Going to High altitude? You are at Risk because
- You leave the comforts of your daily livings
- Different climatic conditions
- Your previous medical history might act as a predisposing factor
Acute Mountain Sickness (AMS)
- It is a syndrome complex of (a) Headache (b) nausea (c) dizziness (d) sleeplessness and (e) fatigue. Of these, headache is the cardinal symptom.
- Nobody is immune to AMS above 2000-2500m.
- It is not related to physical fitness or gender
- Early AMS feels exactly like alcohol hangover. It is also heralded by the feeling of deep inner chill or a sense of being well.
- Late or advanced AMS denotes increase in severity of the above mentioned symptoms
- A typical picture will be: a porter arrives at a high altitude carrying a heavy load. Immediately, he goes in a corner of a dark room and rest there covered with a blanket from head to toe. He does not want any tea or snacks. He starts to throw up once in a while. When asked, he says he has the worst headache as if somebody is hammering a nail into his forehead and he feels terrible. He is still huddled in the corner at dinner time. When friends bring him food, he does not even want to look at it. When asked, he says yes, I want to go down.
- If not interfered with you, AMS could progress to two fatal complications: (a) High altitude cerebral edema (HACE) meaning swelling of the brain or water in the brain, (b) High altitude pulmonary edema (HAPE) meaning water in the lungs.
It is characterized by increasing headache and vomiting, staggering gait, altered consciousness and other neurological signs. It is thought to be the progression of AMS. The condition develops more rapidly in the night in someone with AMS, probably because of further decrease in ventilation during the night. This explains the common belief in our people that somebody with a bad headache should not go to sleep. This is true but what is equally important is that they should not remain in the same place either. This fact highlights the importance of keeping a high index of suspicion and making decisions about descent in the day and not waiting for the night or the next morning. This single most important test to detect HACE in somebody with AMS is the tandem gait test where a person walks straight on a line in a hill to toe fashion. If he falls beyond the line, it is strongly suggestive of HACE. The person becomes comatose soon thereafter. It is invariably fatal unless interfered with.
It is characterized by increasing breathlessness even at rest, productive cough and bluish discoloration of lip and tongue. The sputum may become blood tinged later on. It usually strikes the second night onwards. The bluish discoloration as a late sign and should not happen in the hands of good friends. One important thing about HAPE is that it can occur in a setting outside of AMS. People can have full blown HAPE without headache and other symptoms of AMS. Thus when confronted with the above signs and symptoms of HAPE, those should not be ignored or dismissed in the light of absence of headache. HAPE likewise seems to be a completely different pathology. It is invariably fatal unless interfered with
Why does it (AMS) happen?
- All is because of low atmospheric pressure.
- Low atmospheric pressure leads to low oxygen tension in the air which we inhale and causes a series of changes in the body which may lead to AMS. There is leakage of fluid from the blood stream into the brain. The arteries of the lungs also constrict causing increase in pressure in them which promotes fluid leakage into the lungs. These occur when out body foes not get sufficient time to adapt to the change in pressure. Some people may be unable to adapt at all because of some abnormalities in their bodies, i.e. absence of one pulmonary artery, the relative proportion of their brain and the skull etc.
What are the risk factors for AMS?
- Rapid ascent is the main risk factor
- Dehydration, airways infections, overexertion, sleeping pills, obesity and alcohol are other risk factors.
- Previous history of altitude sickness is the best predictor of whether one would be struck again
- Non flexible itineraries, peer pressure, tough and stoic personality are some other risk factors
- Excess chill and cold exposure is a known risk factor for HAPE
So what do we do?
- AMS is preventable and treatable
- Our body is a machine. It always gives signs when it is malfunctioning. All we need to do it to listen to our body and help, not hinder its process.
- Avoid the risk factors
- By slow ascent, we can digest the altitude, the process is called acclimatization. Here, our body gets sufficient time to adjust to the high altitude. It is prudent to take a rest every third day with the rate of ascent not more than 400m per day after the altitude of 3000m. Climb high and sleep low is another of the dictums of altitude medicine. Moderate exertion on rest days is also recommended.
- People acclimatizing well will have increased dieresis which helps prevent fluid accumulating in the body.
- The process of acclimatization can be accelerated by the use of a drug called acetazolamide (Diamox) taken at a dose of 250mg twice daily (5mg.kg for kids)
How do I know whether I have AMS?
- All ailments in the height are altitude sickness unless proved otherwise. The tendency to rationalize and attribute the initial symptoms of altitude sickness to something else must be avoided and discouraged.
- There is a ‘Self-assessment and scoring systems’ to help you know where you are with altitude sickness. It is called the Lake Louis scoring system. It is advisable that all use this to score oneself once in the morning and once in late afternoon. In this, out of total 15 points, a score of 3 or more with headache plus any other symptoms denotes AMS. The severity is classified as:
3 to 6 Mid-AMS
7 to 9 Moderate AMS
10 or more than 10 Severe AMS
What is the treatment of AMS?
- The million dollar saying is ‘go down, go down, go down’
- There is no magic altitude which you should descend. Go down to the place where you were comfortable before. This is usually about 300m or more.
- Stay where you are and do not ascend if you have moderate AMS.
- If one is badly struck, we could only ‘buy time’ for him/her to go down by the use of (a) injectable or oral steroid (dexamethasone at the dose of 4 to 8 mg 6 hourly) (b) oxygen (c) diamox (d) pressure bag (Gamow bag) and (d) diuretic (drug which makes one pee).
- Nifedipine, a drug used commonly in hypertension could be used in setting of HAPE at the does of 10mg three to four times per day.
- Diamox should be avoided in people who are allergic to sulfa drugs. The most common side effect is tingling of the hands and feet and the eyes and the lip. Some might experience that the aerated drinks taste flat. People may wake up several times in the night because of the diuretic effect.