Acute Mountain Sickness ( AMS) is the most common form of altitude illness and occurs in approximately 50% of people who travel to high altitudes such as :  Mount Everest base camp (5380m).

AMS generally occurs at altitudes above 2500m with symptoms presenting themselves within the first 8 to 24 hours after ascent to altitude.

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‍The most common symptom is a headache and this must be present for a diagnosis of AMS, followed by other symptoms including:

shortness of breath, nausea, vomiting, dizziness and fatigue.  

Risk factors associated with AMS also include: rate of ascent, elevation, hydration status, alcohol and narcotics, exertion upon arrival and individual susceptibility.

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Those who have had AMS describe this as: "feeling very much like a hangover". This illness can be defined as the negative health effects of exposure to high altitude caused by rapid exposure to low oxygen levels. Symptoms of AMS could at times subside within days.

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There are a number of practical treatments for AMS along with some medical options:

1. Descent should always be considered if the symptoms of AMS start to worsen, you should aim to descend below the altitude at which the first symptoms of AMS occurred.
2. Where possible, rest and reduce the amount of physical activity to a minimum, in some cases this could be enough to cure the symptoms of mild to moderate AMS.
3. Mild AMS, drinking fluids and taking simple analgesics such as: paracetamol or ibuprofen might in some cases cure the symptoms, however these could also mask symptoms.
4. Mild to severe AMS, drinking fluids and Acetazolamide, also known as Diamox, a dosage of 125mg by mouth twice a day, can be taken. However, this drug must not be taken by people allergic to sulphur. The side effects of this medication include tingling of lips and extremities as well as increased urine output.

‍References:

Barry, P.W. and Pollard, A.J. (2003) “Altitude illness”, British Medical Journal, 326(7395), pp.915-919.

Bezruchka, S. (2005) Altitude illness: Prevention & Treatment, Seattle: Mountaineers Books.

Luks, A.M., Auerbach, P.S., Freer, L., Grissom, C.K., Keyes, L.E., McIntosh, S.E., Rodway, G.W., Schoene, R.B., Zafren, K. and Hackett, P.H. (2019) “Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update”, Wilderness & environmental medicine, 30(4), pp.3-18.