Who is affected

AMS can affect any visitor sleeping above 6,000 feet.

Incidence

25–40% of visitors sleeping at 8,000 feet or higher will develop AMS.

Cause

Believed to be related to low oxygen levels in the blood, which leads to dilation of blood vessels in the brain, causing swelling and increased pressure.

Symptoms

Headache, nausea/vomiting, loss of appetite, dizziness/lightheadedness, fatigue, trouble sleeping. AMS often feels like a bad hangover.

Risk Factors

Rapid ascent to altitude without spending a night at an intermediate elevation (such as Denver, 5,000 ft), history of previous AMS, recent respiratory illness, overexertion upon arrival, alcohol use, sedating medications, residence below 3,000 ft, and genetic predisposition.

Treatment

• Do not ascend to a higher altitude until symptoms resolve.

• Tylenol (acetaminophen) and ibuprofen are safe for headaches.

• Stay adequately hydrated; urine should be clear or light-colored. IV fluids can help speed up rehydration if needed.

• Oxygen therapy can provide relief within minutes; sleeping on oxygen is also beneficial.

• Prescription medications: Acetazolamide (Diamox) or dexamethasone (Decadron) may be used.

• Warning: If left untreated, AMS can progress to a serious, life-threatening form called HACE (High Altitude Cerebral Edema). THIS IS A 911 EMERGENCY!

What it is

HAPE is a serious form of altitude illness that causes fluid to accumulate in the lungs.

Onset

Symptoms typically start within 2–4 days at altitude.

Cause

Constriction of the arteries supplying the lungs in response to low oxygen leads to increased pressure and fluid leakage into the lungs.

Symptoms

Shortness of breath with activity, progressing to shortness of breath at rest; persistent cough (sometimes with pink, foamy, or bloody sputum); chest tightness.

Risk Factors

Rapid ascent to altitude, male gender, recent respiratory illness, overexertion at altitude, history of heart or lung problems.

Treatment

• Oxygen therapy.

• Descent to a lower altitude may be necessary.

• Prescription medications: Nifedipine, sildenafil (Viagra), or tadalafil (Cialis).

What it is

HACE is a severe, life-threatening form of altitude illness. CALL 911 if you suspect someone has HACE.

Onset

Symptoms usually begin within 2–4 days at altitude, often in someone who had symptoms of AMS that were ignored.

Cause

Believed to be due to low oxygen levels in the blood, leading to dilation of blood vessels in the brain, swelling, and increased pressure.

Symptoms

Severe headache, vomiting, confusion, loss of balance, and combative or unusual behavior.

Risk Factors

Rapid ascent to altitude, use of sedating medications, history of HACE.

Treatment

• Oxygen therapy.

• Immediate descent to a lower altitude.

• Prescription medication: Dexamethasone.

If you or someone you know is experiencing severe symptoms at altitude, seek emergency medical attention immediately. Prompt recognition and treatment can be lifesaving.