DISORDERS CAUSED BY ALTITUDE - Medicine for Mountaineering and Other Wilderness Activities - page 354

• Coma and death
HIGH-ALTITUDE PULMONARY EDEMA (HAPE)
• Increasing shortness of breath, particularly on exertion
• Dry cough later producing pink sputum
• Extreme fatigue progressing to unconsciousness
HIGH-ALTITUDE RETINAL HEMORRHAGES (HARH)
• Rarely cause symptoms except when in macula
• Macular hemorrhage causes central blind spot
• Visible only with an ophthalmoscope
• Most resolve in ten to twenty days
PERIPHERAL EDEMA (also caused by exercise at low altitude)
• Painless swelling of face, ankles, and hands
• Scanty dark yellow urine
• Subsides with passage of more urine
OTHER HIGH-ALTITUDE CONDITIONS
High-Altitude Retinal Hemorrhage
Hemorrhage into the retina (the layer of sensitive light receptors in the eye) is common
above 14,000 feet (4300 m). The incidence increases with altitude but is rare below 12,000
feet (3600 m). Usually the hemorrhages are small and cause no symptoms, but rarely the
bleeding involves the macula (the area of most acute central vision) and can cause blurred
vision or even a tiny area of blindness.
The hemorrhages are painless and usually can be detected only by looking at the retina
with an ophthalmoscope. Occasionally the hemorrhages are larger,involve more ofthe ret-
ina, and cause blurring or loss of vision in portions of the visual field for that eye.
No evidence of a relationship between hemorrhages and other forms of altitude illness
hasbeenfound.Thehemorrhagesdonotappearidenticaltoretinalhemorrhagesassociated
with conditions suchasdiabetes orhypertension at sea level. The exudates that often occur
in these conditions are extremely rare with high-altitude hemorrhages.
Most hemorrhages disappear in a week or two, even at altitude, but bleeding into the
macula can leave small central blind spots that persist for many years. Persons who have
hemorrhages on one climb are neither more nor less likely to have them again. Because a
blind spot can persist after a macular hemorrhage, some specialists advise individuals with
such defects not to go to high altitude again.