Category Archives: Health

Return to High Altitude after Recovery from Coronavirus Disease 2019

Andrew M. Luks and Colin K. Grissom

https://www.colorado.com/activities/colorado-hiking

Prior to COVID-19, I would hike the beautiful mountains of Colorado known as 14ers, a name given to these mountains for being over 14,000 ft. I, like most high-altitude travelers faced the more common concerns associated with hiking such as acute mountain sickness (AMS), high altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE). With the increase in high-altitude travel, I wondered if there are any new precautions that we should consider before resuming the activities that we love.

The purpose of this article is to highlight the recommendations for patients who wish to return to high-altitude travel after a COVID infection. Not everyone needs an evaluation after a COVID infection. The recommendations noted in this article are based on the duration and severity of the illness of each individual person.

So, who should receive an evaluation before high-altitude travel?

  1. Individuals with symptoms after 2 weeks of a positive COVID-19 test without hospitalization,
  2. Individuals with symptoms after 2 weeks after hospital discharge,
  3. Anyone who required care in the intensive care unit (ICU), and
  4. Anyone who developed myocarditis or thromboembolic events. The recommendations are to undergo pulse oximetry at rest and with activity, spirometry, lung volumes, and diffusion capacity for carbon monoxide(DLCO), chest imaging, electrocardiography (EKG), B-type natriuretic peptide, high sensitivity cardiac troponin (hsTn), and echocardiography.

It is expected that people with lower oxygen levels (hypoxemia) at rest or with exertion in lower elevations will experience greater hypoxemia with ascent to high altitude. It has been shown that ascent to high altitude causes a decrease in barometric pressure leading to a decrease in ambient and inspired partial pressure of oxygen. The decrease in partial pressure of oxygen in alveoli (PaO2) will trigger vasoconstriction of pulmonary arterioles that slows the rate of oxygen diffusion and activates chemoreceptors that increase minute ventilation from hypoxia. However, it is still unclear whether people with low oxygen levels at low elevations are at greater risk for acute altitude illness after ascent. The recommendation is to monitor pulse oximetry after arrival of high altitude.

Individuals with abnormal lung function tests don’t have to avoid high altitude travel as previous studies have shown that patients with COPD with abnormal lung functions tolerate exposure. Furthermore, in people with mild to severe COVID-19 symptoms, the lung mechanic markers such as forced expiratory volume (FEV1), forced vital capacity (FVC) and total lung capacity (TLC) normalize in up to 150 days of infection.  However, if individuals have severe limitations with exercise capacity, they should monitor their oxygen levels with pulse oximetry after ascent. Reduction in exercise capacity is possible after COVID infection and depends on the severity of the illness. Blokland et al., 2020 has shown that previously intubated individuals had a median VO2 max of 15ml/kg per min (average male 35 to 40 and average female 27 and 30), roughly 57% predicted immediately after hospitalization. 

In acute hypoxia, the heart rate increases, which leads to an increase in cardiac output. Individuals with reduced ventricular function from COVID infection do not have to avoid travel. Previous research has shown that individuals with heart failure can tolerate exercise with hypoxia. Moreover, data has shown that individuals with COVID infection maintain preserved left ventricular function and only 3% show a reduced ejection fraction. Individuals with abnormal EKG rhythms and ischemia should be referred to cardiology.  If high sensitivity troponin was abnormally elevated, this would require evaluation for myocarditis with a cardiac MRI. Knight et al., (2020), found that 45% of patients with unexplained elevations of high-sensitivity troponin were found to have myocarditis during hospitalization. It is still unclear how long these abnormalities will last and how it will affect people.

 A concerning finding on ECHO is pulmonary hypertension, as previous research has shown an increased risk in developing HAPE. A study reported that 10% of patients hospitalized for COVID without mechanical ventilation had right ventricular dysfunction for over 2 months. Several studies reported that 7-10% of individuals may have pulmonary hypertension after COVID infection. A vasodilating drug such as nifedipine can be given prophylactically if pulmonary hypertension is unrelated to left heart dysfunction but nifedipine can worsen hypoxemia.

The recommendation for patients who developed myocarditis from a COVID infection is to have an ECHO, Holter monitor, and exercise EKG 3-6 months after illness. Travel can resume after a normal ECHO, no arrhythmias on exercise EKG, and after inflammatory markers (ESR and/or CRP) have normalized. Previous studies suspected that areas with low atmospheric pressures (e.g., high-altitude) that induce hypoxia have increased risk for clot formation. However, this suspicion has never been firmly established; therefore there is no reason to believe that high-altitude will increase the risk for clot formation in individuals who developed an arterial or venous clot from COVID infection.

A few things to consider before planning a high-altitude excursion includes planning to visit areas with access to medical resources or the ability to descend rapidly. If you are new to high altitude, it is recommended to slow the ascent rate. Traveling to high elevations (>4000m) should be avoided until tolerance has developed with moderate elevations (2000-3000m). A more gradual return to physical activity at high altitude is recommended rather than immediate resumption of heavy exertion. As the pandemic subsides and with increase in mountain travel, more research will develop that can better address these risks.

Good news! The Ebert Family Clinic in Frisco, CO provides pulse oximeters for free. So, make sure to visit and grab your pulse oximeter before your next ascent.

Quick Summary of Recommendations

Individuals who require evaluation prior to high-altitude travel:

  1. Individuals who have symptoms after 2 weeks of a positive COVID-19 test without hospitalization
  2. Individuals who have symptoms after 2 weeks after hospital discharge
  3. Any patient who required care in the intensive care unit (ICU)
  4. Any patient who developed myocarditis or thromboembolic events

General recommendations for anyone before high-altitude travel:

  1. Monitor pulse oximetry after arrival of high altitude, and access care or descend if symptoms worsen.
  2. Rest and avoid high-altitude travel for at least 2 weeks after a positive test, and consider a gradually return to physical activity at higher altitudes.
  3. All individuals planning high-altitude travel should be counseled on how to recognize, prevent, and treat the primary forms of acute altitude illness (AMS, HACE, and HAPE)
  4. Limit the extent of planned exertion after ascent and, instead, engage in graded increases in activity that allow the individual to assess performance and avoid overextending themselves.

Reasons to forgo high-altitude travel:

  1. Severely elevated pulmonary artery pressures may be a reason to forego high-altitude travel altogether.
  2. High-altitude travel should likely be avoided while active inflammation is present in myocarditis.
  3. Patients who experienced arterial thromboembolic events due to COVID-19, (e.g. myocardial infarction or stroke) should defer return to high altitude for several months after that event or any associated revascularization procedures.

References:

  1. Andrew M. Luks and Colin K. Grissom. Return to High Altitude After Recovery from Coronavirus Disease 2019. High Altitude Medicine & Biology. http://doi.org/10.1089/ham.2021.0049
  2. Christensen CC, Ryg M, Refvem OK, Skjønsberg OH. Development of severe hypoxaemia in chronic obstructive pulmonary disease patients at 2,438 m (8,000 ft) altitude. Eur Respir J. 2000 Apr;15(4):635-9. doi: 10.1183/09031936.00.15463500. PMID: 10780752.
  3. Blokland IJ, Ilbrink S, Houdijk H, Dijkstra JW, van Bennekom CAM, Fickert R, de Lijster R, Groot FP. Inspanningscapaciteit na beademing vanwege covid-19 [Exercise capacity after mechanical ventilation because of COVID-19: Cardiopulmonary exercise tests in clinical rehabilitation]. Ned Tijdschr Geneeskd. 2020 Oct 29;164:D5253. Dutch. PMID: 33331718.
Image of Jesse Santana, dark brown hair, brown skin, beard and moustache with a stethoscope draped over his white coat, striped, collared shirt and maroon tie.

Jesse Santana is a second-year PA student at Red Rocks Community College in Denver, Colorado. He grew up in Colorado Springs, CO and attended the University of Colorado-Colorado Springs where he earned a bachelor’s in Biology and Psychology. Jesse worked as a Certified Nursing Assistant for two years before pursuing a Master’s in Biomedical Sciences at Regis University in Denver. Shortly after, he coordinated clinical trials in endocrinology and weight loss as a Clinical Research Coordinator at University of Colorado Anschutz Medical Campus. He enjoys hiking Colorado’s 14ers, spending time with family and friends, and camping.

Maternal Intermittent Hypoxia and the Effect on Adult Respiratory Control and the Gut Microbiome in Male Offspring

On Friday, June 4th, I had the pleasure of attending the, online, Fifth Annual Center for Physiological Genomics of Low Oxygen (CPLGO) Summit. There were many great presentations that I had the opportunity to watch, including the presentation of Dr. Christine Ebert-Santos’ study looking at nighttime pulse oximetry in participants living at high altitude for longer than one year. The presentation this post will discuss is about research conducted at the University of Florida by Dr. Tracy Baker, PhD. This presentation was particularly of interest because it looks at hypoxia in relationship to Obstructive Sleep Apnea (OSA). OSA occurs when patency of the upper airway is compromised and air is inhibited from passing, leading to hypopnea and obstructive apneas1. Hypopnea are episodes of greater than 30% decrease in air flow that lasts ≥ 10 seconds with continued respiratory effort1. Obstructive apnea is a total stop in airflow that lasts ≥ 10 seconds with chest and abdominal efforts to continue breathing1. Patients with OSA have a higher apnea-hypopnea index (AHI) at altitude than at sea level, meaning that their time with decreased oxygenation while sleeping is increased at higher altitude2. Additionally, patients living at altitude with mild or moderate sleep apnea may have a false negative sleep apnea result when having a sleep study performed at sea level, which means that patients who have OSA at altitude will not show signs of sleep apnea at sea level, therefore missing the diagnosis on sleep study2.

Currently, it is understood that the effects of hypoxia secondary to sleep apnea takes a toll on the body over time. Patients often experience snoring and daytime sleepiness in addition to other symptoms or changes to the body that may not be as easily recognizable, such as living in an increased inflammatory state1,3. Further, it is well known that an adverse maternal environment during pregnancy can lead to long term fetal complications3. Combining these two concepts, Dr. Baker wanted to further investigate the adverse effects of hypoxia due to maternal sleep apnea to get a better understanding of the subsequent consequences this deprived oxygen state has on mothers and their offspring. The hypothesis of this study was: Intermittent hypoxia during pregnancy has detrimental and long-lasting consequences on offspring neural function.

To test this hypothesis, Dr. Baker and her team exposed pregnant rats to intermittent hypoxia during days 10-21 of gestation. OSA was modeled from hypoxia episodes, but not the sleep fragmentation that accompanies the disease. It is understood that both components of sleep apnea, hypoxia and sleep fragmentation, would have their own influence on the offspring. The rats were put into a chamber and delivered 15 episodes of hypoxia per hour, as people can experience up to 10-20 episodes of apnea per hour during pregnancy, in increments of 90 seconds with 90 seconds of normoxia in between. During hypoxic episodes, oxygen levels were brought down to 10% and oxygen saturation was reliably reduced to 85% with adequate re-saturation during episodes of normoxia. Control rats were exposed to normoxia, 21% oxygen “on and off”, to control for and take into consideration confounding factors such as air flow within the chamber. While in labor, the rats were then removed from the chamber to give birth in a normal environment. The baby rats, or pups, were never exposed to hypoxia after they were born. Lastly, the pups were followed into adulthood to monitor for long term effects.3

Next, data from the gestational induced hypoxia (GIH) offspring and the control rat offspring (GNX) was compared. The GIH offspring showed no evidence for obesity and no difference in the volume of fat pads from shortly after birth to 12 weeks, as they had the same trajectory as the GNX offspring. There was also no difference between gestational length, number of pups, pup retrieval time, or pup survival between the two groups. To evaluate effects of gestational hypoxia on breathing, the adult offspring were placed in a plethysmography chamber. A plethysmography chamber measures changes in volume in the body to assess how much air is in the lungs when breathing. The rats were given one-hour to acclimate in the chamber and ventilation was then measured over the following three hours. Of the two groups, male GIH offspring had a significantly increased number of spontaneous apneas per hour compared to male and female GNX offspring and female GIH offspring, who had no change in the number of apneic episodes. Apneic episodes are defined as a pause in breathing that lasts longer than the duration of two breaths. Spontaneous apneic episodes are episodes of apnea with no apparent trigger on plethysmography signal. Approximately 60% of GIH male offspring had spontaneous apnea out of the 95% confidence interval, suggesting gestational intermittent hypoxia altered the phenotype in the male offspring. Again, this was not a congruent finding in GIH females.3

An additional factor to be considered in this scenario is respiratory plasticity, which is the body’s ability to help animals adapt to life changing circumstances, such as hypoxia and sleep apnea. A body’s ability to have respiratory plasticity is suggestive of a healthy neural system because breathing is an automatic and rhythmic function of the brain stem. Ultimately, the respiratory system you are born with is not the one you will die with. Recurrent central apnea can promote respiratory plasticity. Dr. Baker’s team further investigated whether the GIH rats had an altered adaptive response to conditions that alter the body’s natural response to breathing, which in this case is recurrent central apnea. Her team mechanically ventilated adult offspring that were vagalized, paralyzed, and urethane anesthetized to study neural control of breathing independent from the process of ventilation, and data was recorded via phrenic neurograms. A neural apnea was caused by lowering PaCO2 levels lower than the level for breathing and was then stopped by raising PaCO2 back to baseline levels. Recurrent neural apneas triggered plasticity mechanisms to make it harder to elicit the next apnea. Data showed adult male GIH offspring have impaired responses to recurrent reductions in respiratory neural activity and did not express plasticity following a triggered central apnea episode. Like prior results, female GIH offspring did not have this same neural plasticity impairment as the males, showing no elevations in spontaneous apnea and intact compensatory plasticity triggered by central apneas.3

Further, adult offspring were assessed for increased inflammation. To no surprise, GIH males had increased basal neuroinflammation. Although both male and female GIH offspring had increased inflammatory markers, the females were able to suppress the inflammation by an unknown mechanism that the male GIH offspring could not. Adult offspring of GIH and GNX groups were exposed to bacterial lipopolysaccharide (LPS), which confirmed that the GIH males mounted a greater inflammatory response compared to the other offspring, suggesting these males have an altered inflammation response. In the central nervous system (CNS), microglia are innate immune cells that can produce inflammatory cytokines and comprise 5-10% of CNS cells. Dr. Baker’s team pharmacologically depleted these cells in the adult offspring by administering the drug PLX3397 for seven days. This resulted in a stark reduction of microglia by 86%. The GIH male offspring with depleted microglia were able to regain compensatory plasticity triggered by recurrent central apneas. Three days after stopping PX3397, the microglia came back and expanded. When the microglia repopulated, there was restoration of the impaired plasticity phenotype in GIH males.3

To get a better understanding of what could be driving the persistent microglial inflammation in the GIH males, the gut-brain-axis was assessed. In human literature, it is suggested that sleep apnea is associated with gut dysbiosis. Investigating this link, feces was collected from the rats which showed diversity in the bacterial species present in GIH males compared to GIH females and both sexes of the GNX group. Dr. Mangalam looked at the GI bacteria shift and determined the gut microbiomes were comprised of two main phyla of bacteria, Bacteroidetes and Firmicutes. GIH males had increased Bacteroidetes and decreased Firmicutes compared to the other offspring. Initially unsure of this significance, Dr. Mangalam deduced that the decreased bacteria in the GIH male microbiome produce a short string fatty acid called butyrate. Once produced, this fatty acid stimulates the release of neuropeptides and serotonin, which are up taken by the portal vein. From there, butyrate enters the blood circulation and crosses the blood brain barrier (BBB), stimulating active receptors on the vagus nerve. Butyrate supports plasticity in the brain and reduces inflammation.3

This leads to the final question: can the neural plasticity deficit be rescued by decreasing neuroinflammation by supplementing male GIH offspring with butyrate? GIH male rats were supplemented with eight doses of 2mg/kg of Tributyrin over 22 days, which is converted into butyrate3. Upon creating central apnea in the GIH males treated with Tributyrin, it was found that their respiratory plasticity was fully rescued3. So, what does this mean?

Simply, this means gestational intermittent hypoxia has sex-specific, long-lasting effects on adult offspring physiology. This is shown by: 1) gut dysbiosis in male offspring, 2) increased central apneas during sleep with impaired respiratory plasticity, 3) enhanced basal inflammation of microglia in male offspring with increased inflammatory response upon provocation, and 4) microglial depletion or butyrate supplementation repaired deficits in respiratory plasticity.3

The research conducted by Dr. Baker’s team opens additional research opportunities regarding effects of hypoxia on vulnerable populations, such as pregnant mothers and their offspring. The findings from this study can be retested and built upon as research continues to be done. Although this research was not conducted at altitude, it is still interesting and pertinent to the altitude community, as hypoxia and OSA are common problems at altitude. This study contributes important knowledge to the science and medical community; however, more research will need to be done to confirm and fully understand the adverse effects of hypoxia during pregnancy. Further, more information is needed to understand how effects of gestational hypoxia can be applied to populations experiencing hypoxia secondary to living at altitude in a low oxygen environment.

References:

  1. Guilleminault C, Zupancic M. Sleep Disorders Medicine. Third Edition. Philadelphia, PA. Saunders. 2017. pp: 319-339.
  2. Patz D, Spoon M, Corbin R, et al. The effect of altitude descent on obstructive sleep apnea. CHEST. 2006; 130(6): 1744-1750. Doi: https://doi.org/10.1378/chest.130.6.1744
  3. Baker T. CoBAD: Maternal Intermittent Hypoxia and the Effect on Adult Respiratory Control and the Gut Microbiome in Male Offspring. Oral presentation at: the Fifth Annual Center for Physiological Genomics of Low Oxygen (CPLGO) Summit; June 4th, 2021; online.

Amanda Smith is a second year PA student at Drexel University in Philadelphia, Pennsylvania. Amanda was raised in the “sweetest place on Earth”, Hershey, Pennsylvania. She obtained her B.S. in Health Science with a double minor in Creative Writing and Community Health at Hofstra University on Long Island. Between obtaining her undergraduate and graduate degrees, Amanda worked as an Emergency Department scribe, pediatric nurse aide, and as a lead research coordinator in Neurosurgery/Neuro-Oncology at the Penn State Hershey Neuroscience Institute. Amanda loves to travel and was able to incorporate her love for traveling and medicine by traveling across the country for clinical rotations, rotating at sites in New York, California, Pennsylvania, and Colorado, with her next destination in Alaska!

Anxiety at Altitude

As I arrived in Denver (5280′), and ultimately Frisco, CO (9000′), the first physical symptom I noticed from the high-altitude environment was dyspnea on exertion. On flat ground I didn’t feel any different than at home in New Jersey, but as soon as I began to climb stairs or hike the beautiful trails in the area, I quickly became winded. I had already read about the common symptoms of high-altitude acclimation and knew this was normal and was on the lookout for headache, nausea, or dizziness. I noticed my resting heart rate was elevated and told myself this was also normal because the low-oxygen environment required my heart to work harder to keep my pulse oxygen levels up. I already owned a pulse oximeter that I had bought during my time working with COVID patients in the Emergency Room on a previous rotation. I checked that within my first week and was initially disappointed that it was averaging around 91%, but soon found out this was also normal, especially since I was still acclimating. My Apple watch trended data over time on my heart rate and I noticed a tremendous difference in my resting HR compared to home.

I landed on May 2nd, 2021 and I think the graphs above make that quite evident. My walking HR was even more noticeably elevated. “The initial cardiovascular response to altitude is characterized by an increase in cardiac output with tachycardia … after a few days of acclimatization, cardiac output returns to normal, but heart rate remains increased”1

My persistently elevated heart rate caused me to feel anxious when hiking or doing other physical activity, and that anxiety in turn raised my heart rate even more. I had experienced PVC’s in the past which occurred only a few times a month, nowhere near the threshold for treatment, and had been reassured they were totally benign. On a hike during my first week in Colorado I experienced a few of these “skipped beats” followed by rapid heart rate and had to talk myself down from the anxiety it caused. This is what prompted me to research the effect of altitude on anxiety. “Adrenergic centers in the medulla are activated in acute hypoxia and augment the adrenergic drive to the organs.”2 It seems as though the body’s compensatory mechanisms to physiological changes can be accompanied by unwanted mental health disturbances. This is especially true for people in the early stages of shifting from low altitude to high altitude. During the adjustment period individuals are most susceptible to new-onset anxiety disorders, but even those living long-term at high altitude are at increased risk of psychiatric ailments.4 In fact, living in high-altitude environments has been associated with serious mental health implications not limited to anxiety disorders, including depression and increased suicidality.4 This has been evidenced by statistically significant changes in PHQ-9 Total Score, PHQ-9 suicidal ideation, and GAD-7 Total Score.4

Sleep disturbances have often been faulted for these increases in anxiety and depression at high altitude, and although I didn’t have any formal sleep studies done while in Colorado, I felt well-rested and didn’t notice a change in my sleep at altitude.3 One hypothesis that could explain these findings and my personal experience, is that hypoxia has an inverse relationship with serotonin.4 Because oxygen is a requirement for the creation of serotonin, living somewhere with decreased oxygen could lead to deficiency. Serotonin has an expansive role in the human body, playing a role in cognition, sleep, mood, digestion and other crucial aspects of life. Low levels of this neurotransmitter have been implicated as a cause for depression and accordingly many of our best antidepressant medications like SSRI’s and SNRI’s work on these pathways. There is also a “chicken or the egg?” argument to be made. Is the anxiety brought on due to hypoxia which in turn causes somatic symptoms like palpitations, shortness of breath, and presyncope; or do these symptoms caused by hypoxia come first, resulting in anxiety and panic attacks? For example, hyperventilation, a well-known provocative factor of panic attacks, is also a response to altitude changes. Hypoxia leads to hypocapnia, which can ultimately lead to respiratory alkalosis.5 Although there are multiple hypotheses for these mental health changes, there does seem to be an agreement in the literature that they do exist.

Luckily, in my experience, my body adjusted over the span of a few weeks. My HR began to trend down towards my normal resting rate in the 70’s and my anxiety levels also dropped. I started doing more challenging hikes, traveling and enjoying the many natural wonders Colorado has to offer. Just being in amazing places like Rocky Mountain National Park and the San Isabel National Forest had a profound impact on my mood as I soaked in the scenery. I took pictures, breathed fresh mountain air and spotted wildlife, which all served to distract me from my worries. The mood-altering benefits of exercise also likely played a role in my increasing happiness. I grew to love the state and as soon as I felt fully adjusted, it was time to go back to New Jersey. Back to sea-level, outrageous humidity and hotter weather.

References:

  1. Naeije R. Physiological adaptation of the cardiovascular system to high altitude. Prog Cardiovasc Dis. 2010 May-Jun;52(6):456-66. doi: 10.1016/j.pcad.2010.03.004. PMID: 20417339.
  2. Richalet JP. Physiological and Clinical Implications of Adrenergic Pathways at High Altitude. Adv Exp Med Biol. 2016;903:343-56. doi: 10.1007/978-1-4899-7678-9_23. PMID: 27343107.
  3. Bian SZ, Zhang L, Jin J, Zhang JH, Li QN, Yu J, Chen JF, Yu SY, Zhao XH, Qin J, Huang L. The onset of sleep disturbances and their associations with anxiety after acute high-altitude exposure at 3700 m. Transl Psychiatry. 2019 Jul 22;9(1):175. doi: 10.1038/s41398-019-0510-x. PMID: 31332159; PMCID: PMC6646382.
  4. Kious BM, Bakian A, Zhao J, Mickey B, Guille C, Renshaw P, Sen S. Altitude and risk of depression and anxiety: findings from the intern health study. Int Rev Psychiatry. 2019 Nov-Dec;31(7-8):637-645. doi: 10.1080/09540261.2019.1586324. Epub 2019 May 14. PMID: 31084447.
  5. Roth WT, Gomolla A, Meuret AE, Alpers GW, Handke EM, Wilhelm FH. High altitudes, anxiety, and panic attacks: is there a relationship? Depress Anxiety. 2002;16(2):51-8. doi: 10.1002/da.10059. PMID: 12219335.

Joseph Albanese is a second-year physician associate (PA) student attending Drexel University in Philadelphia, Pennsylvania. He grew up in Hillsborough, NJ. He got his BA from The Pennsylvania State University as a double major in Psychology and Film Studies. Prior to PA school he worked as a mental health associate in an inpatient psychiatry setting with actively suicidal and homicidal patients. The acuity of the unit he worked on made him appreciate the benefits of talk-therapy, but also the crucial role of medicine in many cases. This led him to apply to PA school. In his free time Joe loves to travel (favorite places include Japan, Iceland, Glacier National Park, and now Colorado). He also enjoys photography, playing sports, and eating new foods.

Nail Abnormalities at High Altitude

With summer just around the corner, more people will be hitting the mountains for some high altitude hikes and 14ers. There have been numerous anecdotal findings of mountaineers with changes to their fingernails after ascending the world’s tallest peaks, with the most common abnormalities being Mees’ lines, Muehrcke’s lines, and Beau’s lines. While the peaks in Colorado do not compare to those of the Himalayas, there is always a chance, albeit very low, that you may notice some changes to your nails after a high altitude expedition.

Both Mees’ lines and Muehrcke’s lines are types of leukonychia, which means “white nails”. Mees’ lines present as a single horizontal white band, sometimes multiple, located in the nail plate and are non-blanching. Throughout history, Mees’ lines have been associated with drug toxicity, such as from arsenic or thallium.4 Additionally, there are many systemic diseases that have been associated with Mees’ lines in which the body is experiencing high amounts of stress, such as with myocardial infarction, sickle cell crisis, and tuberculosis.4

Mee’s lines

One case report, “Mees’ lines in high altitude mountaineering”,  by Avinash Aujayeb details how a 27-year old man developed Mees’ lines after he traversed high altitudes in the Pakistani Karakorum range, attempting to scale a summit of 7031 meters.1 He acclimated to altitude at a camp located at 4000 meters,  and stayed for a total of 21 days. No medications were used for acclimatization. In his attempt to reach the summit, he became extremely fatigued and hypothermic, and turned around at 6900 meters. Upon return to sea level, he lost about 17 pounds of weight. Six weeks after his expedition, he developed non-blanching horizontal white lines on his nails, consistent with Mees’ lines. The lines eventually moved distally and completely disappeared. While the paper does not go on to hypothesize the cause of this man’s development of Mees’ lines, it seems reasonable that they appeared due to the stress the man endured as evidenced by his need to turn around early from fatigue and hypothermia, and likely hypoxia given the extreme altitude.

Muehrcke’s lines present as a pair of horizontal white bands located in the nailbed, the skin beneath the nail plate, making them blanchable (unlike Mee’s lines which are located within the nail itself). Muehrcke’s lines usually present on the 2nd, 3rd and 4th fingers, and typically spare the thumb. Historically, these lines are most associated with hypoalbuminemia as seen in a protein-losing condition of the kidney called nephrotic syndrome.4 They have also been found in disease states of systemic immunosuppression, such as in HIV, where the metabolism of the body is stressed and has decreased ability to make proteins. 4

Muehrcke’s lines

The discovery of Muehrcke’s lines was first published in the British Medical Journal in 1956 by Robert C. Muehrcke.4  In the paper, he details a study in which he compared 750 adult patients and healthy volunteers who had normal serum albumin against 65 patients known to have chronic hypoalbuminemia.  He saw that the pair of white horizontal lines were only in those with the chronic hypoalbuminemia, most specifically those with a serum albumin below 2.2 g/dL.4 Once these patients were treated and their albumin concentrations increased, the lines disappeared after a few weeks. He thought the findings suggested that Muehrcke’s lines were from an albumin deficiency due to poor nutrition.

In a letter to the editor of High Altitude Medicine and Biology, authors Windsor, Hart, and Rodway describe the presence of Muehrcke’s lines on Mount Everest after a 38 year old with no significant medical history noticed their appearance a few weeks after he had returned to sea level.3 There were two parallel horizontal lines under the nails of his 2nd, 3rd, 4th, and 5th digits, sparing the overlying nail. They believe the development of these nail findings were indeed from hypoalbuminemia , however do not believe it was from a nutritional deficiency as Muehrcke first described, because the climber had been healthy throughout his expedition and he maintained good nutrition.3 They attribute the findings to peripheral edema, which is a common finding in high altitude mountaineers. With this edema, fluid levels in the tissues increase. The authors believe this may have inhibited the growth of the nailbed, which then resumed with return to sea level.

Another nail finding from high altitude mountaineering is called Beau’s lines, which are an indented groove across the span of the nail horizontally, beginning at the base of the lunula. The lines result when nail formation is temporarily halted during episodes of stress, and usually present several weeks after the stressful incident.2 They are generally caused by local trauma to the nail, extreme temperatures, and toxicity from chemotherapy.4

Beau’s lines

There was a prospective study completed by authors Bellis and Nickol in High Altitude Medicine and Biology where the study participants were completing a research expedition in eastern Nepal in April and May of 2003.2 The maximum altitude reached varied from 5,142 to 6,476 meters and the length of stay of each individual also varied. The study found Beau’s lines developed in 1 out of 56 participants at 4 weeks, however by 8 weeks, 17 out of the 52 (or 33%) developed Beau’s lines. The authors hypothesized that the changes were possibly due to the hypoxic as well as hypobaric environment which could diminish the activity of the nail matrix. However, they did acknowledge the fact that there were other factors that could have resulted in the Beau’s lines, such as extreme cold conditions and possible injuries to the fingers due to the nature of the work of the researchers. No participants reported frostbite or any damage to the hand, however at night temperatures dropped as low as negative 20 degrees Celsius.

Clubbed fingers

These nail abnormaltities are less likely to be found during expeditions within the United States unless hiking in Alaska, which has Denali, the tallest peak in the US at 20,310 meters. Outside of Alaska, the tallest peak is Mount Whitney in California, which pales in comparison at 14,505 meters. Most of the case reports completed on these nail findings were from several week-long expeditions in the Himalayas. However, condition you may already be aware of is clubbing of the fingers. This presents as a bulbous enlargement of the fingertips caused by chronic hypoxia. During my five-week visit here, I have anecdotally heard from two different Summit County residents that they have many healthy and young friends with clubbed fingers. Unfortunately, I was unable to find any research on the prevalence of clubbed fingers among individuals living at high elevations, but I believe it is something that deserves to be looked into deeper. 

References

  1. Aujayeb, A. (2019). Mees’ lines in high altitude mountaineering. BMJ Case Reports, 12(3), 1. doi:10.1136/bcr-2019-229644
  • Bellis, F., & Nickol, A. (2005). Everest Nails: A prospective study on the incidence OF Beau’s lines after time spent at high altitude. High Altitude Medicine & Biology, 6(2), 178-180. doi:10.1089/ham.2005.6.178
  • Windsor, J. S., Hart, N., & Rodway, G. W. (2009). Muehrcke’s lines on Mt. Everest. High Altitude Medicine & Biology,10(1), 87-88. doi:10.1089/ham.2008.1079
  • Zaiac, M. N., & Walker, A. (2013). Nail abnormalities associated with systemic pathologies. Clinics in Dermatology,31(5), 627-649. doi:10.1016/j.clindermatol.2013.06.018

Makenna Schmidgall is a second-year physician assistant student at the Midwestern University Physician Assistant Program in Glendale, Arizona. She grew up in Gilbert, AZ, but left her desert home to attend New York University in the Big Apple where she earned a bachelor’s degree in Global Public Health/Biology. During her junior year of college, she began working as an ER scribe in multiple emergency departments of the Mount Sinai Health System in New York, NY. She enjoys gardening, hiking and playing with her new Labrador retriever puppy “Piper”.  

HAST: the High Altitude Simulation Test

Maybe you are planning to ski or hike a 14er. Taking a leap of faith and moving out of the city and into the mountains. Or maybe it’s just taking a flight in a pressurized airplane cabin. Maybe you just spent 10 days in the hospital with rib fractures and are now anxious to return home to 9000 feet in elevation. You could be an individual that is worried you will miss out on that incredible work retreat to a beautiful mountain sanctuary due to your apprehension about your Chronic Obstructive Pulmonary Disease COPD.

Wouldn’t it be nice to know how you would respond to altitude prior to reaching your destination, so you could be better prepared?   

There is such a test. It is called HAST: High Altitude Simulation Testing. This test can simulate 8000 feet in elevation, in the safety of a doctor’s office at lower elevations.  HAST is a diagnostic test that can effectively calculate an individual’s supplemental oxygen needs prior to traveling to high altitude. The California Thoracic Society recommends that individuals diagnosed with severe airway disease, cystic fibrosis, neuromuscular disease, kyphoscoliosis, individuals who have been hospitalized for acute respiratory illness within the last 6 weeks, individuals with previous air travel intolerance, COPD, or cerebral vascular disease would benefit from a HAST prior to traveling to altitude (Corby-DeMaagd, 2020).

This test is performed by obtaining a patient’s blood pressure, heart rate/rhythm, and oxygen saturation at baseline. Once baseline vitals are complete the patient is monitored while breathing in a mixture of gases containing approximately 15.1% oxygen, simulating the FiO2 at an elevation of 8,000 feet. A patient;s oxygen saturation levels can be recorded by an arterial line (large IV in the wrist) monitoring the patient’s arterial blood gasses, or by an oxygen monitor attached to the patient’s finger or on a nasal cannula. This allows the physician to screen for hypoxia, arrhythmias, or other significant symptoms. If the patient becomes symptomatic, the oxygen levels are reassessed while providing the patient with supplemental oxygen to identify exactly how much oxygen would be needed to keep the patient comfortable at a higher altitude.  This test on average takes 2 hours to complete (Corby-DeMaagd, 2020).  

According to Mark Fleming, the supervisor of the Pulmonary Physiology Services at National Jewish Health in Denver, Colorado, for an individual to receive a HAST they would need a referral from a provider.  National Jewish Health is one of the few facilities in the nation that provides this service. Most patients that request this test in the state of Colorado are pilots that have had a recent ailment and need a work clearance prior to being exposed to the airplane cabin pressure, those that are interested in relocating to the mountains, planning on a high-altitude vacation and currently on supplemental oxygen, or those with a history of pulmonary embolism or lung resections.  Fleming states that they are anticipating an increase in High Altitude Simulation Testing being needed for patients that have recovered from COVID-19.  

However, there may be a vulnerable population that is not receiving the benefit of this test. Newborn babies that are delivered at 5000 feet but must return home to 8500 feet. Those that have experienced a chest trauma and must return home to altitude. Or maybe even those that have experienced an invasive surgery that involved the lungs, chest, spine, or abdomen.  These are all individuals that would benefit from knowing if they would need oxygen once they return back to elevation. Hopefully as people continue to heal from COVID the word will spread that this test is available to the public for those that are concerned about journeying to altitude.

Amanda Bergin is currently in her second year of her Family Nurse Practitioner Program for the Rural and Underserved at Regis University. She is a member of the class of 2021 and will be graduating in August. She started her medical career as a corpsman in the United States Navy and after the completion of her service, she returned to school to complete her bachelor’s degree of Science in Nursing at the Denver School of Nursing.  Amanda currently lives in a rural mountain community with very limited healthcare, and dreams to help her community start a family practice clinic. In her free time, she loves spending time with her family, fishing, camping and raising dairy goats.

Effects and management of altitude on pre-existing cardiac conditions

As someone with family history of cardiac illness and a personal history of both supraventricular tachycardia (SVT) and high blood pressure, I have always tried to manage my modifiable risk factors through a healthy diet and exercise. Over the past year or two, most of my exercise has been in the form of running, since it is more conducive to the schedule of a physician assistant student during COVID restrictions. However, in the past I have been a regular rock climber and soccer player. Through my own personal experience I have noticed that when I stick to a healthy diet, not giving in to my sweet tooth, and keeping up with regular exercise that my episodes of SVT are less frequent. However, recently I traveled up from Denver, Colorado for a rotation at the Ebert Family Clinic in the mountain town of Frisco, and in the first two days at high elevation experienced an episode of SVT for the first time in nearly 6 months.

In my first day at over 9000 feet, I experienced a slight headache after a full day seeing patients, but did not think much of it or even consider it to be a side effect of the altitude. I spent my first day at altitude without exercising but I decided that on day two I had acclimated enough to go for a short run. Midway into my run, and shorter of breath than I expected, I experienced an episode of SVT that lasted for about 2-3 minutes and forced me to sit for several more minutes to catch my breath. Catching my breath afterward took slightly longer compared to my normal episodes, which made sense to me given the reduced availability of oxygen, but it did lead me to wonder if the altitude was a contributing factor to precipitating an episode of SVT after several months without one.

About one year ago, High Altitude Health interviewed Dr. Peter Lemis, a cardiologist in Summit County, Colorado about his thoughts and findings practicing cardiology at elevation. The discussion included questions about arrhythmias at altitude and Dr. Lemis stated that “studies have shown that cardiac arrhythmias are increased initially, but people become acclimated after about 3-5 days and the risk returns to baseline”. However, Dr. Lemis also states that the studies may not have been conducted for a sufficient length of time due to his personal experience of seeing a great deal of both atrial fibrillation and atrial flutter in his own practice. He states that the hypoxia leads to an increase in arrhythmias, but that for atrial arrhythmias, patients may experience relief from them when placed on nocturnal oxygen. Dr. Lemis also notes that “many people have central apnea during sleep at altitude due to the brain’s blunted response to high CO2 and low O2”, which can be a risk factor for the development of heart problems. The use of Diamox can be helpful in acclimating to altitude due to making “your blood a little acidotic which increases your respiratory drive” and the use of nocturnal oxygen can also help with acclimatization to altitude.

In March of 2021, the journal of Frontiers in Medicine published an article titled Nocturnal Heart Rate and Cardiac Repolarization in Lowlanders with Chronic Obstructive Pulmonary Disease at High Altitude: Data from a Randomized, Placebo-Controlled Trial of Nocturnal Oxygen Therapy by Maya Bisang, Tsogyal Latshang, Sayaka Aeschbacher, et al. This study compared COPD patients at altitude with and without oxygen therapy at night and COPD patients not at altitude without oxygen looking at QT interval, heart rate, and SpO2. The results of the study found that without oxygen use at altitude patients experienced an increase in heart rate, a lengthened QT interval, and naturally, a lower SpO2 at night compared to those at altitude who utilized oxygen and those that were not at elevation. This study was observing patients that had COPD. The results could potentially be relevant to younger patients without COPD, like myself, but would need further research.

I also looked into information regarding high blood pressure at altitude and found some helpful information from the Institute for Altitude Medicine. They state that for patients visiting altitude with a history of hypertension (HTN), even if it is well controlled on pharmacotherapy, may still experience a temporary increase in blood pressure at altitude. “One explanation for this is due to the higher levels of adrenaline or stress hormones in your body due to lower oxygen levels,” as they describe. Their research has also found that increases in blood pressure at altitude generally return to base line after 1-2 weeks. In order to help manage HTN at altitude they recommend ensuring that blood pressure is well controlled at sea level, reducing salt from the diet, remaining on any medications for HTN, checking blood pressure at altitude, and observing for symptoms of HTN that would need medical care such as headache, dizziness, chest pain, or shortness of breath.

Through my research regarding effects of altitude and the possible role of them in my recent episode of SVT, I have found that altitude can have several different impacts on cardiac function that definitely could have played a role in triggering an episode. Coming to altitude, I likely had an increase in blood pressure to compensate for the reduced availability of oxygen that increased strain on my cardiac muscle. I may have had EKG changes overnight related to decreased responsiveness of my central nervous system to CO2 levels. I also had an increased risk of arrhythmia based on coming to elevation. It is possible that any or all of these effects could have contributed or triggered my episode of SVT. Thankfully, after almost a month of staying at altitude I have adjusted more and have not experienced another episode. I have continued to exercise after a short break to allow more time to acclimate, but I have not pushed myself as hard.

I have learned that no matter how healthy you are or what your risk factors are, there are important steps to stay healthy when coming to altitude. If possible, at least one day at an intermediate altitude can help your body begin to adjust to the change. Drinking plenty of water to stay hydrated and avoiding alcohol can lead to a more comfortable stay and more rapid acclimatization. Meeting with a healthcare provider could also allow you to start a prophylactic course of Diamox or supplemental oxygen use. Utilizing a personal pulse oximeter allows you to monitor your SpO2 level and determine if nocturnal supplemental oxygen could be useful as well. If you have risks for cardiac conditions or already have a diagnosis of heart disease, these recommendations are even more important to prevent poor outcomes including myocardial infarctions due to reduced oxygen availability. Finally, it is important to remember that traveling to altitude is not a benign choice and a discussion with your healthcare provider is important to be sure that your personal risks are appropriately managed so that you can enjoy your trip to high elevation.

Justin Frazier is currently in his second year of PA school at Red Rocks Community College in Arvada, CO, a member of the class of 2021 graduating in November. He attended Appalachian State University in Boone, NC for his undergraduate degree majoring in Cell and Molecular Biology with a double minor in Chemistry and Medical Humanities. During his undergraduate he worked for two and a half years as a CNA at a local nursing and rehabilitation facility. After completing his undergraduate degree he started working as an EMT for almost a year before transitioning to work in a family medicine office where he worked as a Medical Assistant until starting PA school. He enjoys working in a primary care setting where he can help to keep people healthy throughout their lives and wants to pursue a career in pediatrics after graduating this year. He enjoys hiking, camping, rock climbing, and spending time with his wife and young son.

A Summation of Wilderness Medical Society Clinical Practice Guidelines for Diabetes Management

According to recent research, nearly thirty million individuals in the United states have been diagnosed with diabetes. Due to this higher rate of prevalence, more people are aware of the basic information surrounding a diabetic diagnosis.  However, there are common misconceptions surrounding the average diabetic patient, with most information focused on the more common form of diabetes, type 2. Although the majority of diabetic patients in the United states do have type 2 diabetes, an estimated 5 to 10% of people with diabetes actually have type 1. Type 1 diabetes is an autoimmune disease in which the body’s own immune system destroys the cells in the pancreas that make insulin. Insulin is a very important hormone that enables sugar to enter the bloodstream in order for it to be used by the cells for energy, as well as stored for later use. Unlike type 2 diabetes, there is no cure for type 1 diabetes and the treatment options are limited; the only management for this form of diabetes is insulin therapy. The most common therapeutic regimens for type 1 diabetes includes constant monitoring of blood sugars using a glucometer or continuous glucose device. These devices combined with either syringes, preloaded insulin pens, and/or an insulin pump are the means to survival for type 1 diabetics. However, there have been many advancements in the ways physicians are able to help their type 1 diabetics control and manage their disease.  Because of this, type 1 diabetics are able to live their lives with far less complications.  When desired, type 1 diabetics are able to compete at high levels of activity and complete amazing feats, such as wilderness activities.

It is inspiring to know how type 1 diabetics are still able to perform in high intensity activities such as ultramarathons, ironmen/ironwomen, as well as professional sports, to name a few.  However, with such strenuous activity, it is important to note that diabetes control is more challenging.  Of note, it cannot be stressed enough, that baseline diabetic control is already challenging in itself.  By adding the addition of a strenuous environment and activity, diabetes control becomes more difficult as it is multifactorial.

To help address this issue, the Wilderness Medical Society (WMS) worked to form clinical practice guidelines for wilderness athletes with diabetes. The WMS gathered a group of experts in wilderness medicine endocrinology, primary care, and emergency medicine to compose these guidelines.  These guidelines are outlined for both type 1 and 2 diabetics who participate in mild-vigorous intensity events in wilderness environment with reduced medical access and altitudes greater than or equal to 8250ft; the objective to help individuals with diabetes better plan and execute their wilderness goals. The foundation summarizes their recommendations into pre-trip preparation, including a list of essential items to bring when on your wilderness trip, potential effects of high altitude on blood glucose control and diabetes management, and an organized algorithm to treat hyperglycemia and ketosis in the backcountry.

Effects of High Altitude on Diabetes Management:

At baseline, the various types of exercise activities are broken into aerobic, anaerobic, and high intensity exercise. Each type of exercise utilizes the energy stored in our bodies, in the form of sugar. In a healthy person without any comorbidities, during aerobic activities, glucose uptake into the large muscle groups is increased due to the increase in energy expenditure. To keep glucose higher during this form of exercise, insulin secretion is reduced. Simultaneously, other hormones such as adrenaline, cortisol, and glucagon are released into the system to promote further glucose release from processes such as gluconeogenesis and glycogenolysis.

Again, the body is utilizing its resource of glucose to move to the larger muscle groups to keep them moving and active. During anerobic and high intensity exercise, the same process occurs, but since these forms of exercise tend to be in short bursts, insulin levels tend to rise particularly in the post workout period.  This helps to diminish the effects of the counterregulatory hormones and keep blood sugar levels stable. If the athlete is unable to properly regulate insulin secretions during these various forms of exercise, then it is likely that he/she will experience frequent episodes of hyperglycemia. Also, due to the increase in insulin sensitivity in muscles post workouts lasting >60 min, hypoglycemia can also ensue.

In general, the WMS and other research demonstrates brief episodes of high intensity exercise are linked to hyperglycemia for diabetics. On the other hand, longer duration aerobic exercise will cause hypoglycemia. Unfortunately, due to the complex intricacies of glycemic control during exercise, in addition to the individuality of each patient and the multiple variables involved in each wilderness expedition (temperature, altitude, duration, etc.), the definitive guidance for adjustment of daily insulin continues to need refinement. This is why the WMS recommends extensive pre-trip planning with the various tools, research, and supplies that will be needed when planning any form of wilderness adventure.

Pre-trip Prep:

Like all endeavors, preparation is key in order to be better equipped to deal with the majority of future scenarios.  Planning is especially important when going on a wilderness expedition. Preparation becomes even more important with the diagnosis of diabetes. The WMS outlines the specific recommendations that should be included as a diabetic wilderness athlete. For example, pre-trip prep should generally include: (1) a medical screening, (2) research of the endeavor and how it may affect glucose management, and lastly (3) essential diabetes-specific medical supplies and backups.

Additionally, according to the American diabetes association, persons with diabetes should discuss with their primary care provider and or endocrinologist before a strenuous wilderness activity. This follow up ensures that athletes are up to date on their screenings, health maintenance labs, and prescriptions needed for therapy. Due to the various ways that diabetes can affect the body, the WMS also recommends that if a patient has cardiovascular involvement, retinopathy, neuropathy, or nephropathy, there should be a more extensive risk assessment by the provider. Although these complications are less commonly seen in high intensity wilderness athletes, adequate histories should be taken to avoid adverse circumstances.

As discussed earlier, altitude accompanied with increased strenuous exercise demands also has various effects on blood glucose management. As it pertains to altitude and blood sugar management in type 1 diabetes, multiple studies have shown an increase in insulin requirements at altitudes above 4000m (13,123′). At this time, researchers are unsure if this finding is due to the effects of acute mountain sickness or hypobaric hypoxia. Therefore, wilderness athletes with diabetes should be aware of the insulin resistance increase at these extreme altitudes.  In conjunction with altitude changes, as previously noted, the type of exercise will also play a role in insulin control.  Aerobic exercise for longer than 60 minutes can cause a hypoglycemic episode in type 1 diabetics due to the increased muscle sensitization to insulin. Therefore, at altitudes 4000m or above, wilderness athletes will be in a mixed long duration anaerobic/aerobic exercise. With the combination of these factors, there is a counter regulation effect, and the athlete becomes both more sensitive to insulin due to increase duration of exercise and less sensitive due to altitude demands. In order to better predict the effects of altitude combined with exercise, the WMS recommends close monitoring on shorter trips to recognize their specific glycemic trends prior to an extreme high-altitude expedition, as well as increased close monitoring of glucose management during their high-altitude endeavors.

Table 1: Environmental Effects on Diabetes, Imported from WMS

Lastly, in preparation of a high-altitude excursion, there are recommended items that should be packed for daily management of glucose, in addition to back up items to ensure athletes with diabetes aren’t left in a dangerous situation. Fortunately, the WMS was able to create a well-organized table on the recommended supplies.

Table 2: Medical Kit Preparation, Imported from WMS

Treatment of ketoacidosis or HHS:

To be properly prepared, an athlete should complete his/her own research on how changes of altitude and exercise can affect blood glucose management.  This includes complete pre-trip preparation and packing.  Once cleared, a diabetic athlete can finally head out on the high-altitude adventure. In case of emergency, a diabetic should be aware of the proper steps if he/she were to experience diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), or even acute mountain sickness (AMS). Hyperglycemia is described as a blood glucose greater than 250 mg/dL and without adequate treatment can lead to either DKA or HHS. Type 1 diabetics are more likely to go into DKA, while type 2 diabetics are more inclined to present in HHS. One of the most important indicators if a person were to be in DKA are ketones in blood or urine. This is why it is very important to make sure a wilderness athlete carries ketone strips in his/her emergency medical pack. Typically, if a patient finds ketones in their urine after using a ketone strip, then he/she is educated to seek emergent medical attention. When on a wilderness adventure, this can be a difficult task to accomplish. This is why the WMS also developed a flowchart in order to manage hyperglycemia and DKA without medical support. Refer to table 3 for their flowchart.

Table 3: Algorithm for management of hyperglycemia and ketosis in the backcountry. EDD, estimated daily dose, PO, oral intake, Imported from WMS

One issue that diabetics have when dealing with high-altitude is differentiating hypoglycemia and hyperglycemia side effects from AMS. The most reliable differentiating factor is increased blood sugar readings correlating with symptoms. WMS states that either a continuous glucose monitor or increased finger sticks for a higher frequency of blood sugar readings is important to determine if a person with diabetes is experiencing blood sugar complications of AMS. When discussing treatment of AMS in diabetics, the same methods are used as are recommended for a non-diabetic individual: Acetazolamide and dexamethasone in initial medical management. In regard to diabetes, it is important to discuss the potential additional side effects. Acetazolamide can worsen dehydration and acidosis if used at the wrong time. Dexamethasone is known to worsen blood glucose control. Both are still useful in acute mountain sickness but must be weighed against causing worsened complications.

Conclusion:

When participating in a wilderness adventure, individuals with diabetes will be prone to more medical side effects. Changes in altitude, along with the level of activity are known to affect diabetic control, so proper preparation prior to departure is required in order to ensure the health and safety of a diabetic wilderness athlete.  After being cleared by a medical professional and obtaining proper information, diabetics can plan to complete a wilderness adventure similar to that of a healthy individual with no comorbidities.  However, it is common for diabetics to experience hyperglycemia with high intensity activities and an increase in altitude. Therefore, diabetics (particularly type 1 diabetics), should be prepared with extra insulin to counteract elevated glucose levels. Alternatively, if a diabetic were to be at higher altitude with a longer duration of aerobic or anaerobic exercise, then he/she may be prone to hypoglycemia — lower blood sugar levels.  In either case, individuals with diabetes will need to monitor blood sugar levels more closely.  The WMS provides diabetics with an outline of recommended supplies that may be needed in the wilderness.  The outline also suggests for diabetics to bring ketone strips, as this is the most accurate measurement to determine if a diabetic is in DKA or HHS.  The ultimate goal of the WMS is to ensure the health and safety of diabetic athletes. Diabetes is a difficult disease to manage but becomes even more challenging when partaking in a wilderness adventure.

(All tables and figures imported from WMS)

References:

de Mol P, de Vries ST, de Koning EJ, Gans RO, Tack CJ, Bilo HJ. Increased insulin requirements during exercise at very high altitude in type 1 diabetes. Diabetes Care. 2011;34(3):591-595. doi:10.2337/dc10-2015

VanBaak KD, Nally LM, Finigan RT, et al. Wilderness Medical Society Clinical Practice Guidelines for Diabetes Management. Wilderness Environ Med. 2019;30(4S):S121-S140. doi:10.1016/j.wem.2019.10.003

Jonathan Edmunds is a second-year physician assistant student at RRCC PA Program in Arvada Colorado. Jonathan is a Colorado native, born and raised in Littleton, CO. He attended Colorado State University in Fort Collins, CO where he competed in Track and Field as a long jump/triple jumper, as well as earned his bachelor’s Biological Sciences. During his junior year in college, he was diagnosed with Type 1 diabetes and quickly became an advocate the support of diabetes education. After graduating in 2015, he focused his medical career aspirations on becoming a PA. He volunteered at Banner Fort Collins Medical Center and work at Bonfils Blood Center as a phlebotomist for 2 years before applying to PA school. In his free time, he enjoys coaching track and field at Littleton high school his alma mater, doing all things outdoors, and cozying up to his three “Irish” chihuahuas at home. 

Doc Talk: a Californian Interviews South America’s Altitude Experts Dr. Gustavo Zubieta-Calleja & Dr. Natalia Zubieta-Urioste

As a California native, I was unfamiliar with the impact high altitude had on the human body. I had only briefly learned about it in my exercise physiology course during my undergraduate studies. At best, I understood the difference between acclimation and acclimatization, and the advantages of living at high altitude for exercise performance. What I never really understood was how much all that information would mean to me when the next chapter in my life took me to Colorado.

In hindsight, I did everything against the book after moving to Colorado because I wanted to stay active and enjoy as much as I could before school started. I continued my daily workout routines, went whitewater rafting, and had a few drinks. More importantly, I was not hydrating adequately because I didn’t know you could drink straight from the tap. So… what happened? The end of my workout routines was met with dizziness and lightheadedness. On some occasions, I would notice my fingertips turn purple. My sleep would be interrupted by episodes of apnea. Though these symptoms did resolve eventually, they could have been prevented if I had followed a few simple rules.

As a student at Ebert Family Clinic in Frisco, CO at 9000′ alongside high altitude expert Dr. Christine Ebert-Santos, I had the opportunity to learn more about high altitude illness, interviewing Dr. Gustavo Zubieta-Calleja and his daughter Dr. Natalia Zubieta-Urioste from the High Altitude Pulmonary and Pathology Institute (IPPA) in La Paz, Bolivia. Dr. Zubieta has been practicing internal medicine and pulmonology at his father’s high altitude clinic since 1981. During our interview, we discussed their most recent publication Acute Mountain Sickness, High Altitude Pulmonary Edema, and High-Altitude Cerebral Edema: A view from the High Andes. When asked about what inspired him to follow his father’s footsteps, he replied, “My father created the first high altitude clinic in the world and that was a great inspiration to me. He did it with a visionary idea because at the time in 1970, nobody thought about putting a clinic like that out. I was born at home because my father was a physician and he preferred to deliver us. We [me and my siblings] were all delivered at home and then that home became the clinic in 1970. The clinic turned 50 this past year and our father also became our mentor at this clinic.”

The article addresses the two types of adaptation: genetic and physiologic. In his publication, he primarily addresses the physiologic mechanisms that must occur for one to adapt to the hypobaric environment that is high altitude. During my research, however, I found that Tibetans experienced the fastest phenotypically observable evolution in human history partially because their community has spent centuries living at that altitude. When I discussed my findings with Dr. Zubieta, he stated that much still needs to be done to determine if the Andean population has made similar genetic adaptations. He was optimistic about the studies to come as he strongly believes that all organisms must adapt if they want to survive and reproduce at high altitude. According to Dr. Zubieta, change is inevitable. He believes that the energy expenditure from the body’s initial response to the hypobaric environment is too costly forcing  the human body to adapt in a manner that will render it more effective in managing this energy expenditure via metabolism at the mitochondrial level.

We also discussed the different attitudes towards the use of acetazolamide, or Diamox. In the United States, acetazolamide is a diuretic commonly used to prevent the onset of acute mountain sickness. Dr. Ebert Santos highly recommends the use of acetazolamide to prevent acute mountain sickness while Dr. Zubieta and other providers reluctantly use it due to the risk of dehydration. A 125-milligram dose is adequate and unlikely to cause side effects, which Dr. Zubieta said can include fatigue, nausea, vomiting, abdominal pain, and diarrhea. (Most visitors to Colorado taking acetazolamide only experience tingling of the hands and feet and a flat taste to carbonated beverages.) Dr. Zubieta justifies his avoidance of acetazolamide as an “opportunity” to treat the patient’s underlying issues, stating that ascension to high altitude is a testament of one’s cardiovascular fitness and the use of acetazolamide compromises adaptation to high altitude. At the IPPA they have uncovered underlying conditions that explain their patients’ symptoms at altitude and resulted in better health upon returning to sea level.

 The Wilderness Medical Society has established a risk stratification for acute mountain sickness which further supports Dr. Zubieta’s infrequent use of acetazolamide. The society’s 2019 guidelines suggest that individuals with no history of altitude illness and ascending to an elevation no greater than 2,800 meters, and individuals who take more than two days to arrive at an altitude between 2,500 and 3,000 meters are considered low risk and the use of acetazolamide is not recommended. Instead, Dr. Zubieta recommends Ibuprofen and Acetaminophen for headache relief and oxygen in those with persistent symptoms of acute mountain sickness. He also emphasizes that oral hydration can be important in preventing high altitude illnesses.

Overall, Dr. Zubieta’s perspective on high altitude is fascinating. During my master’s program, I learned a systematic way to treat patients using guidelines or criteria backed by years of evidence that helps you, the provider, make an informed decision on a patient’s particular case. Dr. Zubieta reinforced the importance of treating each patient’s case individually to determine the underlying cause, rather than suggesting acetazolamide to everyone who doesn’t want to deal with acute mountain sickness. As for myself, seeing how physicians in other countries approach certain illnesses has definitely made me think twice about how to approach high altitude illness.

To learn more about Dr. Gustavo Zubieta and his clinic, you can visit his website at: https://altitudeclinic.com/

Born and raised in Northern Orange County of California, Michael Le is a second-year physician assistant student at the Red Rocks Community College Physician Assistant Program in Arvada, CO. Michael attended California State Polytechnic University Pomona otherwise known locally as Cal Poly Pomona where he earned his bachelor’s degree in Kinesiology. Shortly after, he worked as an EMT for Lifeline Ambulance, and physical therapy aide and post-anesthesia care unit technician at Fountain Valley Regional Hospital in Fountain Valley, CA. In his free time, Michael likes to cook and breed show rabbits.

Doc Talk: ALTITUDE AND THE EYES, AN INTERVIEW WITH DR. PAUL COOK, OD

Have you ever wondered why a bag of chips will swell almost to the point of bursting when you travel from a lower elevation?  As the altitude increases  the barometric pressure decreases. The difference between the high pressure inside the bag and the low pressure outside causes the bag to swell (and sometimes burst) to reach equilibrium with the surrounding environment.

The same concept applies to our biological tissue, including our eyes. Luckily there is not normally gas in our eyes, but there are procedures where air bubbles are injected into the eye, such as a vitrectomy: part of the vitreous humor of the eye is replaced with air so that a nearby site has the chance to heal. Common indications include a retinal detachment, macular hole or removal of scar tissue. It’s important to remain at the elevation your ophthalmologist or optometrist indicates because you don’t want your eye to suffer the same fate as a bag of chips!

This was one of many interesting things I learned while speaking with D. Paul Cook, OD and his wife and practice manager Karen Cook at Summit Eye Center on Main Street in beautiful Frisco, CO. The following is my interview with Dr. Cook, Karen Cook, and my preceptor Christine Ebert-Santos, MD, MPS.

How many years have you been practicing optometry in Frisco, CO?

I don’t recall the exact year, but I remember it was the year the Broncos lost the Superbowl.

Dr. Paul Cook at the entrance of Summit Eye Center.

I did a little research and this must have been either the 1986 or 1987 season, as the Broncos lost both of those Superbowls. Fortunately, those Superbowl losses were not a bad omen as Dr. Cook has successfully served the Frisco area every year since.

What conditions do you see commonly here at altitude?

One thing I see commonly here is recurrent corneal abrasions. The classic patient lives at a lower altitude and previously had a corneal abrasion. They received treatment but the abrasion site never completely heals. After arrival in the high country where it’s extremely dry that abrasion site dries up and becomes inflamed.

Usually what I do is give a bandage contact lens to cover up that recurrent corneal abrasion, which usually works, but if it’s extremely painful, we can use amniotic membrane, which is expensive. But it is effective.

The cornea is the outermost layer of the eye (if you don’t count the tear film). A corneal abrasion occurs when any foreign object scrapes the corneal surface. Symptoms include a foreign body sensation, pain, clear discharge, blurry vision and sensitivity to light. A corneal abrasion needs a healthy, moist environment in order to heal. You can see how the dryness that comes along with altitude could lead to a recurrent corneal abrasion.

I also see a fair amount of snow blindness, usually in the spring though.

I suppose it has to do with the sun being higher in the sky and people being out and about hiking. When people are out skiing in the cold winter they wear their goggles, but if it’s spring time and somebody’s hiking they might forget their glasses.

Snow blindness is only one potential cause of a disease called photokeratitis. Other causes are staring at the sun, looking at an arc welder, or catching too many refracted UV rays from surfaces such as sun, water, ice and snow. The pathophysiology for each disease is the same: too many UV rays are focused onto the cornea at one time which causes damage. Symptoms include pain, redness, blurriness, sensitivity to bright light, headache, and occasionally temporary vision loss. Treatment for photokeratitis caused by snow blindness is supportive, but the most important thing is resting your eyes. Try to get into a dark room and avoid anything that makes your eyes uncomfortable. In a few days your cornea should heal.

Prevention  is straightforward: wear sunglasses or ski goggles with adequate sun protection.

Are cataracts a more common condition at altitude?

Oh yes, because of sun exposure and our aging population here. The people of Summit County are so active, which increases their exposure to the damaging rays of the sun. We’re also treating cataracts so much sooner than we used to, so that’s part of what makes it more common.

Do you have any recommendations for healthy aging at altitude as it relates to the eyes?

Karen: Getting your annual eye exam. We always tell patients there are a lot of things we can do to preserve your vision, there’s almost nothing we can do to give it back to you.

So if you live in Frisco, CO and don’t have an optometrist, make sure to see Dr. Paul Cook!

Is blurry vision a common malady in patients that have recently received a LASIK procedure and then ascended to higher elevations?

I have not seen that with LASIK. About 30 years ago though there was a procedure called Radial Keratotomy (RK) that involved a surgeon making radial cuts on the cornea in order to correct nearsightedness. Those patients used to require one pair of glasses for where they lived at lower elevation and one pair of glasses at higher elevation. It’s not a procedure commonly done nowadays but patients that had RK roughly 30 years ago may have that problem.

LASIK stands for Laser Assisted In Situ Keratomileusis. It essentially means that the surgeon will use a laser to reshape the cornea so that the light refracting through it will be appropriately concentrated on the retina. LASIK is faster, cheaper, safer and more effective than RK. It has largely usurped RK for surgical treatment of nearsightedness or farsightedness.

What are some interesting cases you have seen over your years of practice?

I treated a patient that traveled from the Midwest and had a genetic condition called retinitis pigmentosa. Clinically that means the patient had limited peripheral vision at baseline.  He and his wife decided to hike the Colorado Trail. Unfortunately during the hike he developed blurred vision and ended up coming into my office. Turns out he had macular edema and I referred him to an ophthalmologist down in Denver because the altitude was probably the cause of his macular swelling. I called him a few weeks later and his vision had returned to normal.

Another  patient came into the office because his wife had noticed growths on his iris that turned out to be nevi (colloquially known as moles when they’re on the skin). So I dilated his eyes and noticed growths on his retina. I referred him down to oncology in Denver for a biopsy and it turned out to be melanoma. I think they’re closely monitoring that melanoma at this point. It’s uncommon to see cancers of the eye but I see them once every few years.

Dr. Cook performing an eye exam on me.

For my last question, do you have any general recommendations for residents or visitors?

Wear sunglasses, eat your vegetables, eat your fish at least two times per week, keep your cholesterol in check, keep your sugars in check, take breaks from looking at the computer, don’t sleep in your contacts, and see your optometrist once per year.

Seth Selby is a second-year physician assistant student at Des Moines University. He was raised in Eaton, CO and attended Colorado State University with a bachelor’s degree in Health and Exercise Science. Prior to PA school, Seth worked for 3 years as a Cardiovascular Technician at Boulder Community Hospital. In his spare time Seth loves backpacking, hunting, fishing, skiing and astronomy.

Doc Talk: an Interview with Emergency Medicine Physician Dr. Jack Gervais

While doing a clinical rotation with Dr. Chris at the Ebert Family Clinic in Frisco, CO I had the pleasure of interviewing local emergency medicine physician, Dr. Jack Gervais.

To start off, if you don’t mind just telling us about yourself, where you work, and how you got into the ED

Dr. Jack Gervais: I grew up in Summit County and then did my undergrad at the University of Denver, and then medical school at University of Colorado in Denver as well, and then did a three-year residency for emergency medicine in Portland, Maine. Then I came back to Frisco in 2011, so this was my first job out of residency, and I’ve been here ever since. As far as what got me into emergency medicine, it just kind of seemed like a good mix of everything, really, and I like doing procedures but didn’t necessarily want to be a surgeon, and so I kind of gravitated towards that.

What percent of your practice involves tourists?

Dr. Jack Gervais: It depends on the season. Obviously during the higher tourist seasons it goes up, but I would say probably on average maybe 50-60% and then during the heavy winter tourism times it’s probably more like 80%, and fall and spring much less.

Let’s say that there is a visitor in Frisco who brought a pulse oximeter with them. At what point, with either their O2 saturation or their symptoms, would you recommend that they go to the ER or seek oxygen administration?

Dr. Jack Gervais: It really depends primarily on the symptoms. People can be symptomatic with a fairly typical kind of mountain sickness symptoms and have a normal oxygenation. We consider anything above 88-90% acceptable.  We get a lot of patients that come in with an ankle injury and their O2 saturation is 85% and they’re really asymptomatic. 

Certainly, anybody who’s symptomatic we will offer O2 to them even if they have a normal saturation. Anybody around 85-86% if they’re not having symptoms and they’re going home in a day or two, I offer oxygen to them, but I don’t necessarily say “oh you have to be on oxygen ’cause you’re 85%”. Anybody who’s under 80%, I would say absolutely should be on O2 regardless ’cause they’re going to end up getting worse.

Let’s say they’re skiing, they check their oxygen saturation, and it’s 85% but they feel fine. Would you say “keep going and be aware if you develop symptoms”? 

Dr. Jack Gervais: Yeah, I think that’s reasonable. People tend to do worse at night, so someone is 85% when they’re standing in the day, they’re probably in the 80s at night. So, what I’ll often do with people with those kind of borderline sats is offer them oxygen. It’s really easy to get the delivery from the various companies so it’s pretty straightforward, more of a cost issue for some people, but I tell them “use it when you sleep the whole time you’re here”. Probably most tourists would benefit from sleeping on oxygen regardless because you don’t know how low they’re getting at night. I would guess most people are sleeping in the mid 80s and don’t realize it. That leads to the headaches and waking up at night and those sorts of things that we see a lot.

What conditions do you see here at altitude and how commonly, i.e. cases of Acute Mountain Sickness (AMS), HAPE (High Altitude Pulmonary Edema), HACE (High Altitude Cerebral Edema), sleep problems, blood pressure issues, etc.?

Dr. Jack Gervais: Typical AMS would be shortness of breath, headache, and nausea being the most common. Any combination of those in people who recently traveled from lower elevation or when locals come back from as few as 4 days of vacation can be AMS. People reset really quickly after they descend, we see a lot of people who get reentry HAPE. Kids will go down for spring break in Florida and come back and get HAPE.

It’s tough to say exactly what incidences, I would estimate probably 20-25% at least people visiting from lower elevation — and that’s when it’s just semantics, but it’s elevation, not altitude, and everybody says “altitude sickness”. Altitude is your height above the ground used by pilots. Elevation is how high you are above sea level, but anyway we see that all the time. That’s pretty simple, you know, basically treat the symptoms: something for nausea and actually ibuprofen has been studied in comparison to acetazolamide and is essentially as effective at preventing acute mountain sickness. I tell everyone just put yourself on an NSAID as long as there’s no clear contraindications to it.

I see at least 12 patients a month with HAPE, so it’s something we see really commonly.  This year is kind of weird though ’cause we’re not having as much tourism. We see a lot more when a storm comes in ’cause the pressure drops-so that 10% drop in barometric pressure is like going up another 500 feet, and so that will often kind of push people over the edge. Again, we tend to see a lot of people who get worse at night because they sleep with low O2 saturation or they struggle through the night and come in first thing in the morning saying “I didn’t sleep at all last night, I’ve got this terrible headache, I’ve got this cough”.

HACE is fairly rare here, but not impossible at this elevation. It’s certainly seen more in high trekkers on Everest and in South America. I would say at the hospital we probably have maybe 3-4 cases a year.

Sleep problems are super common, a lot of people wake up feeling short of breath, they’re dehydrated, they get headaches and of course everything else people are doing on vacation exacerbates all that. We actually have this joke of the Summit County Syncope Syndrome: visiting from low elevation, hot tub, alcohol, overexertion, and cannabis. If you have 3/5, there is no way that your syncope is a dangerous cause!

I don’t know why people bring their blood pressure monitors on vacation, but we definitely see a rise in baseline blood pressure at higher elevation. They say, “I have a little headache” (it’s probably from their acute mountain sickness), they check their blood pressure and its 160 and they end up in the ER, which they don’t need to be.

There are actually some folks at the altitude research center in Denver [who] have a little publication about it, but I certainly see a lot of first-time seizures or breakthrough seizures in people who have never had a seizure before. I think it’s just that little bit of change in oxygenation to the brain if you have a seizure predisposition. We see a lot of people that either have their first-time seizure, and there’s nothing else going on, or they’re really well controlled at home, come up and have a breakthrough seizure a couple of days in.

 One other thing about HAPE that’s interesting is people will come in and they’re like, “oh I haven’t slept for the last two nights, I feel terrible, I’ve had a splitting headache,” and I assume they’ve had that for 24-72 hours before they actually come in. Which means they’ve been sitting around with [low oxygen] — most of the HAPE we see is certainly below 80%. I presume these people have been walking around with sats in the 70s for 24-48 hours and it’s amazing that they’re fine. If you were walking around with your O2 saturation in the 70s at sea level, you’d be dead! So, it’s not just a hypoxia that kills people when they have respiratory illness, it’s got to be the hypercarbia and acidosis and all the other stuff that goes along with it.

HAPE tends to also settle in around day 2-3, some people get it quickly but most of the people say I felt fine on day one, I skied yesterday, felt a little crummy night 2, and then day 3 they feel terrible, night 3 can’t sleep and they’ve got HAPE.

 It’s interesting to see the nurses check in a patient with an O2 sat of 50% and it is really no big deal, just put him in any room — it’s not like a big STEMI activation or something. We stick them on oxygen and no one freaks out. People freak out on their first shift if they’re new and it took me a good year to kind of get used to that.  

 Often, we don’t really need to do anything if we can fix them with oxygen and determine from history and physical that there’s nothing else going on. But that gets tricky ’cause you always worry all these people traveling and they’ve got a little bloody cough, they’re tachycardic and hypoxic, so trying to figure out who we want to work up for a PE (pulmonary embolism) is probably our biggest conundrum. A lot of people will get a little bit of a troponin bump just from probably that hypoxic constraint on the heart so that can be a little tricky to figure out who needs to go get a cardiac work up.  

What does a classic HAPE patient look like?

Dr. Jack Gervais: A healthy 26-year-old male who’s got the classic story of progressive increase in shortness of breath, feel like there’s fluid in their lungs, a raspy cough, a little pink sputum, and their sat’s 65% and they get better pretty quickly on oxygen.

What is the typical treatment for HAPE?

Dr. Jack Gervais: The treatment for HAPE patients is to put them on high flow oxygen, around 15 liters.  So, with HAPE, patients get inflammation and acute pulmonary hypertension which causes fluid buildup in the lungs. So, oxygen is really good at reversing that. We oxygenate the lungs which opens up those blood vessels, reduces the pulmonary hypertension, and that fluid can start to resorb in the lungs.

The typical HAPE patient is in the emergency department for 1-3 hours depending on how bad they were and how they’re doing on the high flow oxygen. We wean them down, with a goal of getting them on a nasal cannula with 3-4 liters of O2, which is what the O2 concentrators and portable O2 tanks can manage. And if we can keep someone above 90% on 3-4L they go home with an oxygen prescription. I tell those people to be on oxygen for 24 hours and to just rest and see how it goes, see how you feel. If you start feeling bad again you should be on oxygen. Rarely we see patients come back in because they aren’t doing well, and those people who do, we tell them, “OK you’re out, time to go down to Denver until your plane leaves”.

Are there any medications you use to treat high altitude illnesses?

Dr. Jack Gervais: I don’t tend to use a lot of other medicines. If the oxygen works, why bother adding a bunch of side effects from medications. Some providers tend to be a lot more into giving nifedipine, a calcium channel blocker, which does reduce pulmonary hypertension. A lot of them will use dexamethasone, but it doesn’t so much help with the respiratory component it tends to help more with the headache aspect, but the oxygen will often fix that too. Dexamethasone is also the temporizing treatment for HACE, but they need to descend immediately. People will use Acetazolamide (Diamox), but it’s really only effective if you start it 2-3 days before you come up to the higher elevation. Starting it after you’ve already got acute mountain sickness is probably worthless and it’s got some funky side effects that makes anything carbonated taste weird and it’s a diuretic so you’re adding dehydration to someone who’s already a little dehydrated.

I tend to be more of a minimalist, so I treat the symptoms and give oxygen if they need it and pretty much leave it at that. I was just listening to a podcast talking about inhaled vasodilators. Inhaled/nebulized nitroglycerin — it goes directly to the pulmonary vessels as a vasodilator, but you don’t get the systemic vasodilation that you would with nifedipine or oral nitroglycerin. This was talking more for acute exacerbations of chronic pulmonary hypertension among other things, but I have to wonder if that would work for our patients.

I know you mentioned ibuprofen, but are there any other over-the-counter options you might suggest someone try for AMS?

Dr. Jack Gervais: There are a whole bunch of supplements and stuff that claim to help with altitude sickness, they’re just not studied in any real scientific way to know for sure. For me it’s really just treating the symptoms, so I usually use Zofran for the nausea or Phenergan if there’s a contraindication, and then alternating Tylenol and ibuprofen and oxygen if needed. So, nothing else as far as a preventative that I’m aware of. If you kind of get into the naturopathic realm there’s probably a whole bunch of suggestions out there.

Everyone fixates on staying hydrated which is important. You’re losing extra fluid and if you’re used to living in Florida, you’re going to lose A LOT of fluid when you come up to higher elevation because of the dry air. I tell most people to try and double what you would drink at home. Hydration is really most effective with the headache part of it. It doesn’t change whether you’re going to get HAPE or not. 

Oh, and the little oxygen cans you see in the convenience stores … those are garbage! For oxygen to be effective it needs to be on continuously. Even if you puffed on that thing for a minute and could get your O2 saturation up from 85% to 90% it’s going to drop right back down. In the hospital, if you turn the oxygen off, their saturation will be back where it was within minutes, so yeah, those things are just a total waste of money.

What has been your experience with COVID-19? 

Dr. Jack Gervais: Luckily, we have had it much better off than places like New York, LA, and even down in Denver. I think that part of it is that overall, we have a pretty healthy population compared to a lot of the bigger city areas and suburbs. There have been some studies out there suggesting that people living in higher elevations do better with COVID than lower elevations and I don’t know if it’s just ’cause your body and your pulmonary system has adapted in some way that helps you deal with COVID, but we’ve certainly had some perfectly healthy local folks get pretty sick from it. 

When the tourists were gone back in March/April/May it was great because everyone is local and if you had respiratory symptoms it was probably COVID. Now that the tourists are coming back, it’s a lot harder to tell clinically, and the other thing is the x-ray in HAPE and the x-ray in COVID look very much the same.

We had one patient in particular who came in and said, “I got here yesterday, had a positive COVID test 14 days ago,” and of course they thought they were fine to come up to the mountains, and sure enough they were short of breath. The people who are foolishly traveling either with active COVID or on the tail end of it do not adapt very well when they get up to this elevation, but most of them just need some oxygen.

We finally have rapid tests at the hospital, so it makes it much easier to kind of tell people “this is just altitude” or “this is altitude plus COVID” or “this is straight-up COVID”. In the summer when we didn’t have a rapid test, we’d get these people who have the overlapping symptoms that could be either. It’s tough to tell them what they should do as far as self-quarantine and isolation.  Can you travel? Can you go try to ski tomorrow because it was just altitude sickness?  

The treatment for COVID ends up being the same: oxygen if you need it and then actually dexamethasone has shown to be effective for patients with COVID who are requiring oxygen.

Even before COVID we would send patients home on oxygen with pneumonia or URI symptoms fairly routinely, which is really not a thing in other places. If you need oxygen with pneumonia in Portland, ME you’re getting admitted. If I called Dr. Chris and said I’ve got a kid of yours who looks like they’ve got bronchiolitis or a URI or even COVID, their sat’s 85% — the answer is almost always going to be “oh, put them on oxygen and if they are OK on a reasonable amount of oxygen they’re probably OK to go home”.

Do you admit COVID patients to the hospital up here if needed?

Dr. Jack Gervais: It’s been really tricky for us to figure out who we can reasonably admit here versus transfer to Denver. Both need to have a higher level of care and be at lower elevation. We have kept COIVID patients here successfully. The thing is, even if you live up here and are used to the altitude you’ve got a respiratory process and you’re hypoxic as a result, it makes sense that you would probably do better down in Denver and probably have less of an oxygen requirement and hopefully not progress to high flow oxygen. You can get someone on high flow here but then they’re stuck here until they get better or they get intubated to be transferred.

What is the most memorable case that you have seen in the ER related to high altitude?

Dr. Jack Gervais: So, I had a professional snowboarder who had gone back to sea level for the summer and then flew back out here and had a shoulder surgery in Vail and was staying in Summit County. He was a day or two post-op and had probably been back in the mountains for three or four days so kind of fit the time frame to develop altitude sickness, and he’s probably on a muscle relaxant, some opiates, some respiratory depressants. So, this is the very end of the night shift, I had a STEMI going on in the other room and this guy comes in at 84-85%. He didn’t look super sick but needed some oxygen. I’m like, “oh, he probably took too much oxycodone,” and so I throw him on some oxygen while I go back and deal with this STEMI.

 I go back, and he wasn’t any better! He was still at like 86% on high flow oxygen. So, we got a chest x-ray and he had a little bit of fluid here and there, so it looks like probably early HAPE, or potentially pneumonia, but fit with more of an altitude issue exacerbated by his post-op care.  So, we put him on Bipap and he’s not getting any better and now he’s low 80s on Bipap, so we intubate him.

Now he’s getting worse and now he’s dropping his blood pressure. This is over probably an hour, so this guy is sick, and we could not get him oxygenated even on max vent support. We were begging him, and I thought he was going to just die right in front of me. Finally, he dropped his blood pressure more and we’re like “well, maybe he’s septic, maybe he aspirated, and this is pneumonia.” So, we give him norepinephrine, which is a vasopressor, it constricts all the blood vessels to help increase the blood pressure and adds ionotropic support to make the heartbeat stronger. Then his blood pressure finally got better, and his oxygen got better, and he went down to the ICU in Denver and I’m like, “thank God I didn’t kill this guy at the end of a 13 hour night shift”.

So, it turns out — and this is what makes it the most interesting — he had a PFO, patent foramen ovale — so, a hole in his heart. It’s very common, but people tend to not notice because in general, the pressure in the left side of your heart outweighs the pressure in your right significantly so that patent foramen ovale stays closed against the septum.

Like I was saying earlier, HAPE is caused by acute pulmonary hypertension which then raises the pressures on the right side of your heart. So, he blew open his PFO and now had a right to left shunt — so blood from the right side of the heart doesn’t go up through the lungs and oxygenate, it goes straight to the left and goes back out into the body unoxygenated. That’s why everything we did made him worse. When you put someone on Bipap, and especially when you intubate them, you’ve got that positive pressure that increases the intrathoracic pressure, which increases the preload on the heart.

Dr. Chris Ebert-Santos: 30% of the population may have PFO!

Dr. Jack Gervais: Coincidentally, the norepinephrine that I put him on trying to treat as sepsis increased the after load — the arterial resistance, which then increased the pressure on the left side of the heart enough that it was able to squeeze his PFO back down.

Dr. Chris Ebert-Santos: The ironic thing is that it’s so random! All of this altitude stuff is SO random, even people who have had AMS or HAPE or whatever they may never get again. I mean 90% probably never have a recurrence.

Dr. Jack Gervais: Yeah people get really frustrated and say “I’ve been here 10 times before, it can’t be altitude sickness” — that can happen, and it does. People have this myth of like, “I used to live here, I’m fine,” and it’s absolutely false.

Another interesting thing you see at altitude is people with sickle cell trait (so not full-blown sickle cell disease, generally thought to be a harmless and completely asymptomatic condition) will get splenic infarcts when they come up. You almost can’t even find reports of it in the literature, but I probably see 8 or 10 a year. It’s kind of easy to pin down, the person is like, “I just got here, I’ve got this left upper quadrant pain, no trauma” — not much in your left upper quadrant, so most of the time the minute they hit triage you know what’s going on. We treat just like you would any sickle cell crisis: fluids, pain medicine, oxygen.

I know you mentioned the myth about people who have lived here before believing they aren’t able to get mountain sickness, but do you have any other myths that you frequently have to clarify?

Dr. Jack Gervais: The big one we run into is people who are taking acetazolamide wrong and are surprised that they’re having altitude sickness. People start getting symptoms and they call their doctor and they may prescribe it too late and I just tell them, “don’t bother”. 

People who think they’ve got an infection or bronchitis so their doctor back home calls in antibiotics, which they don’t need even if it is bronchitis. Or the people who ignore it for 2-4 days to assume it’s the bronchitis and say “the antibiotics aren’t working, doctor what’s wrong?” Well, your lungs are filling up with fluid! The good news is HAPE tends to be gradually progressive over hours to days, not minutes. Very rarely we see patients who are really actively dying from HAPE. In 10 years I have probably seen hundreds if not 1,000 HAPE patients and I’ve only probably had 2-3 who were really, really hard to fix. Probably 10-20 that I’ve had to put on Bipap and transfer down. I think I’ve maybe only intubated 1-2. People get in trouble if they’re up high — 20,000 feet on Mount Everest, don’t have oxygen, that’s where you’d end up dying with HAPE. 

Dr. Chris Ebert-Santos: And how many die at home?

Dr. Jack Gervais: I would say a handful. I’ve had at least one lady who was camping. Had HAPE-like symptoms and came in dying, she was the one I intubated, and she actually lived. I had a guy camping last summer who sounded like (from what his mom described) altitude-related symptoms, although he was just up from the Front Range. I don’t know what they ever found on him, but he was dead when the paramedics got to him. I would say it’s a handful, but not dozens a year.

Thank you for your time Dr. Gervais. Is there anything more you would like to share about high altitude medicine?

Dr. Jack Gervais: I would say probably anybody with any serious cardiac or pulmonary comorbidities who is going to vacation here should really be on oxygen at least at night. That would prevent a huge number of these problems. I actually see a lot of people (locals) who sleep on oxygen at night even if they’re 40 and healthy and don’t really have any issues and they just sleep much better.

And the other thing is you know, especially the people who have lived up in Leadville for 60 years tend to develop a gradually progressive chronic pulmonary hypertension which adds to blood pressure management issues and so that’s an issue we definitely see. So I tell anybody who has any sort of symptoms and is going to be here for a while, “just buy yourself a (oxygen) concentrator, keep it at your house,” that way when they come up for a week vacation every winter they’ve got it and just sleep with O2 every night and avoid all the hassle. And don’t bring your blood pressure cuff on vacation!!

There’s a cardiologist who works over in Vail, he was really convinced that living at altitude is really bad for your chronic blood pressure issues.

Dr. Chris Ebert-Santos: Our interview with three other high-altitude physicians in primary care and cardiology say their standard is “if you’re 50 and you’ve lived here 10 years and you want to live here for another 10 years you should be sleeping on oxygen.”

Rachel Mader is a second-year physician assistant student at Red Rocks Community College. She was born and raised in Colorado Springs and attended Colorado State University where she graduated with a bachelor’s in biology. Before starting PA school, Rachel worked as a Physical Therapy Aide at CSU Health and Medical Center, a CNA at a nursing home, and a Clinical Assistant at Children’s Hospital in Colorado Springs. In her spare time she enjoys spending time with her family, friends, and pets, and eating at new restaurants.