Understanding Acute Mountain Sickness (AMS)

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What Is High Altitude of Contents

High altitude is like the VIP section of Earth’s atmosphere, where the air gets a bit thin and the scenery is breathtaking – literally. When we talk about high altitude, we’re referring to areas above sea level where the air pressure is lower compared to lower altitudes.

As you ascend to higher altitudes, there’s less atmospheric pressure, which means there’s less oxygen available for you to breathe. This can lead to a decrease in the oxygen saturation in your blood, and that’s where things get interesting, or challenging, depending on how you look at it.

Given enough time to adapt, most people can adjust to altitudes between 5000m (Everest Base Camp) and 5500m.Going up too fast and you risk suffering from altitude related illness.

 

Acute Mountain Sickness

AMS is the most common form of altitude sickness. It often occurs around 2500m or higher but can occur at lower altitudes.

 

Symptoms Of AMS

  • Headache
  • Nausea
  • Vomiting
  • Fatigue
  • Poor Appetite
  • Dizziness
  • Sleep Disturbance

 

Before You Go at High Altitude

  • Learn about the symptoms of AMS
  • If you plan to use Diamox – learn all about side effects and try one at home to find out how you feel.
  • Check you are not allergic to Diamox
  • If you plan to use Diamox – learn all about side effects and try one at home under someone’s supervision to find out how you feel.

 

Diamox

The drug acetazolamide can be used reduce the effects of AMS and as a prevention from AMS. It works by speeding up acclimatization, but does not mast the symptoms of AMS, HAPE and HACE while taking it.

Some people are allergic to Diamox. There are side effects, e.g., tingling, especially of hands but it’s not harmful and will go away when you stop taking it. It makes you pee ever more.

 

High Altitude Cerebral Oedema (HACE)

HACE is related to severe AMS. HACE is believed to be caused by swelling in the brain and can kill very quickly if not treated.

 

Symptoms Of HACE

  • Severe headache
  • Become clumsy
  • Act differently-unhelpful, violent, lazy
  • May have bad, non-stop vomiting
  • See, hear, feel, smell odd things
  • Confused
  • Reduced consciousness

 

Check For

  • Touch nose with index finger with eyes closed?
  • Walk heel to toe in straight line?
  • Stand upright, with eyes shut and arms folded?
  • Do Simple maths?

If not able to do or have difficulty doing any of the above, suspect HACE. HACE can develop very quickly with no other problems.

 

What to do:

Stay with the person at all times – do not leave them on their own.

Descend now – not later or in the morning.

Sit them upright and keep warm

Give oxygen if you have it.

Give dexamethasone if you have it.

Give diamox if you have it.

If really unable to descend – prolonged use of a pressure bag may be needed.

 

High Altitude Pulmonary Oedema (HAPE)

HAPE results from an accumulation of fluid that comes from the blood and leaks into the oxygen-exchanging air sacs of the lungs. It is exacerbated by cold, exercise and dehydration.

 

Symptoms Of HAPE

  • Trouble breathing
  • Tired and weary
  • Coughing
  • Froth and later blood in spit
  • Lips, tongue and nails become blue

HAPE can develop in 1-2 hours or over several days and even when descending.

 

Check For

  • Has there been recent ascent?
  • Does it take long time to get breadth after exercise?
  • Are they breathless when resting?
  • Is the breathing rate increasing?
  • Can wet/crackling sound be heard in chest

 

What to do:

  • Stay with the person all times – do not leave them on their own.
  • Descend now – not later or in the morning.
  • Sit them upright and keep warm
  • Give oxygen if you have it.
  • Give nifedipine if you have it.
  • Give diamox if you have it.
  • If really unable to descend – prolonged use of a pressure bag may be needed.

 

In serious cases death can occur within as little as an hour of symptoms being noticed.

 

Three important rules to avoid altitude sickness (from Shlim and Gallie 1992).

  • Learn the early symptoms of altitude illness and be willing to recognize when you –and others-have them.
  • Never ascend to sleep at a higher altitude with any symptoms of altitude sickness. Anyone with symptoms of altitude illness who ascends will get worse.
  • Descend if your symptoms are getting worse while resting at the same altitude.

 

 

About the author

Gurdit Singh

Gurdit Singh has been leading treks in the Himalayas for the last 8 years. He has lead more than 100 trek batches in India and Nepal. He loves taking people into mountains and help them connect with nature. Before coming into adventure field, he was working in Accenture as a software consultant. Besides trekking he loves playing tennis and cycling. He has cycled from Chandigarh to Kanyakumari covering almost 3500km. He has done his Basic and Advance Mountaineering Courses and he is qualified Trip Leader and Wilderness First Responder from NOLS.