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THE WORLD EXPEDITIONS LODGE AT Deboche in Nepal’s Khumbu region was packed. Sat down one wall were the 12 of us, five days into the High Passes trek. The seats opposite were filling fast with a boisterous party of Australian women in the last days of the same trek in reverse. All cancer survivors, they were brimming with life, talking loudly and laughing often. One of our group, a fellow Aussie, fell into the familiar Khumbu conversation: where are you headed, how long are you out? And that old chestnut – were we taking Diamox for the altitude? Heather Hawkins, leader of their group, told us they had all taken it from the start on medical advice. That stirred debate. None of our party had been told that and at that point only a couple were using Diamox, though as the days went on, others would join them. But just what is the best approach?
The effects of altitude can be dangerous, but alleviating and treating them is simple and well understood.
Most people feel some effect as altitude increases. Climbing beyond 3,000 metres, especially if moving quickly, intensifies the effects and can bring on acute mountain sickness (AMS). The first sign is usually a nagging headache, followed by fatigue, dizziness and loss of appetite. Nausea and vomiting may occur too. AMS is easily treatable and needn’t provoke alarm, assuming you are following a reasonable acclimatisation schedule. Peter Hackett is Director of the Institute for Altitude Medicine in Ridgway, Colorado. He recommends a minimum of nine days to walk from Lukla to Everest Base Camp, for instance, a schedule that allows for rest, or acclimatisation days – a chance for the body to catch up with the demands being placed on it. One way t o c h e c k h o w we l l y o u a r e acclimatising is to use an oximeter to check the oxygen saturation of your blood – not as accurate as taking a blood sample, but far easier. “Medications are not often necessary,” says Hackett, “but if desired, Diamox is the drug of choice, 125mg twice a day starting at around Namche Bazaar [3,440 metres]. Ibuprofen is another choice for prevention. For an Everest climber, meds are OK for the way in to basecamp, but before going on the mountain, they need excellent acclimatisation, without drugs.” “For persons predisposed to AMS for various reasons, or who get AMS reliably when they go to altitude, or those without adequate time for acclimatisation, Diamox started at the beginning of the trip may be a good idea.” On its website, Hong Kong’s Travel Health Service suggests simply that acetazolamide (typically marketed under the name Diamox), “. . . is taken one day before ascent and continued for several days at altitude.” The dosage they prescribe follows standard UK practice: one 250mg tablet a day. The most commonly noticed side-effects of Diamox are a mild diuretic effect and some tingling in extremities. Occasionally there are headaches and fatigue. None of these are a major concern though and allergic reactions are rare. On the other hand, AMS left untreated can escalate to far more serious high-altitude cerebral edema (HACE). “AMS can proceed to HACE,“says Hackett, “although fortunately, that is rare. AMS does not proceed to HAPE [high-altitude pulmonary edema]. Although they can occur together, AMS/ HACE and HAPE are separate – one affects the brain, the other the lungs. AMS is the common hangover feeling, without confusion or loss of balance. HACE is diagnosed on the basis of mental changes and loss of balance.” If symptoms of AMS don’t mellow with Diamox, the patient can be taken to a lower altitude, or dexamethasone – often shortened to ‘dex’ – can be administered. “Dex treats AMS very well, but does not boost acclimatisation, says Hackett. “Diamox works for AMS – not as well as dex – but it speeds acclimatisation. So if the person is not going down, the combo makes sense. The dex is stopped after a day or two, the Diamox may be continued as long as they are ascending.” The response to AMS/HACE with treatment can be dramatic – sometimes almost too dramatic. “I have had many patients who are unconscious in the Khumbu, and wake up during the flight to low altitude, and then don’t want to pay for the helicopter because they thought it wasn’t necessary!” says Hackett. “Amazing how such severe illness can reverse so quickly. With medications, the most dramatic results are with dexamethasone. I have seen cerebral edema turned around in four hours, with the patients wanting to quickly go higher! Oxygen can also result in a rapid recovery.”