Table 1.

Management and prevention of high altitude illness

Iclinical presentation	Management	Prevention
Mild acute mountain sickness Headahce with nausea, dizziness and fatigue during first 12 hrs after ascent to high altitude (> 3000 m)	Descend 500 m or more, rest and acclimatize; or speed acclimatization with acetazolamide (125-250 mg BD); or treat symptoms with analgesics and antiemetics	Ascend at a slow rate; spend a night at an intermediate altitude; avoid overexertion; avoid direct transport to an altitude of more than 3000 m; consider taking acetazolamide (125-250 mg BD) beginning on day before ascent and continuing for 2 days at high altitude
Moderate acute mountain sickness Moderate to severe headache with marked nausea, dizziness, lassitude, insomnia, and fluid retention at high-altitude lasting for 12 hrs or more.	Descend 500m or more; if descent is not possible, use a hyperbaric chamber or administer low-flow oxygen (1-2 lts/min); if descent is not possible and oxygen is not available, administer acetazolamide (250 mg BD), or dexamethasone (4 mg PO or IM q 6 hourly), or both until symptoms resolve.	Ascend at a slow rate; spend a night at an intermediate altitude; avoid overexertion; avoid direct transport to an altitude of more than 3000m; consider taking acetazolamide (125-250 mg BD) beginning one day before ascent and continuing for 2 days at high-altitude; treat acute moutain sickness early.
High-altitude cerebral oedema Acute Mountain Sickness for 24 hrs or more, severe lassitude, mental confusion, ataxia.	Initiate immediate descent or evacuation; if descent is not possible, use a portable hyperbaric chamber; administer oxygen (2-4 lts/min;) administer dexamethasone (8 mg PO or IM or IV initially and then 4 mg q 6 hourly); administer acetazolamide if descent is delayed.	Avoid direct transport to an altitude of more than 3000m; ascend at a slow rate; avoid overexertion; consider taking acetazolamide (125-250 mg BD) beginning one day before ascent and continuing for 2 days at high-altitude; treat acute mountain sickness early.
High-altitude pulmonary oedema dyspnea at rest, moist cough, severe weakness, drowsiness, cyanosis, tachycardia, tachypnea rales.	Administer oxygen (4-6 lts/min until condition improves, and then 2-4 lts/min to conserve supplies); descend as soon as possible, with minimal exertion, or use a portable hyperbaric chamber; if descent is not possible or oxygen is not available, administer nifedipine (10 mg PO initially and then 30 mg of extended release formulations PO q 12-24 hrs); add dexamethasone if neurological deterioration occurs.	Ascend at a slow, graded rate; avoid overexertion; people with earlier episode should avoid high altitude areas.

m – meters, PO – per orally, IM – Intra muscular, IV – Intra venous, BD -twice daily, lts – liters, q – each quantity, mg – milligrams, hrs – hours