Altitude Sickness (Mountain Sickness) Causes, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

Altitude Sickness (Mountain Sickness) Causes, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

What is Altitude Sickness (Mountain Sickness)?

Altitude sickness  (also known as mountain sickness) occurs when you cannot get enough oxygen from the air at high altitudes. This causes symptoms such as a headache, loss of appetite, and trouble sleeping. It happens most often when people who are not used to high altitudes go quickly from lower altitudes to 8000 ft (2438 m) or higher. For example, you may get a headache when you drive over a high mountain pass, hike to a high altitude, or arrive at a mountain resort.

Altitude Sickness (Mountain Sickness) Causes, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

Mild altitude sickness is common. In the United States, more than 20% of people visiting the western mountains get it.1 Experts do not know who will get it and who will not. Being male or female and your fitness level play no role in whether you get altitude sickness.

Men are at greater risk of altitude sickness than women, for reasons unknown. It is important to remember that being young and fit doesn't reduce your risk, and just because you haven't experienced altitude sickness in the past, doesn't mean you are immune to the condition during future climbs. The only sure method of prevention is to take plenty of time to ascend.

Altitude sickness can be dangerous. It is smart to take special care if you go high-altitude hiking or camping (like in the Rockies) or have plans for a vacation or trek in high-altitude countries like Peru, Ecuador, or Nepal.

Altitude sickness is also called acute mountain sickness.

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What causes Altitude Sickness (Mountain Sickness)?

Air is "thinner" at high altitudes. When you go too high too fast, your body cannot get as much oxygen as it needs. This causes the headache and other symptoms of altitude sickness. As your body gets used to the altitude, the symptoms go away.

What are the symptoms of Altitude Sickness (Mountain Sickness)?

The symptoms of altitude sickness include:

Altitude Sickness (Mountain Sickness) Causes, Symptoms, Diagnosis, Treatment, Prevention, Home Remedies

  • A headache, which is usually throbbing. It gets worse during the night and when you wake up.
  • Not feeling like eating.
  • Feeling sick to your stomach. You may vomit.
  • Feeling weak and lazy. In severe cases, you do not have the energy to eat, dress yourself, or do anything.
  • Waking up during the night and not sleeping well.
  • Feeling dizzy.

Symptoms of mild Altitude Sickness (Mountain Sickness)

Short-term altitude sickness also include dizziness, fatigue, shortness of breath, loss of appetite, sleep problems and a general loss of energy. Symptoms usually begin within 12 to 24 hours of arriving at a high altitude. Symptoms lessen within a day or two as the person gets used to the altitude.

Symptoms of moderate Altitude Sickness (Mountain Sickness)

Symptoms of moderate altitude sickness are more intense and are not relieved by over-the-counter medicines. Fatigue, weakness and shortness of breath worsen instead of improving over time. The affected person may start to show loss of coordination and have difficulty walking, severe headache that is not relieved by medicines, nausea and vomiting, and tightness or congestion in the chest. Normal activity is difficult, although the person may still be able to walk on his or her own.

Symptoms of severe Altitude Sickness (Mountain Sickness)

Symptoms of severe altitude sickness include shortness of breath at rest, inability to walk, confusion and fluid buildup in the lungs and/or brain. Other symptoms may include cough and a gray, pale or bluish skin tone. Severe altitude sickness is an emergency situation, and the affected person must be taken to a lower altitude immediately.

Who is at risk for Altitude Sickness (Mountain Sickness)?

Altitude sickness can affect anyone who goes to high altitudes without giving the body time to adjust to the changes in air pressure and oxygen level. High altitude is defined as 8,000 - 12,000 feet above sea level. Very high altitude is 12,000 - 18,000 feet, and altitudes above 18,000 feet are considered extremely high altitude.  For comparison, New York City has an altitude of 33 feet, Indianapolis, Ind. has an altitude of 797 feet, Denver, Colo. (the “Mile-High City” ) is at 5,000 feet, and the Grand Canyon is 6,600 feet above sea level.

The more rapidly a climb to high altitude, the more likely that altitude sickness will develop. Altitude sickness also is more likely to develop when climbs are more difficult and take more energy, compared with a slow and easy climb.

Age, sex and general health do not seem to make a difference in risk for altitude sickness. However, people with lung or heart disease may be told to avoid high altitudes. People who live at lower elevations and are not used to higher altitudes and people who have had altitude sickness previously seem to have a higher risk for altitude sickness.

Skiers, hikers and anyone planning a trip to location at a significantly higher than what they are used to should be know the signs and symptoms of altitude sickness and how to prevent and treat it.

Pregnant women should ask their doctor before traveling to a high altitude location.

How is Altitude Sickness (Mountain Sickness) diagnosed?

When headache plus one other symptom occur within 24 to 48 hours of changing elevation, altitude sickness should be considered. Most experienced climbers recognize the symptoms in people who are experiencing mild to moderate altitude sickness.

In cases of severe altitude sickness, a doctor will make the diagnosis based on signs, symptoms and the situation (the person was at a high altitude). The doctor may listen to the chest with a stethoscope or take a chest X-ray to determine whether there is any fluid in the chest. In the most severe cases, a doctor may order a brain MRI or CT scan to check for fluid in the brain.

How is Altitude Sickness (Mountain Sickness) treated?

It is very important to know the symptoms of altitude sickness so that treatment can be started early while the illness is still mild.

For all stages of altitude sickness, the main treatment is to go down to a lower altitude as quickly and safely as possible. For mild altitude sickness, over-the-counter medicines should relieve headache. Other symptoms will go away quickly at a lower altitude.

Symptoms of moderate altitude sickness usually improve in 24 hours at an elevation that is at least 1,000 to 2,000 feet lower. Symptoms should go away completely within 3 days.

People who have severe altitude sickness must be taken to a lower elevation (no higher than 4,000 feet) immediately. They must be seen by a doctor as soon as possible. Hospital care may be needed.

Fluid in the brain (cerebral edema) may be treated with dexamethasone, a steroid that can help reduce swelling in the brain.

Treatment for fluid in the lungs (pulmonary edema) may include:

  • Additional oxygen
  • Medicines
  • A lung inhaler
  • A respirator (for the most severe cases)
Some highly skilled climbers and hikers may carry a portable oxygen chamber, also called a hyperbaric oxygen chamber, with them as part of their standard high-altitude gear. The “chamber” is a body bag that is pumped full of air. Inflating the bag increases the oxygen concentration allowing the person in the bag with altitude sickness to breathe in more oxygen.

Medicines. Acetazolamide is a prescription drug that increases a person’s breathing rate so that more oxygen is taken in. It helps the body adjust to higher altitudes more quickly and reduces minor symptoms of altitude sickness. Dexamethasone is also a prescription drug that is sometimes used to prevent altitude sickness.

What are the after-effects of Altitude Sickness (Mountain Sickness)?

Most people who get altitude sickness only get the mild form. Symptoms lessen when the person returns to a lower altitude. There are no lasting adverse effects. Even moderate altitude sickness resolves fairly quickly when the affected person descends to a lower elevation. After 2 or 3 days, the person can safely climb to higher elevations if desired.

Individuals who develop severe altitude sickness with swelling and fluid in the lungs or brain can be at risk of serious complications, including coma or death. Prompt treatment reduces the risk.

How can Altitude Sickness (Mountain Sickness) be prevented?

The best way to prevent altitude sickness is by acclimatization. This is a process that allows your body time to adapt to the change in oxygen concentration at a higher altitude. In general, this means climbing to a higher level at a slow pace.

Changes that occur in the body that help it acclimate to a higher elevation include:

  • Deeper breathing
  • Higher pressure in the lung arteries so more lung space is used to help breathe
  • Making more red blood cells to carry more oxygen to the body
  • Increasing the amount of oxygen released from the blood to the body tissues

Guidelines for proper acclimatization include:

  • If possible, start below 10,000 feet and walk to high altitude instead of driving or flying. If you must fly or drive to an altitude over 10,000 feet, stay at your first stop for 24 hours before going higher.
  • When hiking or climbing above 10,000 feet increase your altitude by no more than 1,000 feet a day and build a rest day into your schedule for every 3,000 feet gained. Remember, “Climb high and sleep low,” meaning if you climb more than 1,000 feet in a day, come down to sleep at a lower altitude.
  • Always move to a lower altitude if symptoms of altitude sickness develop.
  • Drink at least 3 to 4 quarts of water per day.
  • Avoid tobacco, alcohol and other depressant drugs, including barbiturates, tranquilizers and sleeping pills.
  • While at a high altitude, eat a diet that includes more than 70% carbohydrates.
  • Know the early signs and symptoms of altitude sickness and take action to prevent it from worsening.
Climbing experts recommend taking along enough tanks of oxygen to last for several days when traveling above 10,000 feet. Individuals at risk for developing low levels of oxygen in the blood (anemia) should ask their doctor about taking an iron supplement to help maintain blood oxygen levels.

What if you have a lung problem or other disease?

Experts do not know much about how altitude affects other diseases. Many people with allergic asthma do better at high altitudes. Still, if you have asthma and are going to high altitudes, continue to use your usual medicine and take your reliever medicine with you. Talk with your doctor about altitude sickness if you have long-term diseases, especially heart problems, sickle cell anemia, chronic obstructive pulmonary disease (COPD), or sleep apnea.

Altitude Sickness (Mountain Sickness) Home Remedies

Delay further ascent until symptoms improve.

Rest and stay warm.

Take acetaminophen (Tylenol) for headache.

Do not use sleeping pills or other central nervous system depressants to treat insomnia because they can suppress breathing.

If symptoms continue, do not travel any higher.

If symptoms worsen, descend approximately 1,000-2,000 feet (300-600 meters) immediately.

If descent is not possible, a portable hyperbaric chamber (Gamow bag) can be used to simulate a lower altitude.
  • The higher the altitude at which a hyperbaric chamber is used, the greater the apparent descent can be simulated. (This is because portable hyperbaric chambers can increase atmospheric pressure by 2 pounds per square inch.)
  • For example, a hyperbaric chamber at 9,800 feet (3,000 meters) can simulate a descent of 4,800 feet (1,500 meters), but the same hyperbaric chamber used at 24,600 feet (7,500 meters) can simulate a descent of 7,800 feet (2,400 meters).

First aid for Altitude Sickness (Mountain Sickness)

Use the 'buddy system', because you will most likely refuse to acknowledge your own symptoms of altitude sickness. It is not unusual for affected climbers to stubbornly refuse to descend.

If one of your party is showing the signs of altitude sickness, first aid suggestions include:
  • Don't climb any higher. Camp and wait until the symptoms subside. This can take a couple of days.
  • Make sure they avoid alcohol and cigarettes.
  • Give them aspirin or paracetamol in the usual recommended doses.
  • Encourage them to breathe deeply every few minutes to decrease the level of carbon dioxide in their blood.
  • Give them the recommended doses of the drug dexamethasone.
  • In severe cases of altitude sickness, descend immediately. Aim for a descent of around 500 m to 1,000 m.
  • Give them diuretic drugs (which promote urine production) to reduce the risk of fluid accumulation.
  • Administer oxygen from a portable oxygen cylinder.

Altitude Sickness (Mountain Sickness) Prognosis

The prognosis for acute altitude sickness is excellent as long as common sense is used. Descending, delaying further ascent, rest, and paying attention to the body's symptoms are usually all that is necessary to ensure a complete recovery.

High altitude pulmonary edema (HAPE) has a good outcome if symptoms are recognized and treated early. If descent is impossible or if hyperbaric therapy, supplemental oxygen, and access to medical care are not available, HAPE can progress to respiratory failure and ultimately to death. Remember that HAPE is the number one cause of death from high altitude illness.

More than half of people with HACE who develop coma die. Of those who survive, mental impairment and coordination defects may continue to affect them. HACE can be fatal if not recognized and treated quickly.

Things to remember

Mountain climbers are at risk of developing altitude sickness.

Altitude sickness is caused by ascending too rapidly, which doesn't allow the body enough time to adjust to reduced oxygen and changes in air pressure.

Symptoms include headache, vomiting, insomnia and reduced performance and coordination.

In severe cases, fluid can build up within the lungs, brain or both, which can be fatal.

First aid options include descending immediately, medications and the use of oxygen administered from a portable container.