HIGH ALTITUDE CEREBRAL EDEMA (HAPE)
By Dr. Clare O'Leary and Pat Falvey.

High altitude cerebral edema (HACE) is a neurological syndrome resulting from dysfunction and injury of the central nervous system
due to the lack of oxygen at high altitude. It is associated with AMS
and HAPE.
 
SYMPTOMS OF HACE

• Uncoordination
• Unsteady walking
• Headache
• Vomiting
• Photophobia (dislike of light)
• Irritability
 226; Confusion
• Lethargy
• Hallucinations
• Urinary incontinence
• Irrational behaviour

The incidence is less than pulmonary edema and the altitude of occurrence is higher. It typically occurs 5-7 days after ascent to >9,000 ft (2,750m). It usually progresses over a period of hours or days; if untreated the patient will die. Any patient with AMS who develops neurological signs, clouding of consciousness or hallucinations should be treated for HACE.
 
SIGNS OF HACE

• Unsteady gait - Ask the patient to walk heel-to-toe and turn around
--quickly without losing balance
• Impaired mental acuity - Ask the patient to count backwards from
--100 in 7s
• Rapid heart rate
• Cyanosis (bluish discoloration of lips/tongue)
• Papilloedema (swelling at the back of the eye)
• Retinal haemorrhage (bleed at the back of the eye)
• Extensor plantar response (abnormal foot reflex)
• Drowsiness
• Unconsciousness

 
PREVENTION OF HACE

• Ascend at a slow rate
• Avoid over-exertion
• Consider acetazolamide prophylaxis (125-250mg twice daily)
--beginning 1 day before ascent and continuing for 2 days at high altitude
• Treat AMS early
 
TREATMENT OF HACE

• Immediate descent
• Supplementary oxygen 4-6l/min
-- (O2 saturation should improve to >90% after 5mins)
• Portable hyperbaric chamber
• Dexamethasone 8mg (orally/intramuscularly/intravenously)
-- initially, then 4mg 6hrly.
• Acetazolamide if descent is delayed