High Altitude Cerebral Edema
(Redirected from HACE)
Other Names
- High Altitude Cerebral Edema (HACE)
Background
- This page refers to High Altitude Cerebral Edema (HACE), a life threatening form of Acute Mountain Sickness
History
Epidemiology
- Occurs in less than 1% of visitors to altitude (need citation)
Pathophysiology
- General
- Serious, life threatening condition
- Typically occurs at very high or extreme altitudes, but has been documented below 3000 m[1]
- It should be considered in anyone experiencing AMS, regardless of symptoms
- Onset is typically several days after arriving at altitude, but can occur within hours
Etiology
- Cerebral Edema
- Develops following cerebral vasodilation secondary to hypoxia
- Hypoxemia results in overperfusion of microvasculature, increased hydrostatic pressure, leakage from capillaries[2]
- Autopsies reveal edema
- Magnetic resonance imaging (MRI) studies demonstrate white matter changes splenium of the corpus callosum (consistent with edema)[3]
Associated Conditions
- Acute Mountain Sickness (AMS)
- Approximately 3.4% of patients with AMS develop HACE (need citation)
- High Altitude Pulmonary Edema (HAPE)
- Between 13 and 20% of patients with HACE also have HAPE (need citation)
Risk Factors
Differential Diagnosis
- Neurologic/ Ophtho
- Migraine
- Transient Ischemic Attack
- Stroke
- Cerebral Venous Thrombosis
- Cranial nerve palsies
- Ophthalmological disturbances (cortical blindness, retinal hemorrhage)
- Cognitive slowing
- Emotional liability
- Metabolic
- Environmental
Clinical Features
- History
- Symptoms are typically similar to those with AMS, but more severe
- Includes headache, nausea and vomiting, fatigue,
- Physical Exam
- Ataxia
- Altered consciousness (confusion, irrational behavior, lethargy, impaired cognition, stupor, and coma)
- Papilledema
- Retinal hemorrhage
- Focal neurologic deficits
- Special Tests
Evaluation
- No special tests are required to diagnose HACE
- It should be the presumed diagnosis in any patient with neurological symptoms after ascending to altitude
Classification
- Currently no classification exists
Management
Prevention
Treatment
- Immediate Descent
- By helicopter if possible
- Supplemental Oxygen
- Maximum flow rate to maintain oxygen saturation above 90%
- Dexamethasone
- 8 mg loading dose followed by 4 mg every 6 hours
- Portable Hyperbaric Chamber
- Should be used if available, especially if evacuation is delayed
- If patient has nausea and vomiting or requires airway management, this option remains challenging
- Should not delay descent
Rehab and Return to Play
Rehabilitation
- Needs to be updated
Return to Play/ Work
- Little evidence is present to guide team physicians
- Clinical judgement is paramount
- Recovery from HACE is highly variable[4]
- Ranges from days to up to 12 weeks
- Immediate return is not advised
- Return to altitude where HACE developed will need to occur at a slower pace
- Staged ascent with stops along the way
- Consider prophylaxis with Acetazolamide
Complications and Prognosis
Prognosis
- Recovery
- Full recovery occurs in most patients
- Permanent neurologic impairment an occur
Complications
- Death
- Occurs due to brain herniation from unchecked cerebral edema
- Neurologic Defecits
See Also
References
- ↑ Hackett PH, Roach RC. High-altitude illness. In: Auerbach PS, editor. Wilderness Medicine, 5th ed., Philadelphia: Mosby; 2007, p. 2Y35.
- ↑ Hackett PH, Roach RC. High-altitude illness. N Engl J Med 2001; 345: 107–114.
- ↑ 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: 1920–1925.
- ↑ Yarnell PR, Heit J, Hackett PH. High-altitude cerebral edema (HACE): the Denver/Front Range experience. Semin. Neurol. 2000; 20:209Y17.
Created by:
John Kiel on 30 June 2019 23:00:12
Authors:
Last edited:
24 April 2022 12:36:41
Categories: