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Altitude Illness

Any of several illnesses associated with higher-than-usual altitudes. Illnesses are of several types, including:

• Acute Mountain Sickness (AMS).
• High Altitude Pulmonary Edema (HAPE).
• High Altitude Cerebral Edema (HACE).
• High Altitude Retinal Hemorrhage (HARH).
• Subacute and Chronic Mountain Sickness (CMS).

This illness is a complication that represents failure to recover from AMS over a long period of time.

These illnesses affect most body systems, especially the brain, heart, lungs, gastrointestinal tract, circulatory system and electrolytes.

• Other altitude-related problems include frostbite, blood clots in the legs and lungs, dehydration, swollen feet and ankles.
• Pre-existing illnesses that are aggravated by high altitude include sickle-cell disease or trait, chronic heart disease or chronic lung disease.

Causes

Insufficient oxygen at high altitudes. Following are the altitudes at which each type of illness can occur:

• AMS: 7,000 to 8,000 feet or higher.
• HAPE: 9,000 to 10,000 feet.
• HACE: 10,000 to 12,000 feet.
• HARH: 17,000 feet.

Additional factors that contribute to development of altitude illness include:

• Fatigue or overwork.
• Previous episodes of altitude illness.
• Chronic illness of any sort, particularly cardiovascular and lung diseases.
• Obesity.
• Age over 60.
• Excess alcohol consumption.
• Use of mind-altering drugs, including narcotics and tranquillizers.

Signs and symptoms

• AMS: Headache, nausea, vomiting, shortness of breath, sleep disturbances.
• HAPE: Shortness of breath, cough, weakness, headache, coma.
• HACE: Severe headache, staggering gait, hallucinations, stupor. These indicate swelling of the brain. Death will occur without descent.
• HARH: Visual disturbances, including spots before the eyes. Blood clots and bleeding into the retina occur in 50% of those who go above 17,000 feet.
• CMS: Shortness of breath, fatigue, bloated face and body, congestive heart failure after years of living at high altitude (rare).

Recognize Altitude Illness

If you have recently ascended to 8000 feet or more, you may notice a headache as the first warning sign of altitude illness. Other symptoms may follow and include:

• Loss of appetite, nausea, or vomiting
• Fatigue or weakness

Diagnosis

• Your own observation of symptoms.
• Medical history and exam by a doctor.
• Laboratory studies such as EKG and chest x-ray.

Treatment

Oxygen - Lack of oxygen at altitude is the chief reason why people suffer from altitude sickness, so breathing supplemental oxygen is obviously going to make a difference. But oxygen is a hard commodity to come by in the mountains - cylinders of oxygen are not easily portable. When oxygen available in AMS settings, it should be used.

• AMS: Descend to lower altitude if illness lasts 2 or more days.
• HAPE: Oxygen, rest and diuretics help, but rapid descent is usually necessary.
• HACE: Oxygen and corticosteroids help, but rapid descent to lower altitudes is the only certain way to recover.
• HARH: No treatment except to descend.
• CMS: Return to lower altitudes if symptoms persist.

Medication

Your doctor may prescribe:

• For AMS: Diamox (carbonic anhydrase inhibitor).
• For HAPE: Oxygen, furosemide (diuretic), morphine (narcotic pain reliever).
• For HACE: Corticosteroids.

Prevention

• Don't ascend to heights that cause symptoms. If you must climb, become acclimatized gradually by a slow ascent.