Table 1.

Summary of clinical features and management of acute high-altitude illnessesa

IllnessEpidemiologyClinical FeaturesPreventionTreatment
AMSAffects 22 to 50% of travelers to 1850 to 4200 mHeadache plus one or more of the following: Nausea, vomiting, lethargy, poor sleep, light-headednessSlow ascent (above 2500 m, limit increases in sleeping elevation to 300 to 400 m/dStop ascending
Incidence higher at higher elevationsNormal neurologic examination and normal mental statusAvoid overexertionNonnarcotic pain relievers for headache
Onset of symptoms within 6 to 10 h of ascentAcetazolamide or dexamethasoneAntiemetics
Acetazolamide
Descend if symptoms do not improve in 1 to 2 d or worsen on appropriate treatment
May continue ascending if symptoms resolve
HACEAffects 0.1 to 1.0% of travelers to elevations above 3500 mPreexisting AMS or HAPE symptomsSlow ascentDescend until symptoms resolve
Most affected individuals have preceding AMS symptomsAtaxia, altered mental status lassitude, comaAvoid overexertionIf descent not possible, then supplemental oxygen or a portable hyperbaric chamber
Potentially fatal if not recognized and treated promptlyAcetazolamide or dexamethasoneDexamethasone; consider adding acetazolamide
HAPEAffects 0.2 to 8.0% of travelers between 2500 and 5500 m with greater incidence at higher elevations and with faster ascentMild disease: Decreased exercise performance, dry coughSlow ascentDescend until symptoms resolve; avoid overexertion on descent
Occurs within 2 to 5 d of ascentSevere disease: Dyspnea with minimal exertion or at rest; cough with pink, frothy sputum; cyanosisAvoid overexertionIf descent not possible, then supplemental oxygen or a portable hyperbaric chamber
Can occur without preceding AMSMay see concurrent signs or symptoms of AMS or HACENifedipineNifedipine (may not be necessary if supplemental oxygen available)
Potentially fatal of not recognized promptlySalmeterol can be used as adjunctive therapy but should not be used aloneMay consider sildenafil as add-on or alternative, but data on efficacy are lacking
  • a HACE, high-altitude cerebral edema.