What is the treatment and prevention for altitude sickness?

Treatment and Prevention of Altitude Sickness

The most effective treatment for altitude sickness is immediate descent to lower altitude, while prevention is best achieved through slow ascent (less than 400m/day when above 2,500m) and prophylactic acetazolamide (125mg twice daily starting 24 hours before ascent). 1

Understanding Altitude Sickness

Altitude sickness, also known as acute mountain sickness (AMS), occurs when individuals ascend rapidly to high altitudes where the partial pressure of oxygen is reduced. It encompasses three main conditions:

1. Acute Mountain Sickness (AMS) - Mild to moderate symptoms including headache, nausea, fatigue, dizziness, and poor sleep
2. High-Altitude Cerebral Edema (HACE) - Severe form of AMS with severe headache, ataxia, and mental deterioration
3. High-Altitude Pulmonary Edema (HAPE) - Life-threatening condition with fluid accumulation in the lungs

Risk Factors

• Prior history of altitude sickness
• Low home elevation
• Poor physical conditioning
• Rapid ascent
• Higher maximum and sleeping altitudes
• Intense exercise upon arrival at altitude 1

Prevention Strategies

Non-Pharmacological Prevention

• Slow, gradual ascent - The most effective prevention method:
  • Limit ascent to less than 400m/day when above 2,500m
  • Include a rest day for every 600-1200m gained 1
• Proper hydration - Maintain adequate fluid intake
• Avoid alcohol - Can worsen dehydration and symptoms
• Moderate activity - Avoid strenuous exercise upon arrival

Pharmacological Prevention

1. Acetazolamide (first-line):

   • Dosage: 125mg twice daily starting 24 hours before ascent
   • Higher doses (500-750mg/day) may be more effective for rapid ascents above 3,500m 1
   • Mechanism: Improves gas exchange, increases arterial oxygen levels, and reduces symptoms 2, 3

2. Dexamethasone (alternative):

   • Dosage: 4mg four times daily
   • Limitation: Should be used only for short-term prevention (2-3 days) due to side effects 1, 4
   • Particularly useful when acetazolamide is contraindicated

Treatment Approaches

Mild to Moderate AMS

1. Stop ascent and rest
2. Acetazolamide: 250mg twice daily or 500mg slow-release once daily 4
3. Supplemental oxygen if available
4. Descend if symptoms worsen

Severe AMS and HACE

1. Immediate descent - Most critical intervention
2. Supplemental oxygen
3. Dexamethasone - For cerebral edema
4. Hyperbaric therapy (portable hyperbaric chamber) if descent is impossible

HAPE Treatment

1. Immediate descent - Primary treatment
2. Supplemental oxygen
3. Nifedipine - 20mg three times daily when descent is impossible 1
   • Mechanism: Reduces pulmonary hypertension 5
4. Minimize exertion - Rest and limit physical activity

Special Considerations

• Cardiovascular conditions: Patients with heart conditions should consult physicians before high-altitude travel

  • NYHA class I-II heart failure patients can travel to high altitudes if stable
  • NYHA class IV heart failure patients should avoid high altitude travel 1

• Women: May have different responses to altitude

  • Consider timing altitude exposure during the luteal phase of the menstrual cycle
  • May need greater reduction in training intensity during altitude exposure 1

Common Pitfalls to Avoid

• Ignoring early symptoms - Early recognition and treatment are crucial
• Continuing ascent despite symptoms - Can lead to life-threatening conditions
• Inadequate acclimatization time - Rushing ascent is the most common cause of altitude sickness
• Overreliance on medications - Drugs help but don't replace proper acclimatization
• Dehydration - Can worsen symptoms and complicate recovery

Remember that both HACE and HAPE are life-threatening conditions requiring aggressive treatment. The key to successful management is early recognition, supplemental oxygen administration, and descent when necessary 3.