Altitude sickness may develop in those who ascend rapidly to altitudes greater than 2500m (8100ft). In Bolivia this includes La Paz (altitude 4000m). The risk increases with faster ascents, higher altitudes and greater exertion.
Symptoms may include headache, nausea, vomiting, dizziness, malaise, insomnia and loss of appetite. Severe cases may be complicated by fluid in the lungs (high-altitude pulmonary edema) or swelling of the brain (high-altitude cerebral edema).
Being physically fit offers no protection.
Those who have experienced altitude sickness in the past are prone to future episodes.
The best treatment for altitude sickness is descent. If you are exhibiting symptoms, do not ascend. If symptoms are severe or persistent, descend immediately.
To protect yourself against altitude sickness, take 125mg or 250mg acetazolamide (Diamox) twice or three times daily, starting 24 hours before ascent and continuing for 48 hours after arrival at altitude. Possible side effects include increased urinary volume, numbness, tingling, nausea, drowsiness, myopia and temporary impotence. Acetazolamide should not be given to pregnant women or anyone with a history of sulfa allergy.
For those who cannot tolerate acetazolamide, the next best option is 4mg dexamethasone taken four times daily, best with medical supervision. Unlike acetazolamide, dexamethasone must be tapered gradually on arrival at altitude if taken for longer than 10 days, since there is a risk that altitude sickness will occur as the dosage is reduced. Dexamethasone is a steroid, so it should not be given to diabetics or anyone for whom steroids are contraindicated. A natural alternative is gingko, which helps some people.
When traveling to high altitudes, it’s also important to avoid overexertion, eat light meals and abstain from alcohol.
If your symptoms are more than mild or don’t resolve promptly, see a doctor immediately. Altitude sickness should be taken seriously; it can be life-threatening.