Acute Mountain Sickness (AMS) (HB)

Acute Mountain Sickness is the first stage that we can see as we move to higher places and can happen at altitudes as low as 6,000 feet, though most typically above 8,000 feet. Acute mountain sickness is a very mild form of High-Altitude Cerebral Edema (HACE) which we will talk about in the next section.

Basically, as a person ascends in altitude, the hypoxia from different concentrations of gasses increases the fluid shift to extra-cellular spaces. When this happens in the brain, the accompanying edema basically creates early signs of increasing intracranial pressure.

AMS is a precursor to both high-altitude cerebral edema and high-altitude pulmonary edema.

Signs and Symptoms

A patient with AMS can have headaches, feel lightheaded or dizzy, and generally complain of malaise (not feeling well). They may also complain of a little nausea, fatigue, and loss of appetite.

Prevention

You can never fully prevent AMS, but you can reduce the chance of it happening. You should stay well hydrated (even to the point of slight over-hydration—just don’t push into hyponatremia). It also helps to gradually acclimatize to an area—even a few days of low effort or rest at a close altitude will help. Being fit and healthy also help greatly.

There are a few prescription medications that you can take that will help, but the best way is via being fit, acclimatized, and hydrated.

Treatment

Descend to a lower altitude. If you can tolerate NSAIDs, you can take a low dose to help with symptoms, but only to help get to lower altitude—not to continue working. Also, the patient should catch up on hydration.