Travel Reference
In-Depth Information
the United States, Stemetil in many other countries) is the anti-nausea medicine usually re-
commended because it is known to be a respiratory stimulant, unlike some others.
AMSiscommonandusuallyself-limited,butitdeservesattentionbecauseitcanevolve
intoamoreseriousillness:high-altitudecerebraledema.OnceAMShasresolved,itissafe
to ascend further with caution. If dexamethasone is used, it should be discontinued for a
day or so before it is safe to ascend. If AMS causes a person to descend, reascending after
a day or two at a lower altitude free of symptoms is safe.
High-Altitude Cerebral Edema
High-altitudecerebraledema(HACE)representsthesevereendofthespectrumofacute
mountainsickness.InafewpeoplewithAMS,usuallyataltitudesabove12,000feet(3700
m), symptoms of brain edema become worse, sometimes with alarming speed. Ataxia or
staggering gait, which can be demonstrated early by having the individual try to walk a
straightlineheeltotoe,canbecomesobadthatthepersoncannotstandorgetintoatentor
sleeping bag. The afflicted person may not be able to get dressed, tie shoelaces, or handle
a knife and spoon.
Theindividualbecomesconfused,mayhavehallucinations,losesmemory,anddevelops
impaired judgment. These disabilities may rapidly worsen to bizarre behavior, coma, and
death.
In an extreme case, a person with a worsening headache, vomiting, and lassitude for
several days may retire to a tent to sleep and lapse into a coma. Companions may become
aware of the condition only when they cannot wake the person. Indeed, some individuals
may not respond even to painful stimuli. The person looks pale and blue (cyanotic) and,
if crackles can be heard in the lungs, HAPE is also present. Autopsies on individuals who
have died of HACE have disclosed swelling of the brain and the presence of bleeding.
Because HACE can kill, early diagnosis and treatment are essential. Recent arrivals at
altitude—and, occasionally, someone who has been at altitude for several days—who de-
velop confusion or ataxia combined with a persistent headache should be considered to
haveHACE.Theyshouldbegivenoxygenandtakentoaloweraltitudeimmediately.They
shouldbeaccompaniedduringdescentbecauseataxiamayprogressrapidlyandindividuals
may fall and be injured. Usually a descent of a few thousand feet brings relief if accom-
plished promptly. Leaving a person with HACE alone is risky—even at a lower altitude.
SomeindividualsappeartobeunusuallysusceptibletoHACEandotheraltitude-related
disorders and have suffered more than one episode. Once HACE has occurred, even if re-
covery is rapid at a lower altitude, it may recur. Most individuals who have had HACE
are unable to reascend for several days or longer due to difficulty walking. They would be
prudent to wait at least a week or two after complete return to normal before reascending.
Some authorities recommend against reascent for weeks to months.
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