Acute Mountain Sickness (AMS) can develop at any altitude over 2,000 meters.
The early symptoms are headache, extreme fatigue, and loss of appetite. Some
people become breathless at rest. AMS is the result of fluid accumulating in
parts of the body. Where it does not belong: in the brain, in the lungs or
both. When mild symptoms develop, it is a signal that you must stay at that
altitude until symptoms have gone away. Never ascend with any symptoms of AMS!
Usually within one or two days you will feel well and can continue your trek.
If you are resting at the same altitude and your symptoms are becoming worse,
then it is necessary to descend. Worsening symptoms of AMS include increasing
tiredness, severe headache, vomiting and loss of coordination. There are signs
of High Altitude Cerebral Edema of HACE. HACE can lead to unconsciousness and
death within 12 hours if progressive symptoms are ignored. Increasing shortness
of breath, cough and tiredness are signs of High Altitude Pulmonary Edema or
HAPE. HAPE can also be rapidly fatal if ignored.
Prevention of Altitude Illness:
- Having a sensible itinerary
is the most important way to avoid altitude illness. It is recommended to
climb not more than 1,000ft (300m) a day above an altitude of 10,000 ft
(3,000m). If the terrain is such that this is not possible, one need to
have two rest days e.g. 2 rest days are recommended at Namche Bazaar where
2,000ft (600m) are gained in 1 day from Phakding for most itineraries.
Having flexibility with 1-2 extra days built into your schedule will allow
you to rest when you are not feeling well and help avoid altitude illness.
It also helps to `climb high` and `sleep low`.
- Use Diamox-which blocks an
enzyme in the kidney and makes the blood acidic which is interpreted by
the brain as a signal to breathe more. Diamox therefore, enhances the
physiological response to altitude by increasing the rate and depth of
breathing and it also acts as a mild diuretic. Side effects of the drug
are: tingling of fingers and toes and tingling around the mouth. Sulfa
allergic individuals are recommended not to take this drug. Prophylactic
dose of Diamox is half or one 250mg tablet twice a day. Use of Diamox will
not mask the symptoms of altitude illness if it is to occur. Start taking
Diamox the day before ascent to 10,000 ft (3,000m), continue it through
your ascent to higher altitudes and stop when you start descending.
- Other preventive strategy
such as Gingko Biloba which was once thought to be useful for altitude
illness prevention has not been found useful in several studies.
Salmeterol (Serevent) inhaler used to treat asthma can help prevent HAPE
and may be used by HAPE susceptible people prophylactic ally. For persons
allergic to sulfa drugs and for abrupt ascents, it is possible to use
dexamethasone, a very potent steroid drug.
Treatment of Altitude Illness:
For mild symptoms, one can stay at the same altitude to see if symptoms will
resolve and ascend when symptoms have resolved completely. Diamox can also be
used to treat mild to moderate symptoms. If symptoms persist or worsen at this
altitude, descent is required.
For severe symptoms of HACE or HAPE, descent must begin immediately whenever
feasible. Helicopter evacuation may be essential for descent unless there is
rapid improvement with medical treatment and walking down is feasible. Physical
exertion even when it is for descent can be detrimental for patients with HAPE.
Severe HAPE patients should be carried down if helicopter evacuation is not