High altitude cerebral edema

(Redirected from HACE)


  • Also known as HACE
  • Progressive neurologic deterioration in someone with acute mountain sickness or HAPE (due to ↑ ICP)
  • Least common form of acute mountain sickness
  • Typically occurs three to five days after arrival of high elevation
  • Almost never occurs at <8,000ft (~2000m)

Clinical Features

Differential Diagnosis

High Altitude Illnesses


Head CT of HACE showing diffuse effacement of cerebral sulci and compression of ventricles.
  • The Lake Louise Consensus Criteria for HACE
    • The presence of a change in mental status OR ataxia in a person with AMS
    • OR the presence of BOTH a change in mental status and ataxia in a person without AMS
  • Lumbar puncture is not required, but if performed, will generally show elevated opening pressures (>44 mmH2O) and normal fluid analysis[1]
  • CT or MRI may be confirmatory, but not necessary. Most beneficial to rule out alternative etiologies. If performed, may show signs of vasogenic edema. MRI will show white matter edema (increased T2 signal), particularly in the corpus callosum[2]

Expected SpO2 and PaO2 levels at altitude[3]

Altitude SpO2 PaO2 (mm Hg)
1,500 to 3,500 m (4,900 to 11,500 ft) about 90% 55-75
3,500 to 5,500 m (11,500 to 18,000 ft) 75-85% 40-60
5,500 to 8,850 m (18,000 to 29,000 ft) 58-75% 28-40


High altitude management algorithm.
  • Immediate descent is the treatment of choice
  • If descent not possible use combination of:
    • Supplemental O2 (goal SpO2 90%)[4]
    • Supportive hyperventilation
    • Dexamethasone 8mg initially (PO, IM, or IV), then 4mg q6hr
    • Acetazolamide 250mg BID (better as ppx)
    • Hyperbaric bag (Gamow bag) if available
    • Of note, furosemide, mannitol, and oral glycerol have all been studied but have undetermined effectiveness at this time.



  • Admission for close monitoring, neurological checks
  • Recovery ranges from 2 to 21 days with 25% of patients recovering within 48 hours

See Also


  1. Medical Aspects of Harsh Environments Vol 2: Textbook of Military Medicine Series. Published by The US Army office of the surgeon general 2002. (Text, review)
  2. Hackett PH, Yarnell PR, Hill R, Reynard K, Heit J, McCormick J. High-altitude cerebral edema evaluated with magnetic resonance imaging: clinical correlation and pathophysiology. JAMA. 1998;280(22):1920-1925.
  3. Gallagher, MD, Scott A.; Hackett, MD, Peter (August 28, 2018). "High altitude pulmonary edema". UpToDate. Retrieved May 2, 2019.
  4. Hackett PH, Roach RC. High altitude cerebral edema. High Alt Med Biol 2004; 5:136-146.