II. Pathophysiology
- Life-threatening complication of High Altitude Sickness
- Cerebral Blood Flow results from Hypoxemia response
- Disordered autoregulation of cerebral Hypertension may result in vasogenic cerebral edema
- Increased blood brain barrier permeability
- Course from mild Ataxia to death can occur within hours
III. Symptoms
- See High Altitude Sickness
- Headache
- Fatigue
- Photophobia
IV. Signs
- See High Altitude Sickness
- Hypertension
- Truncal Ataxia
- Screening: Heal-Toe Walking in a straight line
- Difficult ambulation
-
Altered Mental Status (confusion to coma)
- May rapidly evolve from drowsy to confusion to coma without active treatment (esp. descent)
- Hallucinations
V. Diagnosis
- Criteria 1
- Mental status changes OR Ataxia and
- Acute Mountain Sickness criteria
- Criteria 2
- Mental status changes AND Ataxia
- Without Acute Mountain Sickness criteria
VI. Imaging (if available)
- Brain MRI
- Corpus Callosum edema
- Subcortical white matter edema
- Microhemorrhages with hemosiderin deposits may be seen months after recovery
VII. Management
- See High Altitude Sickness
- Gamow Bag
- Descend Immediately by at least 1000 meters (even 500 meters may be sufficient)
-
Dexamethasone
- Initial: 8 mg IM/IV/PO Load
- Later: 4 mg every 6 hours IM/IV/PO
- High flow Supplemental Oxygen
- Keep Oxygen Saturation >90%
- Intubation and Hyperventilation if patient comatose
VIII. References
- Comp and Rogich (2021) Crit Dec Emerg Med 35(4): 3-8
- Basnyat (2003) Lancet 361(9373): 1967-74 [PubMed]
- Fiore (2010) Am Fam Physician 82(9): 1103-10 [PubMed]
- Hackett (2001) N Engl J Med 345(2): 107-14 [PubMed]
- Wu (2006) High Alt Med Biol 7(4): 275-80 [PubMed]