Encyclopedia Home / A / Acute mountain sickness

Acute mountain sickness

  • Alternative Names

    High altitude cerebral edema; Altitude anoxia; Altitude sickness; Mountain sickness; High altitude pulmonary edema


    Early diagnosis is important. Acute mountain sickness is easier to treat in the early stages.

    The main treatment for all forms of mountain sickness is to climb down (descend) to a lower altitude as rapidly and safely as possible. You should not continue climbing if you develop symptoms.

    Extra oxygen should be given, if available.

    People with severe mountain sickness may need to be admitted to a hospital.

    Acetazolamide (Diamox) may be given to help improve breathing and reduce mild symptoms. This drug can cause increased urination. Make sure you drink plenty of fluids and avoid alcohol when taking this drug.

    If you have fluid in your lungs (pulmonary edema), treatment may include:

    • Oxygen
    • A high blood pressure medicine called nifedipine
    • A type of drug called a phosphodiesterase inhibitor (such as sildenafil)
    • Lung inhalers beta agonists
    • A breathing machine, in severe cases

    Dexamethasone (Decadron) may help reduce swelling in the brain (cerebral edema).

    Portable hyperbaric chambers allow hikers to simulate conditions at lower altitudes without actually moving from their location on the mountain. These devices are very helpful if bad weather or other factors make climbing down the mountain impossible.

    Support Groups

    Expectations (prognosis)

    Most cases are mild, and symptoms improve promptly when you climb down the mountain to a lower altitude.

    Severe cases may result in death due to lung problems or brain swelling.

    In remote locations, emergency evacuation may not be possible, or treatment may be delayed. This can have a negative affect on your outcome.

    • Coma
    • Fluid in the lungs (pulmonary edema)
    • Swelling of the brain

    Calling your health care provider

    Call your health care provider if you have or had symptoms of acute mountain sickness, even if you felt better when you returned to a lower altitude.

    Call 911 or your local emergency number if you or another climber have any of the following symptoms:

    • Severe breathing problems
    • Altered level of alertness
    • Coughing up blood

    Climb down the mountain immediately and as safely as possible.