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Focused History: When did the symptoms begin? (typically begin 3-10 days after ascent; later than AMS)
Have you had symptoms of AMS? (risk factor; worsening AMS symptoms after 48–72 hours are likely due to
HACE.) How is your coordination? Have you been stumbling or falling? (Ataxia and clumsiness are typical.)
Are you seeing or hearing unexpected or unusual things (having hallucinations)? Do you have a cough or
difficulty breathing? (typical of HAPE; accompanies 1/3 of HACE cases) Have you taken any medications,
drugs or alcohol? (Intoxication could cause similar symptoms.) Have you been in a tent, cave or vehicle with a
stove or motor running? (Carbon monoxide poisoning could cause similar symptoms.)
Objective: Signs
Using Basic Tools: Early: Behavioral changes (agitated or quiet and withdrawn); later: disorientation,
confusion, ataxia (cannot do ‘heel-to-toe-walk’), incoordination and often hallucinations (visual and auditory);
abnormal deep tendon reflexes, decreased consciousness, coma and death; may have rales, cough, and
frothy, pink or bloody sputum (concomitant HAPE).
Using Advanced Tools: Ophthalmoscope: Retinal hemorrhages and swelling of optic nerve in the back of
the eye (papilledema). Pulse oxygen levels will be lower with HACE or other altitude illnesses.
Assessment:
Differential Diagnosis
Other causes of headache - migraine, cluster, or tension headache; infection. History of headache at low
altitude. Check for stiff neck, fever or increased white cell count (see Neurology: Meningitis).
Head trauma
Intoxication - history of ingesting medications, recreational drugs, alcohol (see Toxicology: Poisoning).
Carbon monoxide poisoning - history of exposure to combustion fumes (see Toxicology: Poisoning).
Hypothermia - lack of headache and nausea. Decreased body temperature (see Cold Illnesses: Hypother-
mia.)
Hyperthermia and/or dehydration - history of decreased fluid intake, elevated body temperature (see Heat-
Related Illnesses).
AMS - HACE patients have papilledema and/or ataxia, and may have deteriorating mental status.
Plan:
Treatment
Primary:
- Evacuate to lower altitude immediately (1000 to 2000 feet change may be lifesaving).
- Oxygen: 6 L/minute or more by oxygen mask. Insert endotracheal tube if comatose.
- Dexamethasone 8mg initially, then 4mg every six hours po or IV.
- Evacuate patient to advanced medical care.
Alternative: Oxygen, dexamethasone and portable hyperbaric (‘pressure’) chamber*. (see Procedures:
Portable Pressure Chamber 8-
Primitive: Descent is the best treatment for all altitude illnesses (e.g., AMS, HACE, HAPE.)
Patient Education
General: HACE is caused by rapid ascent before the body can adjust to altitude. Symptoms will worsen
with further ascent.
Activity: Bed rest or very limited activity - can descend under own power in emergency if accompanied
Medications: Dexamethasone can cause psychosis, puffy face, and increase appetite. Taper the dose
after taking for >3-4 days.
Prevention and Hygiene: Ascend slowly (less than 1000 ft/day) with rest day every 3-4 days. Do not
continue ascending with symptoms of altitude illness. Sleep at as low an altitude as possible (1000-2000 ft
lower than working altitude) until body adjusts to altitude (7-10 days). Acetazolamide 125-250 mg po tid/qid
beginning 12-24 hours before ascending may help prevent HACE. NOTE: Individuals with allergic reactions to
sulfa-containing substances should not be given acetazolamide.
No Improvement/Deterioration: HACE is rapidly fatal if not treated. Seek medical attention if have
headache and difficulty with balance or have hallucinations. HACE is often accompanied by HAPE. Seek