II. Pathophysiology

  1. Life-threatening complication of High Altitude Sickness
  2. Cerebral Blood Flow results from Hypoxemia response
    1. Disordered autoregulation of cerebral Hypertension may result in vasogenic cerebral edema
    2. Increased blood brain barrier permeability
  3. Course from mild Ataxia to death can occur within hours

III. Symptoms

IV. Signs

  1. See High Altitude Sickness
  2. Hypertension
  3. Truncal Ataxia
    1. Screening: Heal-Toe Walking in a straight line
    2. Difficult ambulation
  4. Altered Mental Status (confusion to coma)
    1. May rapidly evolve from drowsy to confusion to coma without active treatment (esp. descent)
    2. Hallucinations

V. Diagnosis

  1. Criteria 1
    1. Mental status changes OR Ataxia and
    2. Acute Mountain Sickness criteria
  2. Criteria 2
    1. Mental status changes AND Ataxia
    2. Without Acute Mountain Sickness criteria

VI. Imaging (if available)

  1. Brain MRI
    1. Corpus Callosum edema
    2. Subcortical white matter edema
    3. Microhemorrhages with hemosiderin deposits may be seen months after recovery

VII. Management

  1. See High Altitude Sickness
  2. Gamow Bag
  3. Descend Immediately by at least 1000 meters (even 500 meters may be sufficient)
  4. Dexamethasone
    1. Initial: 8 mg IM/IV/PO Load
    2. Later: 4 mg every 6 hours IM/IV/PO
  5. High flow Supplemental Oxygen
    1. Keep Oxygen Saturation >90%
  6. Intubation and Hyperventilation if patient comatose

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