Course Material
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Factors Affecting Development of Altitude Illness

Several medical problems can occur when ascending to high altitude. The problems range from uncomfortable symptoms to life threatening conditions. The occurrence of these problems varies with the following:

  • Rate of ascent: the faster you climb the greater your risk.
  • Altitude attained (especially sleeping altitude): the higher you sleep the greater the risk.
  • Length of exposure: the longer you stay higher the greater the risk.
  • Level of exertion: hard exertion without rest increases the risk.
  • Hydration and diet: dehydration, and high fat and high protein diets increase the risk.
  • Inherent physiological susceptibility: some people are more likely to become ill; the reason is unknown.
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Acute Mountain Sickness (AMS)—Symptoms and Treatment

Possibly due to hypoxia (lack of oxygen). Symptoms occur 12-24 hours after ascent, decrease around the third day, and range from mild to moderate/severe.

Mild Symptoms Treatment
  • Feels like a “hangover”
  • Headache
  • Fatigue
  • Shortness of breath
  • Nausea
  • Lack of appetite Lightheadedness/dizziness
  • Trouble sleeping (Cheyne-Stokes respiration)
  • Stop ascent (if possible)
  • Rest
  • Analgesics for headache
  • Medications for nausea
  • Hydration and nutrition
  • Low flow oxygen
  • Acetazolamide (Diamox)
  • Do not ascend until symptoms go away

Moderate/Severe Symptoms Treatment
  • Headache not relieved by analgesics
  • Loss of muscular coordination (cannot walk a straight line)
  • Decrease in mental status
  • Vomiting
  • Symptoms worsen or do not subside
  • Descend immediately (if possible)
  • Gamow bag
  • Dexamethasone (Decadron)

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High Altitude Cerebral Edema (HACE)—Symptoms and Treatment

Results from swelling of the brain due to fluid leakage. Symptoms generally occur after 5 to 7 days at high altitude.

This is a serious illness that could lead to death if unrecognized and untreated.

NOTE: The diagnosis of severe AMS versus HACE is difficult. Always assume the worst.

Symptoms Treatment
  • Severe headache
  • Loss of coordination
  • Decreased mental status (lethargy, confusion)
  • Weakness
  • Vomiting
  • Coma
  • Descend immediately (if possible)
  • Oxygen
  • Gamow bag
  • Dexamethasone (Decadron)

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High Altitude Pulmonary Edema (HAPE)—Symptoms and Treatment

Results from fluid leakage into the lungs. Oxygen transfer from the lungs to the blood is impaired. HAPE is not caused by heart failure or pneumonia.

This is a severe illness that could lead to death if unrecognized and untreated.

Symptoms Treatment
  • Shortness of breath at rest
  • Bluish color to the skin
  • Productive cough with frothy pink-tinged fluid
  • “Tight chest”
  • Fatigue/weakness
  • Gurgling/crackling noise heard in the chest during breathing (often called Rales)
  • Increased heart/respiratory rate
  • Mental changes (confusion)
  • Dry persistent cough
  • Descend (if possible)
  • Oxygen
  • Prop up patient
  • Gamow bag
  • Nifedipine (Procardia or Adalat)