunately no, this is a misconception which a lot of people have. You need to be fit to do a trek, but being fit has got nothing to do with altitude sickness. Whether you are fit or unfit, you are equally likely to get altitude sickness, and it doesn't reduce your chances.
But the more fit trekkers can be more prone to AMS, and this is something which surprise people that's because the more fit trekkers are generally faster and because of that they are spending less time in a particular altitude so their chances of getting AMS increases.  

Q - So what about age? Does that have anything to do with AMS? If you are older, you more likely to be hit by AMS?
A - No, it is just a myth.

HAPE & HACE

HAPE and HACE are the advanced stages of the Acute Mountain Sickness, and it doesn't mean they will always hit you after AMS or will accompany AMS, but they can occur by themselves too.

Q - What is HAPE? 
When oxygen is less in the air, the blood vessels around your lungs start constricting and increases the blood pressure, and because of this water enters into your lungs. It is a fatal condition, and if left untreated, you can die.
Symptoms - Weakness, tiredness, breathlessness, coughing

Q - What is HACE?
It happens when fluids accumulate inside the brains.
Symptoms - Severe headache, Nauseatic, Vomit, Illogical behaviour

Q - Prevention and Treatment?
A - Prevention is the same as AMS, and the treatment in all the altitude sickness is to descend. But if you can not descend right away or it hits you in the night, take Diamox and Nifedipine (decreases the blood pressure) in case of HAPE and Dexamethasone in case of HACE. Now, it doesn't mean that these medications will treat you, but they will give you time so that you can descend after some time. 

Note - Don't go on a high altitude trek unprepared, and before going on a trek, consult your physician for the medication purpose.

Source - Different trekking organisations, the experience of trekkers with over 15 years of trekking, medical organisations, and basic knowledge of air pressure and physics.

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