What is the treatment and prevention for altitude sickness?

Altitude Sickness Prevention and Treatment

The most effective strategy for preventing altitude sickness is slow ascent (<400 m/day above 2,500m), while acetazolamide is the primary pharmacological preventive measure, and immediate descent is the definitive treatment for severe cases. 1

Types of Altitude Illness

Altitude illness encompasses three main conditions:

1. Acute Mountain Sickness (AMS) - Most common form, characterized by:

   • Headache
   • Poor appetite and nausea
   • Fatigue and weakness
   • Dizziness or light-headedness
   • Poor sleep

2. High-Altitude Cerebral Edema (HACE) - Severe progression of AMS:

   • Severe headache unresponsive to acetaminophen
   • Loss of coordination
   • Ataxia
   • Mental deterioration progressing to coma

3. High-Altitude Pulmonary Edema (HAPE) - Life-threatening condition:

   • Extreme fatigue
   • Chest tightness
   • Progressive dyspnea (from exertion to rest)
   • Dry cough progressing to pink frothy sputum

Prevention Strategies

Non-Pharmacological Prevention

• Gradual ascent: Keep rate <400m/day above 2,500m 1
• Rest days: Include one rest day for every 600-1200m gained 1
• Minimize physical activity before acclimatization 1
• Maintain proper hydration 1
• Pre-acclimatization: When possible, spend 2+ weeks with >8h/day at progressively increasing altitudes 1

Pharmacological Prevention

For those with history of altitude illness or when rapid ascent is unavoidable:

• Acetazolamide: 250 mg twice daily or 500 mg slow-release once daily, started before and continued during ascent 2
• For HAPE-susceptible individuals: Nifedipine started with ascent and continued 3-4 days after arrival at terminal altitude 3
• Alternative options:
  • PDE5 inhibitors (sildenafil, tadalafil) 3, 1
  • Dexamethasone (4 mg, 4 times daily) for short-term prevention only (≤2-3 days) 3, 2

Treatment Approaches

Acute Mountain Sickness (AMS)

• Stop ascent and rest
• Acetazolamide 500 mg/day 4
• Descend if symptoms worsen

High-Altitude Cerebral Edema (HACE)

• Immediate descent (minimum 300m) 1
• Supplemental oxygen to maintain SpO₂ >90% 1
• Dexamethasone for cerebral symptoms 4

High-Altitude Pulmonary Edema (HAPE)

• Immediate descent is mandatory 3, 1
• Supplemental oxygen 3
• Nifedipine if descent is impossible or delayed 3, 4

Special Considerations

Children

• Children are susceptible to HAPE with symptoms including cough, exertional dyspnea, and reduced exercise performance 3
• Prevention and treatment principles are similar to adults 1

Pre-existing Conditions

• Patients with good exercise tolerance (NYHA class I-II) can generally travel to intermediate altitudes (~2,000m) 1
• NYHA class III patients should consider supplemental oxygen during air travel 1
• NYHA class IV patients should avoid high altitude travel 1
• Patients with congenital heart disease may have increased pulmonary vascular resistance at altitude 3, 1

Common Pitfalls and Caveats

• Underestimating risk: Even physically fit individuals can develop altitude illness
• Continuing ascent despite symptoms: This can lead to progression to more severe forms
• Inadequate preparation: Failing to allow time for acclimatization
• Relying solely on medications: Drugs should supplement, not replace, proper acclimatization
• Misdiagnosis: Symptoms may mimic other conditions; rapid improvement with oxygen suggests altitude illness 3
• Inappropriate use of dexamethasone: Should not be used for more than 2-3 days due to side effects 2
• Air travel after eye surgery: Not recommended for 2-6 weeks post intraocular gas instillation 3

Remember that altitude illness can affect anyone, regardless of age, gender, or physical fitness. The key to prevention is slow ascent, and the definitive treatment for severe cases is immediate descent.