Ver el código de «High altitude cerebral edema»

==Background==
*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==
*Will have clinical features of [[acute mountain sickness]] before HACE, as HACE is a progression from [[AMS]]
*[[Altered mental status]], [[ataxia]], gait disturbance, stupor (most sensitive findings)
**Ataxia at high altitude is cerebral edema until proven otherwise
**Progresses to [[coma]] if untreated 
*Uncertain mechanism, presumed cause is hypoxia leading to cerebral edema
*[[Headache]], [[nausea/vomiting]] (not always present)
*[[Focal neuro deficits]] may be seen ([[CN III palsy|3rd]]/[[abducens nerve palsy|6th]] CN palsies)
*[[Seizures]] are rare

==Differential Diagnosis==
{{High altitude DDX}}
*[[Dehydration]]
*Exhaustion
*[[Hypoglycemia]]
*[[Hypothermia]]
*[[Hyponatremia]]
*[[Carbon monoxide]] poisoning
*[[Stroke]]
*[[Meningitis]]
*[[Encephalitis]]
*CNS lesion
*Intoxication

==Evaluation==
[[File:PMC3775198 LI-30-193-g007.png|thumb|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<ref>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)</ref>
*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<ref>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.</ref>

{{Expected SpO2 at altitude}}

==Management==
[[File:Altitude flow sheet.png|thumb|High altitude management algorithm.]]
*Immediate descent is the treatment of choice 
*If descent not possible use combination of: 
**Supplemental [[O2]] (goal SpO2 90%)<ref>Hackett PH, Roach RC. High altitude cerebral edema. High Alt Med Biol 2004; 5:136-146.</ref>
**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.

==Prevention==
*Acclimatization, slow ascent
*[[Acetazolamide]] 125mg BID (250mg BID if greater than 100kg)
*[[Dexamethasone]] 4mg q6h PO or IV

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

==See Also==
*[[High Altitude Medicine]]

==References==
<references/>

[[Category:Environmental]]