What is HAPE? How people in the mountains can still fall ill to this type of altitude sickness

Dr. Ebert-Santos hopes to continue her research and make others aware of high altitude pulmonary edema

Cody Jones
Summit Daily News
Storm clouds roll over Loveland Ski area and the Continental Divide from a vantage point near Loveland Pass on Sunday, May 7, 2023. When visiting high-elevation areas, people from lower elevations can fall ill to high altitude pulmonary edema, which can be fatal if left untreated for too long.
Andrew Maciejewski/Summit Daily News

Many people are familiar with altitude sickness and the effect it has on the body, but many people often fail to realize that there is a severe form of altitude sickness that even people living at higher elevations can fall ill to.

High altitude pulmonary edema — commonly referred to as HAPE — is a more serious case of altitude sickness that, if not treated quickly or properly, can lead to death.

Due to the cases she has seen at Frisco’s Ebert Family Clinic over the past several years, Dr. Christine Ebert-Santos has been working diligently to make the medical and mountain community aware of the risks of high altitude pulmonary edema.

According to Ebert-Santos, one of the reasons why high altitude pulmonary edema is such a risk to people living in or visiting mountain communities is that oftentimes it can be misdiagnosed for asthma or pneumonia.

“That is what we are taught in medical school,” Ebert-Santos said. “We are not taught about high altitude pulmonary edema, we are taught about pneumonia. When they get the X-ray of the kid that is sick with pulmonary symptoms they will call it pneumonia and put him on antibiotics.”  

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One of the major reasons why it’s often misdiagnosed by doctors is that many of its main symptoms double for symptoms of other conditions like asthma or pneumonia. 

“The first sign is usually a cough,” Ebert-Santos said. “Followed by shortness of breath with any effort — even just walking — and fatigue. You just want to lie on the couch.”

If left untreated, the early warning signs of high altitude pulmonary edema can rapidly progress into having fluid build up in the lungs, which will then lead to a patient’s oxygen saturation levels rapidly decreasing. If the individual does not seek treatment quickly, the condition can be fatal.

“There are deaths usually every couple of years in adults who come to ski or have a vacation with their friends,” Ebert-Santos said. “There are so many times when people are sick with a virus and you don’t really give it a second thought. Without having somebody’s eyes on you or having a pulse oximeter to see what is happening with your oxygen, you can’t really know if this is something going on in your lungs or it’s just a cold.”

As they are acclimated to high elevations, mountain residents may think that they are immune to the condition, but research from doctors like Ebert-Santos has shown that residents and visitors alike can be affected by high altitude pulmonary edema.

A headshot of Dr. Christine Ebert-Santos outside of the Ebert Family Clinic in Frisco. Ebert-Santos is on the frontline of researching and educating the public on the prevalence of high altitude pulmonary edema in mountain communities.
Christine Ebert-Santos/Courtesy photo

There are currently four known forms of high altitude pulmonary edema, including classic, reentry resident and highlanders. Classic is the most typical form, occurring with people living at lower elevations visiting a high elevation location. Reentry occurs when a high-elevation resident goes to a lower elevation and returns to a higher elevation. Resident occurs to an individual living at a high elevation without changing their elevation. Highlanders occurs in individuals who live at a high elevation, but then travel to a higher elevation.

One of the most extreme cases of highlanders Ebert-Santos has witnessed occurred when Summit County resident Jonathan Huffman attempted to hike Mount Kilimanjaro.

Since Huffman lived at a high elevation and was physically fit, he did not think he would be at risk for developing a form of high altitude pulmonary edema, but the extreme change in elevation ultimately led to Huffman starting to feel sick.

With a feeling of fluid building up in his lungs and feeling like he was slowly drowning, his blood-oxygen levels plummeted to 67% while he sat all night propped up on duffle bags or in a chair.

Luckily the team members around Huffman were able to recognize the symptoms of highlanders and were able to give him oxygen treatments and transport him to a lower elevation where he eventually made a full recovery. 

Highlanders and reentry high altitude pulmonary edema are the most common cases that Ebert-Santos sees in her youth patients at her practice in Frisco. Many mountain families travel to sea level for vacations, but when the families return the kids can often develop a cough or sound congested. 

“Parents would call me and say that my child sounds really congested,” Ebert-Santos said. “That would ring a bell in my head because the sound of fluid in your lungs and nasal conjunction overlaps. I cannot expect a non-medical person without a stethoscope and a pulse oximeter to be able to differentiate between a kid who has a cold and a kid who has an impending critical condition that could kill them.”

With reentry and highlanders affecting children every year, Ebert-Santos recommends that every family has a pulse oximeter handy in case anyone in the family starts to feel the symptoms associated with the medical condition.

Even if a family feels like their child has a cold, Ebert-Santos recommends using a pulse oximeter, as a common cold or a strain of influenza can make kids more susceptible to developing a form of high altitude pulmonary edema.

If a patient’s oxygen saturation level is below 90%, it could potentially be a case of high altitude pulmonary edema and individuals should head to the emergency room to be fully assessed. If a medical professional believes a patient does indeed have the condition, they will then put them on oxygen and will typically transport them from a higher elevation to a lower elevation to recover.

From what Ebert-Santos has seen in her research thus far, she believes that the condition is more prevalent in youth, but is hoping to find more cases like Huffman where adults have been diagnosed with high altitude pulmonary edema.

Ultimately, Ebert-Santos is hoping to spread the message that visitors and residents can both be diagnosed with high altitude pulmonary edema. 

“It is not in the literature yet,” Ebert-Santos said. “People who live here get HAPE. Everyone thinks that if you live here that you are not susceptible to mountain sickness and HAPE. That is the fallacy that we have to reverse with education.”

Ebert-Santos will further her current research by reviewing cases of children under the age of 18 who may have been misdiagnosed with pneumonia or asthma when in reality they perhaps had a form of high altitude pulmonary edema. 

Those interested in staying up to date with Ebert-Santos’ high altitude pulmonary edema research, can visit her blog at

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