What is acute mountain sickness?
Hikers, skiers, and adventurers who travel to high altitudes can sometimes develop acute mountain sickness. Other names for this condition are altitude sickness or high altitude pulmonary edema. It typically occurs at about 8,000 feet, or 2,400 meters, above sea level. Dizziness, nausea, headaches, and shortness of breath are a few symptoms of this condition. Most instances of altitude sickness are mild and heal quickly. In rare cases, altitude sickness can become severe and cause complications with the lungs or brain.
What causes acute mountain sickness?
Higher altitudes have lower levels of oxygen and decreased air pressure. When you travel in a plane, drive or hike up a mountain, or go skiing, your body may not have enough time to adjust. This can result in acute mountain sickness. Your level of exertion also plays a role. Pushing yourself to quickly hike up a mountain, for example, may cause acute mountain sickness.
What are the symptoms of acute mountain sickness?
The symptoms of acute mountain sickness generally appear within hours of moving to higher altitudes. They vary depending on the severity of your condition.
Mild acute mountain sickness
If you have a mild case, you may experience:
- muscle aches
- nausea and vomiting
- loss of appetite
- swelling of the hands, feet, and face
- rapid heartbeat
- shortness of breath with physical exertion
Types of AMS
High-altitude cerebral edema (HACE) occurs if acute mountain sickness persists. HACE is a severe form of AMS where the brain swells and stops functioning normally. Symptoms of HACE resemble severe AMS. The most notable symptoms include:
- extreme drowsiness
- confusion and irritability
- trouble walking
If not treated immediately, HACE can cause death.
High-altitude pulmonary edema (HAPE) is a progression of HACE, but it can also occur on its own. Excess fluid builds up in the lungs, making it difficult for them to function normally. Symptoms of HAPE include:
- increased breathlessness during exertion
- severe coughing
If HAPE isn’t treated promptly by decreasing altitude or using oxygen, it can lead to death.
Severe acute mountain sickness
Severe cases of acute mountain sickness can cause more intense symptoms and affect your heart, lungs, muscles, and nervous system. For example, you may experience confusion as a result of brain swelling. You may also suffer from shortness of breath due to fluid in the lungs.
Symptoms of severe altitude sickness may include:
- chest congestion
- pale complexion and skin discoloration
- inability to walk or lack of balance
- social withdrawal
Who is at risk for acute mountain sickness?
Your risk of experiencing acute mountain sickness is greater if you live by or near the sea and are unaccustomed to higher altitudes. Other risk factors include:
- quick movement to high altitudes
- physical exertion while traveling to a higher altitude
- traveling to extreme heights
- a low red blood cell count due to anemia
- heart or lung disease
- taking medications like sleeping pills, narcotic pain relievers, or tranquilizers that can lower your breathing rate
- past bouts of acute mountain sickness
If you’re planning on traveling to a high elevation and have any of the above conditions or take any of the above medications, talk to your doctor about how best to avoid developing acute mountain sickness.
How is acute mountain sickness treated?
Treatment for acute mountain sickness varies depending on its severity. You might be able to avoid complications by simply returning to a lower altitude. Hospitalization is necessary if your doctor determines that you have brain swelling or fluid in your lungs. You may receive oxygen if you have breathing issues.
Medications for altitude sickness include:
- Acetazolamide, to correct breathing problems
- blood pressure medicine
- lung inhalers
- Dexamethasone, to decrease brain swelling
- Disprine, for headache relief
Some basic interventions may be able to treat milder conditions, including:
- returning to a lower altitude
- reducing your activity level
- resting for at least a day before moving to a higher altitude
- hydrating with water
How can I prevent acute mountain sickness?
You can take some important preventive steps to reduce your chances of acute mountain sickness. Get a physical to make sure you have no serious health issues. Review the symptoms of mountain sickness so you can recognize and treat them quickly if they occur. If traveling to extreme altitudes (higher than 10,000 feet, for example), ask your doctor about acetazolamide, a medication that can ease your body’s adjustment to high altitudes. Taking it the day before you climb and on the first day or two of your trip can lessen your symptoms.
When climbing to higher altitudes, here are some tips that can help you avoid developing acute mountain sickness:
What’s the long-term outlook?
Most people are able to recover from a mild case of acute mountain sickness quickly after returning to lower altitudes. Symptoms typically subside within hours, but may last up to two days. However, if your condition is severe and you have little access to treatment, complications can lead to swelling in the brain and lungs, resulting in coma or death. It’s essential to plan ahead when traveling to high-altitude locations.
What are the complications of altitude sickness?
Complications of altitude sickness include:
- pulmonary edema (fluid in the lungs)
- brain swelling
Can you prevent altitude sickness?
Know the symptoms of altitude sickness before you ascend. Never go to a higher altitude to sleep if you’re experiencing symptoms. Descend if symptoms get worse while you’re at rest. Staying well hydrated can decrease your risk for developing altitude sickness. Also, you should minimize or avoid alcohol and caffeine, as both can contribute to dehydration.