In Charlotte, it has been unseasonably HOT and many of us have been considering escaping to the mountains. Maybe not exactly the way these people have, but at least something to help our families cool off. This lead Dr. Cathy Wares (CMC Assistant Program Director Extraordinaire) to ponder just how children are affected by that High Altitude environment. Great question… let us take a minute to explore High Altitude Illness in Children:

High Altitude Illness: Pediatric Considerations

• Involvement of children in high altitude environments has been increasing. [Heggie, 2018; Garlick, 2017; Joy, 2015; Moraga, 2002]
  • Alpine skiing / snowboarding and extreme sports are notable.
  • Vacations/Visitation to high altitude areas.
    • Denver, Colorado is ~5,500 feet above sea level.
    • Breckenridge, Colorado is ~10,000 ft above sea level.
    • Rocky Mountains are ~10,000 ft above sea level.

• Hypobaric Hypoxia leads to the physiologic stressors associated with High Altitude Illnesses (HAI).
  • Increasing altitudes -> lower barometric pressure -> lower partial pressure of oxygen.
  • Decreased partial pressure of oxygen reduces the pressure gradient -> reduced force to drive oxygen into tissues => Hypobaric Hypoxia
  • Effects of Hypobaric Hypoxia can be seen first at altitudes of 5,000 feet.

• Children are in the group of people who are at greatest risk for environmental illness or injury.
  • The younger the child, the greater the risk. [Heggie, 2018]
  • The longer the expedition, the greater the risk of illness/injury to children present. [Heggie, 2018]
  • Other Risk Factors: [Garlick, 2017; Joy, 2015]
    • Medical conditions associated with pulmonary disease or pulmonary hypertension.
      • Down’s Syndrome, Congenital Heart Disease, Cystic Fibrosis, Sickle Cell Disease, Severe Scoliosis, Bronchopulmonary Displasia.
    • Recent upper respiratory tract infection, otitis media, bronchiolitis.
    • Children with mechanical devices that may be influenced by the atmospheric pressure changes (ex, Baclofen Pumps). [Ryan, 2018]
      

High Altitude Illness: Critical Syndromes

• ACUTE MOUNTAIN SICKNESS (AMS)
  • The most common HAI in children and adults. [Garlick, 2017]
  • Headache is the principle feature.
  • Diagnosis = Headache PLUS:
    • Insomnia, dizziness, fatigue, nausea/vomiting, or anorexia
    • In a patient who recently traveled to that altitude (usually >8,000 feet) … so not acclimatized yet.
    • In younger, non-verbal children, AMS may present with increased fussiness, decreased interaction/playfulness, decreased appetite, sleep disturbances. [Joy, 2015]
  • Prevention:
    • Best prevention is gradual ascent.
    • Acetazolamide: [Garlick, 2017]
      • Used off label in children.
      • 2.5 mg/kg/dose BID (max of 125 mg BID)
      • Has side effects (ex, metal taste in mouth, paresthesias) so often not used prophylactically.
  • Treatment:
    • Halt further ascent! May need to descend if symptoms are severe or not improving.
    • NSAIDs and Antiemetics. [Joy, 2015]
    • Acetazolamide: [Garlick, 2017; Joy, 2015]
      • 2.5 mg/kg/dose BID (max of 125 mg BID)
      • Usually not as effective as it is for prophylaxis.
    • Dexamethasone: [Garlick, 2017]
      • Used if symptoms are severe (along with descent).
      • 0.15 mg/kg/dose q 6 hrs.

• HIGH ALTITUDE PULMONARY EDEMA (HAPE)
  • Non-cardiogenic pulmonary edema caused by hypobaric hypoxia.
  • Presents with: [Garlick, 2017; Joy, 2015]
    • Dyspnea (particularly at rest), exercise intolerance, cough
    • Hemoptysis
    • Tachycardia, tachypnea, rales, cyanosis
  • Highest associated mortality rate of all of the HAIs.
  • Risk Factors for HAPE: [Garlick, 2017]
    • Children who live at higher altitude, who descend, then return to higher altitude (“re-entrant pulmonary edema“). [Joy, 2015; Polli, 2015]
    • Genetically predisposed
    • Elevations > 9,842 feet (3,000 meters)
    • More rapid ascent
    • Recent upper respiratory tract infection
  • Prevention:
    • Gradual ascent is best way to avoid HAPE.
    • Medication use (Diuretics and/or Nifedipine) have been used, but not studied and would be used off label. [Garlick, 2017]
  • Treatment:
    • Immediate descent… but without exertion (so carried down to lower altitude). [Garlick, 2017]
    • Supplemental Oxygen!
    • Medications have not been found to hasten recovery…
      • Used when oxygen therapy isn’t available. [Joy, 2015]
      • Nifedipine 30 mg Sustained Release q 12 hours.
      • Sildenafil 0.5 mg/kg/dose q 4-8 hours (max = 50 mg/dose)

• HIGH ALTITUDE CEREBRAL EDEMA (HACE)
  • Distinct from Acute Mountain Sickness by presence of neurologic impairment: [Garlick, 2017]
    • Ataxia, Confusion, Altered Mental Status
    • Can follow Acute Mountain Sickness though.
  • Very rare in children…
    • Likely related to being rare in adults and…
    • Primarily occurring at elevations > 13,123 feet (4,000 meters).
  • Treatment:
    • Immediate descent.
    • Supplemental Oxygen.
    • Dexamethasone: [Garlick, 2017]
      • 0.15 mg/kg/dose q 6 hrs.

Moral of the Morsel

• Kids travel to the highest of heights! Achievement is great… but High Altitude Illness is not!
• The Tortoise will beat the Hare! Ascending slowly is the key to prevention!
• Know who is at higher risk! Chronic lung conditions are particularly problematic!
• Going Home can make some sick! Re-Entrant Pulmonary Edema can be seen in children more than in adults.

References