ACUTE MOUNTAIN SICKNESS
Mountain sickness is a cluster of symptoms (not a
disease) consisting of some combination of headache,
nausea, anorexia, fatigue, dizziness, shortness of breath
and insomnia. Caused by a lack of oxygen when one ascends
at too rapid a pace, it usually occurs above 8,000 feet
(2,438.3 meters). The range of symptoms making up mountain
sickness shares many clinical features but can be divided
into three syndromes:
- Acute mountain sickness (AMS) - usually
a benign condition with symptoms as noted above. Usually
relieved by a short descent or slowing down the rate
of ascent.
- High altitude cerebral edema (HACE) - usually
occurs only at very high altitudes. Symptoms include
headaches, confusion, hallucinations, poor judgment.
This condition requires immediate treatment consisting
of descent and supplemental oxygen; dexamethasone
may be prescribed.
- High altitude pulmonary edema (HAPE) - symptoms
include rapid onset of breathing, nocturnal shortness
of breath, chest pain, confusion, headache, cough
(which may be bloody). This condition requires immediate
treatment consisting of descent and supplemental oxygen.
Anyone ill at high altitudes with any of the symptoms
noted above should be assumed to have some variety of
mountain sickness. This implies the treatment will include
standard medication protocols, descent and consideration
of evacuation. It's difficult to predict whom AMS, will
affect, as susceptibility varies among individuals.
A previous episode does not always indicate the occurrence
of future episodes. Men and women appear to be affected
equally and younger people are more adversely affected
than older people. Good aerobic conditioning does not
seem to confer a protective effect. Of course, it's
always preferable to be in good physical condition prior
to strenuous trekking. Travelers with conditions such
as pulmonary hypertension, sickle cell disease or symptomatic
cardiovascular disease should not travel to high altitudes
(i.e., over 8,000 feet; 2,438.3 meters).
If you have a particular medical problem, or potential
problems, you may need special counseling and preparation.
The major concern may not be the altitude, but rather
the remoteness of the journey where medical care may
not be available.
The rate of ascent recommended by most authorities
- 984.3 feet (300 meters) a day for two days when climbing
above 9,843 feet (3,000 meters), slowing down to just
492.2 feet (150 meters) per day thereafter - is too
slow for enthusiastic climbers and is seldom heeded.
Other preventive recommendations for climbers include:
(1) eat a high-carbohydrate diet that is low in salt
and fat, (2) drink extra water because increased respiration
and drier air at high altitudes causes dehydration,
(3) try to sleep at a lower elevation than the height
of your climb that day, (4) stay warm, dry and avoid
overexertion, (5) avoid cigarettes and alcohol, (6)
apply sunscreens and lip balm liberally, (7) wear sunglasses
for protection against sun rays that are much stronger
than at sea level, (8) take aspirin or alternative medication
for altitude headaches (9) talk to your health care
provider about the use of Diamox® as a preventive medication.
Treatment consists of: (1) early recognition, (2) descent
(the only safe management), (3) supplemental oxygen,
(4) lightweight, pressurized, portable, inflatable bag
(such as the Gamow bag from DuPont) and (5) medications
(See below).
Options for medications include:
- Diamox® (acetazolamide) 125 mg., 250 mg
and 500 mg sequels. This is the first drug of choice
for prevention of mountain sickness.
- Decadron® (dexamethasone) 4 mg. Use only
for treatment, not prevention, except in unusual situations.
- Nifedipine 20 mg. Use every six hours for
pulmonary edema when descent is not possible. Should
not be used routinely.
Based
on CDC,
Health Information for International Travel 2000-2001,
DHHS, Atlanta, GA, 2001;
and Dr. Richard Thompson's book
Well on the Road - A
Practical Guide for the International Traveler, 2002.
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