High altitude cerebral edema

Background

• Also known as HACE
• Progressive neurologic deterioration in someone with AMS or HAPE (due to ↑ ICP)
• Almost never occurs at <8000ft

Clinical Features

• Altered mental status, ataxia, gait disturbance, stupor (most sensitive findings)
  • 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

Evaluation

Head CT of HACE showing diffuse effacement of cerebral sulci and compression of ventricles.

• Clinical diagnosis

Management

High altitude management algorithm.

• Immediate descent is the treatment of choice
• If descent not possible use combination of:
  • Supplemental O2 (goal SpO2 90%)
  • 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

See Also

• High Altitude Medicine