Patient education: Altitude sickness (including mountain sickness) (The Basics)

What is altitude sickness? — Traveling to high altitudes can sometimes cause health problems (figure 1). This group of problems is called "altitude sickness." This can happen if you live at a low altitude and go to the mountains or a city that is at high altitude (for example, Mexico City or Denver, Colorado).

The 3 main types of altitude sickness are:

●Acute mountain sickness – This is the most common type and causes symptoms like those caused by an alcohol hangover.

●High-altitude cerebral edema (also called "HACE") – This is less common but more serious than acute mountain sickness. It involves swelling of the brain.

●High-altitude pulmonary edema (also called "HAPE") – This is also less common and more serious than acute mountain sickness. It involves fluid buildup in the lungs.

If you are planning to go somewhere at high altitude, there are things you can do to keep from getting altitude sickness.

What are the symptoms of altitude sickness? — The symptoms differ depending on the type of altitude sickness you have.

Acute mountain sickness can happen within a day of traveling or climbing to a very high altitude. The symptoms can include:

●Headache

●Feeling tired

●Feeling lightheaded

●Having no appetite

●Trouble sleeping

●Nausea, sometimes with vomiting

●Getting short of breath with exercise

If you have these symptoms, do not travel or climb any higher until you feel better. You should feel better within a day or so.

The symptoms of HACE (swelling of the brain) usually start 1 to 3 days after traveling or climbing to a high altitude. They include:

●Extreme tiredness and weakness

●Problems with coordination, for example, having trouble walking normally

●Confusion and irritability

●Acting drunk

The symptoms of HAPE (fluid in the lungs) usually start 2 to 4 days after traveling or climbing to a high altitude. They include:

●Coughing

●Feeling breathless

●Trouble walking uphill

Is there anything I can do on my own to feel better? — Yes. If you have mild symptoms of acute mountain sickness, you should rest. Do not travel or climb to a higher altitude until you feel better. If possible, moving to a lower altitude can also help. For a headache, you can take medicines such as aspirin, acetaminophen (sample brand name: Tylenol), or ibuprofen (sample brand names: Advil, Motrin).

You might be tempted to keep climbing, especially if you are with other people. But it's important to rest so you don't get worse. If you are climbing or traveling with someone who has symptoms of altitude sickness, stay with them so you can get help if needed.

If you have symptoms of a more serious problem, such as HACE or HAPE, try to get help right away and move to a lower altitude immediately.

Should I see a doctor or nurse? — If you have severe symptoms after traveling or climbing to a high altitude, get medical care right away. You should also get medical care if your symptoms are mild but don't improve over the first few days, or if you start feeling worse. Waiting to get treatment could cause serious health problems, or even death.

How is altitude sickness treated? — Treatment depends on which type of altitude sickness you have. If you have symptoms of acute mountain sickness, rest and stay where you are until you feel better. If your symptoms get worse, move to a lower altitude. Breathing in extra oxygen can also help. Many hotels and resorts at high altitude have oxygen available.

There are also prescription medicines that can help treat the symptoms of acute mountain sickness. These include:

●Acetazolamide (brand name: Diamox) – This medicine can help prevent and treat acute mountain sickness.

●Dexamethasone (brand name: Decadron) – This medicine can help keep the symptoms of acute mountain sickness from getting worse. It can also help prevent or treat swelling of the brain.

The most important treatment for HACE (swelling of the brain) or HAPE (fluid in the lungs) is to get to a lower altitude right away. If you have HACE or HAPE and cannot get to a lower altitude, you might be put inside a special inflatable bag called a "portable hyperbaric chamber" (picture 1). Once you are zipped inside this bag, it is filled up with air that is similar to the air at lower altitudes. You might also get extra oxygen to breathe.

Can altitude sickness be prevented? — Yes. The best way to prevent altitude sickness is to avoid moving quickly to a higher altitude. Increasing your altitude a little at a time, over several days, gives your body time to adjust:

●If you are traveling to a very high altitude, plan to stretch your trip out over several days

●If you are hiking or climbing, don't do difficult physical activities for the first few days, and avoid alcohol and sleeping pills

●When hiking, go to a higher altitude during the day and then go back down to a slightly lower altitude each night to sleep

●If you have had altitude sickness before, your doctor might give you a medicine to keep you from getting it again

More on this topic

Patient education: Hypothermia (The Basics)

Patient education: High-altitude illness (including mountain sickness) (Beyond the Basics)