Mountain sickness develops when the body is unable to adapt to an abrupt increase in altitude. Atmospheric pressure declines with increasing altitude; though the percentage of oxygen in the air remains constant, less oxygen enters the bloodstream through the lungs. To compensate, the heart and lungs work harder and the body gives off more carbon dioxide, which can upset its biochemical balance and cause fluid to accumulate between cells.
Symptoms include headache, fatigue, nausea, rapid heartbeat, and breathlessness. This illness is most common among people who travel to high altitudes without allowing time for their bodies to adjust. Typically, a person will fly to a high destination and set out to ski, sightseeing, or engage in other strenuous activities, attributing tiredness, headache, insomnia, and other symptoms to jet lag. Exertion worsens the problem and can lead to buildup of fluid in the brain or lungs. The latter is signaled by breathlessness that persists even during rest, a cough that may produce frothy, blood tinged sputum, and blueness of the lips. Indications of cerebral edema include an unsteady or drunken gait, eye hemorrhages, headache, drowsiness, and coma. Some 20 to 25 percent of people who travel from a low altitude to mild mountain sickness. Other persons develop symptoms at only 6,500 feet; children, women who are premenstrual, and people over age 40 seem to be the most vulnerable.
Other Causes of Altitude Problems
Persons with pulmonary hypertension or congestive heart failure are especially susceptible to mountain sickness. Some who live at high altitudes develop chronic mountain sickness, or Mange’s disease, marked by shortness of breath, fatigue, and clotting problems. Blood letting may help, but recovery usually requires descending to sea level.
Diagnostic Studies And Procedures
Mountain sickness and its complications can usually be diagnosed on the basis of symptoms. When pulmonary or cerebral edema are suspected, blood and spinal fluid analyses may be ordered to rule out pneumonia and other disorders.
Simple mountain sickness does not require medical treatment, although it might be a good idea to return to a lower altitude. Bed rest and extra fluids are also advisable. Acetazolamide (Diamox), a medication with a diuretic effect, may be prescribed to speed recovery and help prevent pulmonary edema. Aspirin also helps alleviate headache and may reduce the risk of lung clots as well. Pulmonary and cerebral edema are emergencies that call for immediate descent. If this is not possible, the best procedure is to take the person to a high altitude first aid center where there is equipment to raise air pressure to simulate that of a lower altitude. Diuretics may be administered, but care must be taken to avoid dehydration. Sometimes, administering intravenous steroids helps to lessen cerebral edema.
When traveling to a high altitude, increase your intake of water to replace the fluid lost during rapid breathing of dry air. Reduce salt intake, and abstain from caffeine, which can worsen sleep disturbances, and alcohol, which exacerbates the sickness. Eat frequent, small meals that are low in fat and high in easily digested carbohydrates, such as fruits and starches.
To prevent mountain sickness, ascend gradually-no more than 2,000 feet a day at elevations of 5,000 to 10,000 feet, and 1,000 feet a day at greater heights. Plan to spend each night at an elevation of 8,000 feet or lower until your body is fully acclimatized. Rest frequently, and limit vigorous activity such as skiing, hiking, or climbing to a half day for the first two or three days. Should you develop mild symptoms, balancing frequent rests with moderate activity will help your body adjust more quickly than taking to your bed. If you want to speed acclimatization, talk to your doctor about a prescriptior for Diamox. Studies show that starting this drug two days before arriving at a high altitude may prevent mountain sickness. Carefully follow directions for its use; abruptly stopping the drug can lead to pulmonary or cerebral edema. Some Himalayan climbers take the steroid dexamethasone (Decadron) to prevent cerebral edema, but its long term use is discouraged because of its many possible side effects bleeding problems, lowered immunity, muscle weakness, and ulcers, among others.