High Altitude Illness
Update Date：2024/07/05，
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According to the 2018 Lake Louise Consensus on the diagnosis of acute mountain sickness (AMS) at altitudes above 2500 meters, evaluation is based on four symptoms: headache, dizziness, poor appetite/nausea/vomiting, and fatigue/weakness. Each symptom is scored from 0 to 3 based on severity, with headache requiring at least 1 point. A total score of at least 3 points is necessary to diagnose AMS. Severe headache scoring 3 points alone can also diagnose AMS. Scores of 3-5 indicate mild AMS, 6-9 moderate AMS, and 10-12 severe AMS.
Prompt recognition of AMS symptoms is crucial as severe cases can progress rapidly, potentially leading to life-threatening conditions like high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). Early treatment involves:
1. Descending to lower altitudes (descending by at least 1,000 meters for HAPE and HACE).
2. Adjusting the environment (providing oxygen, increasing ambient pressure—recommendation for HAPE and HACE includes using a pressure bag).
3. Administering oxygen (maintaining blood oxygen saturation >90%).
4. Resting (reducing oxygen consumption).
5. Medications: Recommended drugs include acetazolamide (Diamox), dexamethasone (steroid), nifedipine (calcium channel blocker), and medications like Cialis or Viagra as per CDC Travel Health Yellow Book and Wilderness Medical Society guidelines.
The U.S. CDC Yellow Book for Travelers' Health emphasizes preventive measures against high altitude illnesses, noting that severe altitude sickness typically develops slowly and predictably. They assert that with appropriate precautions, such as acclimatization strategies, deaths from high altitude illnesses are avoidable unless hindered by weather or geographical barriers.
Key tips for adapting to high altitude environments include:
1. Gradual ascent (avoiding sleeping at altitudes above 2750 meters in a single day).
2. Consider using acetazolamide (Diamox).
3. Limiting strenuous activity during the first 48 hours at high altitudes.
4. Avoiding alcohol during the initial 48 hours at high altitudes. Rapid ascent to altitudes above 2800 meters in a day is considered high risk for developing altitude sickness (e.g., in areas like Hehuanshan and Yushan). It is recommended to use acetazolamide prophylactically 24 hours before ascending, or consider staying overnight at 1500-2500 meters (e.g., Qingjing Farm, Wuling Farm) to acclimate gradually and enhance adaptation to altitude.
Dr. Hsu, Chia-Ching from the Emergency Medicine Department