Altitude Illness

shutterstock_163362512Much of this information comes from Peter Hackett, MD, a wilderness medicine expert on mountaineering and altitude related illness and treatment.

Altitude illness is usually due to the stress of decreased oxygenation in the setting of an individual who is not acclimatized.  It can happen at any altitude over 8,000 feet and usually occurs during the initial ascent.

Two areas of the body that are most affected by altitude illness are the brain and the lungs.  When altitude illness strikes the brain it is divided into two groups called Acute Mountain Sickness (AMS) and High Altitude Cerebral Edema (HACE).  Lung injury is usually due to lung edema called High Altitude Pulmonary Edema (HAPE).

Risk factors for altitude illness:

1)   Genetic susceptibility

2)   Live at an altitude of less than 3000 feet

3)   Fast rate of climb/ascent

4)   Past history of high altitude illness (HAI)

5)   Age less than 50 years old (for Acute Mountain Sickness – AMS)

6)   Heavy exertion/exercise

7)   Pre-existing illness (especially for High Altitude Pulmonary Edema – HAPE)

Acute Mountain Sickness (AMS): Diagnostic Criteria

1)   Recent gain in altitude

2)   Headache and any of the following

  1. Gastrointestinal upset
  2. Fatigue or weakness
  3. Dizziness or lightheadedness
  4. Difficulty sleeping

3)   Feels like a hangover

Treatment of Acute Mountain Sickness:  Usually gets better on it’s own.  Average duration of symptoms is about 16 hours.  It may persist for weeks at higher altitudes however.  There may be progression to High Altitude Cerebral Edema (HACE) with or without High Altitude Pulmonary Edema (HAPE).  It responds well to descent/treatment.

1)   Oxygen therapy

2)   Descent

3)   Hyperbarics

4)   Acetazolamide (Diamox) – 125 to 250mg every 8-12 hours – start taking the day before travel until day 2 or 3 at altitude.

5)   Hyperventilation

6)   Dexamethasone 4mg every 6 hours – careful because this can lead to adrenal failure if used at high doses and if it’s not tapered gradually.

7)   Treat symptoms of headache with ibuprofen/naproxen, codeine, etc. and nausea with Zofran or Phenergan

Acetazolamide Prophylaxis:  125-250mg twice a day (5mg/kg/day) starting the day before travel and continued until day 2 or 3 at altitude.  If allergic to sulfonamides (sulfa) be cautious.  Side effects of the medication are dose related.  More commonly a feeling of numbness/tingling, metallic taste in the mouth, generalized fatigue, nausea and blurry vision can occur.

Prevention of altitude sickness:

1)   Go up slowly in staging – avoid a sea level to 9,000 foot climb in one day

2)   Sleep at a max of 2000 feet higher elevation each night

3)   Acclimatize to 10-12,000 feet before going any higher

High Altitude Pulmonary Edema (HAPE):  Symptoms

Early:  Fatigue, weakness, dry cough, shortness of breath with activity.  May progress to increased respiratory rate, increased heart rate.

Late:  Pink or blood-tinged sputum from lungs, crackles heard with stethoscope in the right axilla/arm pit.

Treatment for HAPE:  Oxygenation is the highest priority.  Descend with minimal exertion.  For mild/moderate cases use bed rest with oxygen.  For severe illness use high flow oxygen with descent and perhaps a hyperbaric bag.  There is some thought about using pulmonary vasodilators such as calcium channel blockers, nitric oxide, Viagra and/or Dexamethasone.

Preparation:  Take a medical kit with Diamox and dexamethasone and albuterol inhalers.  If you’re with medical providers, you may have access to nifedipine or Viagra also which may be helpful.

For more information:

1)   www.altitudemedicine.org

2)   www.hypoxia.net

3)   Auerbach’s Wilderness Medicine

4)   DuPoint Travel Medicine

5)   Tintinelli Emergency Medicine

If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medicine society:  http://www.wms.org/

This document is for informational purposes only.  Please consult your medical provider before attempting high altitude travel.

 

I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

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