High altitude cerebral edema: Difference between revisions
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*[[Hypothermia]] | *[[Hypothermia]] | ||
*[[Hyponatremia]] | *[[Hyponatremia]] | ||
*[[Carbon monoxide]] poisoning | |||
*[[Stroke]] | |||
*[[Meningitis]] | |||
*[[Encephalitis]] | |||
*CNS lesion | |||
*Intoxication | |||
==Evaluation== | ==Evaluation== | ||
Revision as of 23:54, 22 May 2021
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 illness 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 (3rd/6th CN palsies)
- Seizures are rare
Differential Diagnosis
High Altitude Illnesses
- Acute mountain sickness
- Chronic mountain sickness
- High altitude cerebral edema
- High altitude pulmonary edema
- High altitude peripheral edema
- High altitude retinopathy
- High altitude pharyngitis and bronchitis
- Ultraviolet keratitis
- Dehydration
- Exhaustion
- Hypoglycemia
- Hypothermia
- Hyponatremia
- Carbon monoxide poisoning
- Stroke
- Meningitis
- Encephalitis
- CNS lesion
- Intoxication
Evaluation
- 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
Expected SpO2 and PaO2 levels at altitude[1]
| 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 |
Management
- Immediate descent is the treatment of choice
- If descent not possible use combination of:
- Supplemental O2 (goal SpO2 90%)[2]
- Supportive hyperventilation
- Dexamethasone 8mg initially (PO, IM, or IV), then 4mg q6hr
- Acetazolamide 250mg BID (better as ppx)
- Hyperbaric bag (Gamow bag) if available
Prevention
- Acclimatization, slow ascent
- Acetazolamide 125mg BID (250mg BID if greater than 100kg)
- Dexamethasone 4mg q6h PO or IV