From the Guidelines
Altitude sickness symptoms typically include headache, nausea, dizziness, fatigue, as identified by the Lake Louise Scoring system, which is a recommended self-assessment questionnaire for systematic screening of Acute Mountain Sickness (AMS) 1. These symptoms usually begin within 6-24 hours of ascending to high altitude. The Lake Louise Scoring system rates the severity of headache, nausea, dizziness, and fatigue, with scores ranging from 0 (no discomfort) to 3 (severe symptoms) 1. The symptoms occur because the body is exposed to lower oxygen levels at high altitudes, causing hypoxia in tissues. People may also experience shortness of breath, difficulty sleeping, and other symptoms. If you experience these symptoms while at altitude, the best immediate treatment is to descend to a lower elevation. Medications like acetazolamide (Diamox) can help prevent or treat symptoms by accelerating acclimatization, while ibuprofen or acetaminophen can help with headaches. Staying hydrated and avoiding alcohol are also important preventive measures. Some key factors to consider when assessing altitude sickness include:
- The Lake Louise Scoring system criteria: headache, nausea, dizziness, and fatigue 1
- The importance of slow ascent (< 400 m/day) to reduce the risk of AMS 1
- The potential benefits of long pre-acclimatisation (about 2 weeks with > 8 h/day at progressively increasing altitudes) for those who have access to altitude/hypoxic facilities 1
From the Research
Signs and Symptoms of Acute Altitude Sickness
The signs and symptoms of acute altitude sickness can vary in severity and may include:
- Headache, which can range from mild to severe 2, 3, 4, 5, 6
- Loss of appetite 3, 4, 6
- Nausea and vomiting 3, 4, 6
- Dizziness and insomnia 3
- Apathy 4
- Reduced appetite 4
- Peripheral oedemas and fluid retention 4
- Ataxia (loss of movement coordination) 2, 3, 5
- Mental deterioration ending in coma (in severe cases of high altitude cerebral edema) 3
- Incapacitating fatigue, chest tightness, dyspnoe at minimal effort, and orthopnoe (in cases of high altitude pulmonary edema) 3
- Dry non-productive cough that progresses to cough with pink frothy sputum due to hemoptysis (in cases of high altitude pulmonary edema) 3
- Stress dyspnea, coughing, and rasping breathing noises (in cases of high altitude pulmonary edema) 5
Severity of Symptoms
The severity of symptoms can range from mild to severe, and may be classified as:
- Mild to moderate acute mountain sickness, characterized by mild to moderate headache, loss of appetite, nausea, and dizziness 3
- Severe acute mountain sickness, characterized by severe headache, ataxia, and mental deterioration 3
- High altitude cerebral edema, characterized by severe headache, ataxia, and mental deterioration ending in coma 3
- High altitude pulmonary edema, characterized by incapacitating fatigue, chest tightness, dyspnoe, and orthopnoe 3