High Altitude Pulmonary Oedema (HAPE)

Another form of severe altitude illness is High Altitude Pulmonary Oedema, or fluid in the lungs

High-altitude pulmonary edema occurs in mountain eers who ascend rapidly to heights of more than 2500 m. It is at the severe end of the spectrum of symptoms of acute mountain sickness , which include headache, insomnia, anorexia, lethargy, vomiting, oliguria, and peripheral edema. Vigorous young men are most susceptible to high-altitude pulmonary edema. Other risk factors include strenuous exercise, cold weather, and recent respiratory tract infection. Those who have had high-altitude pulmonary edema in the past are likely to have it again. The symptoms and signs are cough, tachypnea, tachycardia, orthopnea, cyanosis, rales, and frothy pink sputum. Symptoms usually begin two to four days after a rapid ascent, often during nighttime rest. Without the administration of oxygen, rest, and descent to a lower altitude, death may result. Radiographic findings are variable but usually consist of fluffy, perihilar infiltrates with sparing of the lung bases and periphery. 1

Though it often occurs with AMS, it is not felt to be related and the classic signs of AMS may be absent. Signs and symptoms of HAPE include any of the following:

- Extreme fatigue
- Breathlessness at rest
- Fast, shallow breathing
- Cough, possibly productive of frothy or pink sputum
- Gurgling or rattling breaths
- Chest tightness, fullness, or congestion
- Blue or grey lips or fingernails
- Drowsiness

HAPE usually occurs on the second night after an ascent, and is more frequent in young, fit climbers or trekkers.

PREDISPOSING FACTORS

• Altitude - risk of development of HAPE has been reported at 3350m in the Himalaya, 3660m in the Andes, and 2590m in the Rockies .
• HAPO is a disease affecting young healthy people, with young males being the most at risk.
• Many afflicted are of athletic disposition and totally free of lung and heart disease.
• The condition commonly afflicts the unacclimatized subject exposed to diminished barometric pressure who engages too quickly in strenuous physical activity on arrival .
• There is a distinct individual predisposition to the development of the condition, since some patients have repeated attacks of AMS and HAPE each time they return to the mountains after a sojourn at lower altitudes.
• Very important predisposing factor is re-exposure to hypoxia, with the lung oedema occurring in the highlander returning to his mountain home after a period spent at lower altitude.
  
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