If the climber is able to walk, then it is almost always possible to treat altitude sickness by descending. Sometimes a person may need to be assisted by guides and porters if they are unable to descend by themselves. In either case, descending is always the best solution.
The only exception to this rule is when climbers are staying at Crater Camp. Here, climbers need to ascend higher before they can descend, which is difficult with AMS, especially overnight. In this case, only, a hyperbaric chamber is the best way to treat AMS as immediate descent may not be possible.
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