Chronic Mountain Sickness


Epidemiology

General Comments

  • Chronic Mountain Sickness Occurs in High-Altitude Dwellers

Incidence

  • Incidence of Chronic Mountain Sickness in Andean Countries: 5-15% of the population residing >3200m (10,500 ft)
    • Chronic Mountain Sickness Affects Approximately 2 Million People

Physiology

Chronic High Altitude-Related Disease (see High Altitude)

Diagnosis

Complete Blood Count (CBC) (see Complete Blood Count)

  • Polycythemia
    • Hemoglobin >21 g/dL or Hematocrit >63%

Arterial Blood Gas (ABG) (see Arterial Blood Gas)

Clinical Manifestations

Cardiovascular Manifestations

Right-Sided Congestive Heart Failure (CHF) (see Congestive Heart Failure)

  • Epidemiology
    • May Occur

Gastrointestinal Manifestations

Digestive Complaints

  • Epidemiology
    • XXXX

Hematologic Manifestations

Polycythemia (see Polycythemia)

  • Epidemiology
    • XXXXXX
  • Physiology
    • XXXXXX
  • Diagnosis
    • Complete Blood Count (CBC) (see Complete Blood Count)
      • Polycythemia is Defined as a Hemoglobin >21 g/dL or Hematocrit >63%

Neurologic Manifestations

Depression (see Depression)

  • Epidemiology
    • XXXX

Fatigue (see Fatigue)

  • Epidemiology
    • XXXX

Headache (see Headache)

  • Epidemiology
    • XXXX

Sleep Disturbance

  • Epidemiology
    • XXXX

Social Exclusion/Psychological Degradation

  • Epidemiology
    • XXXX

Pulmonary Manifestations

Dyspnea (see Dyspnea)

  • Physiology
    • XXXXXX

Pulmonary Hypertension (see Pulmonary Hypertension)

Respiratory Failure-Chronic Type I Hypoxemic (Hypoxemia) (see Hypoxemia and Respiratory Failure)

Respiratory Failure-Chronic Type II-Hypoxemic, Hypercapnic (see Respiratory Failure)

  • Epidemiology
    • XXXXX
  • Physiology
    • Loss of Ventilatory Acclimatization to High Altitude-Associated Hypoxia, Leading to Central Hypoventilation (High Alt Med Biol, 2016) [MEDLINE]
  • Diagnosis

Treatment

Acetazolamide (Diamox) (see Acetazolamide)

  • Rationale
    • Carbonic Anhydrase Inhibitor induces a Non-Anion Gap Metabolic Acidosis with a Secondary Increase in Ventilation, Resulting in Decreased Hypoxemia
  • Clinical Efficacy
    • Trial of Acetazolamide in Chronic Mountain Sickness in Peru (Am J Respir Crit Care Med, 2005) [MEDLINE]
      • Acetazolamide Decreases Hypoventilation
        • Acetazolamide Increased Nocturnal SaO2 (by 5%), Decreased Nocturnal Heart Rate (by 11%), and Decreased Sleep Apnea-Hypopnea Episodes (by 74%)
      • Acetazolamide Decreased Erythropoietin and Decreased Hematocrit
    • Peruvian Trial of Chronic Acetazolamide in Chronic Mountain Sickness (Am J Respir Crit Care Med, 2008) [MEDLINE]
      • Chronic Acetazolamide (250 mg/day x 3 wks) Improved Erythrocytosis
      • Chronic Acetazolamide (250 mg/day x 3 wks) Improved Hypoxemia
      • Only Patients Treated for 6 mo Had a Decrease in Pulmonary Vascular Resistance (PVR)
      • Treatment Had No Adverse Effects

Phlebotomy (see Phlebotomy)

  • Clinical Efficacy
    • Only Transiently Effective in Relieving Symptoms
      • However, Phlebotomy Undesirably Decreases the Oxygen Content in Distal Tissues, Worsening Symptoms Over Time

Supplemental Oxygen (see Oxygen)

  • Clinical Efficacy
    • May Acutely Improve Symptoms
      • However, Supplemental Oxygen is Expensive, May Not Be Available in High-Altitude Communities, and is Not the Best Long-Term Treatment

Relocation to Sea Level

References