Myasthenia Gravis (MG) is a condition caused by the production of antibodies that block acetylcholine receptors. This blockade of neuromuscular signaling results in rapid muscular fatigue and weakness. Increased activity tends to worsen muscular issues which usually resolve with rest. Prominent symptoms of MG include drooping eyelids, double vision — OMG (ocular myasthenia gravis)– difficulty swallowing, slurred speech, and shortness of breath. Generally, muscles in the face and throat are considered to be the most commonly impacted by Myasthenia Gravis. However, this condition can affect any muscle group throughout the body (1). Gastrointestinal (GI) manifestations such as abdominal pain, recurrent vomiting, and constipation have been reported by individuals with MG. A case presenting to the Summit Medical Center located at 9,100 feet illustrates an unusually severe manifestation:
St. Anthony Summit Medical Center on Peak One Drive in Frisco, Summit County, Colorado, at the foot of Peak One of the Ten Mile Range, enshrouded in snowy mist.
A 70 year old woman was brought to the emergency department (ED) with severe abdominal and chest pain, concerned that she had a dissecting aortic aneurysm. She reported three previous episodes of severe pain in the 2 weeks leading up to the ED visit, all starting in the afternoon, increasing to prostration by 5 pm and resolving with bed rest. Past medical history was significant for myasthenia gravis for which she took azathioprine 100 mg BID (twice daily). Two months previously she had a flare with ptosis and double vision, treated with prednisone 40 mg daily.
Laboratory tests were normal. Imaging showed distended loops of bowel consistent with ileus. She was treated with pain medication and symptoms resolved.
The patient continued to have episodes once or twice a month, including another ED visit, precipitated by treatment with duoneb, which has anticholinergic activity, a tonic water drink, and guaifenesin, both antimuscarinic substances that interact with the cholinergic receptors in the viscera.. Taking pyridostigmine, a cholinesterase inhibitor, led to resolution within 2 hours, marked by “sparkly” sensations in her arms and legs and reactivation of bowel sounds with flatus.
CT scan of patient with intestines diffusely distended with bowel gas.
Until recently, GI symptoms were considered rare in myasthenia gravis. Then a case study in 2001 demonstrated that gastric dysmotility was a common feature among individuals with Myasthenia Gravis (2). Among all the motility dysfunction reported, gastroparesis was found to be a common autonomic feature in MG patients (2). Gastroparesis is the slowing or stopping of movement in the GI tract resulting in delayed gastric emptying. Further research demonstrated that intestinal pseudo-obstruction was considered to be one of the most common GI manifestations of individuals with MG(3,4,5).
In 2007 it was demonstrated that receptors in gut muscles were structurally similar to skeletal muscle receptors, indicating that GI motility could be highly impacted by the presence or lack of acetylcholine (6). Considering that antibody production in Myasthenia Gravis Individuals can decrease acetylcholine binding to receptors, the presence of GI symptoms among other autonomic dysfunction symptoms suggests inadequate treatment which can result in a poor prognosis for these individuals (7).
What was previously considered a rare symptom within a rare condition, is now being proposed as an early identification tool. Taking into account receptor similarity, GI symptoms can be used as early indicators of myasthenia gravis, specifically gastrointestinal dysmotility (8). The case study showed that MG developed less than a decade after the initial onset of gastrointestinal dysmotility symptoms (8). There is a clear need to identify GI symptoms earlier in MG individuals. This will allow for better treatment and improved long-term health outcomes for these individuals.
At altitude, the low barometric pressure causes gaseous distension in normal individuals producing increased flatus (see blog on HAFE). Combined with MG, GI manifestations can be even more severe. Medical providers treating residents of high altitude communities should consider MG in the differential of patients with abdominal complaints and treat recognized MG patients with anticholinesterase medications to control symptoms. None of this patient’s providers were aware of this manifestation of MG, including the neurologist who specializes in MG, the gastroenterologist who performed an upper endoscopy and colonoscopy, the ED staff, the radiologist and the primary care provider. Patients with MG and their providers need to be aware of medications that interact with the cholinergic receptors in all parts of the body and screen for these as possible precipitators of symptoms outside the classic description of the disease.
2. Vernino S, et al. Myasthenia gravis with autoimmune autonomic neuropathy. Auton Neurosci. 2001;88(3):187–192.
3. Pande R, Leis AA. Myasthenia gravis, thymoma, intestinal pseudo-obstruction, and neuronal nicotinic acetylcholine receptor antibody. Muscle Nerve 1999;22:1600-1602
4. Musthafa CP, Moosa A, Chandrashekharan PA, Nandakumar R, Narayanan AV, Balakrishnan V. Intestinal pseudo-obstruction as initial presentation of thymoma. Indian J Gastroenterol 2006;25:264-265.
5. Seretis C, Seretis F, Gemenetzis G, Gourgiotis S, Lagoudianakis E, Pappas A, Keramidaris D, Salemis N. Adhesive ileus complicating recurrent intestinal pseudo-obstruction in a patient with myasthenia gravis. Case Rep Gastroenterol. 2012
6. Mandl, P, Kiss, JP. Role of presynaptic nicotinic acetylcholine receptors in the regulation of gastrointestinal motility. Brain Res Bull. 2007;72:194–200
7. Putri Aaliyah. Autonomic Dysfunciton. Gastroparesis as autonomic manifestation of myasthenia Gravis: A rare case report. Clinical Neurophysiology. 132: 94-95, 2021 8. Alnajjar, S., Idiaquez Rios, J., Fathi, D., Liu, G., & Bril, V. (2022). Gastrointestinal Dysmotility as the First Manifestation of Myasthenia Gravis. Canadian Journal of Neurological Sciences, 1-2.
8. Alnajjar, S., Idiaquez Rios, J., Fathi, D., Liu, G., & Bril, V. (2022). Gastrointestinal Dysmotility as the First Manifestation of Myasthenia Gravis. Canadian Journal of Neurological Sciences, 1-2.
Health care providers and people who live at altitude often believe that living in the mountains protects from altitude related illness. And yes, there are many ways the body acclimatizes over days, weeks, months, and years, as addressed in previous blog entries. However, as a physician who has practiced in high altitude communities for over 20 years, my personal observation that we are still at risk for serious complications was reenforced by a recent publication by Dr. Santiago Ucrós at the Universidad de los Andes School of Medicine in Santa Fe de Bogotá, Colombia. His article, High altitude pulmonary edema in children: a systemic review, was published in the journal Pediatric Pulmonology in August 2022. He included 35 studies reporting 210 cases, ages 0-18 years, from 12 countries.
Consistent with our experience in Colorado, the most common ages were 6-10 years and second most common 11-15 years. I have not seen or read any reports of adults affected. Cases included two deaths, which I have also seen here.
I receive reports on any of my patients seen in urgent or emergency care. Accidents, avalanches, and suicide attempts are what we think of first needing emergency care in the mountains. However, the most common critical condition is Reentry HAPE. This is a form of pulmonary edema that can occur in children who are returning from a trip to lower altitude. Think visiting Grandma during school break. Dr. Ucrós’ review also confirms that all presentations of HAPE (classic, as in visitors, reentry, and HARPE, resident children with no history of recent travel) are more common in males by a 2.6 to 1 ratio. Analysis of time spent at lower altitude before the episode showed a range of 1.6 to 30 days with a mean of 11.3 days. Mean time between arrival and onset of symptoms for all types of HAPE was 16.7 hours. The minimum altitude change reported in a HAPE case was 520 meters (1700 feet), which is the difference between Frisco, CO (Summit County) and Kremmling, CO (Grand County, the next county over). A new form of HAPE in high altitude residents who travel to higher altitude was designated HL-HAPE in this review. A case report will be featured in an upcoming blog interview with a Summit County resident who traveled to Mt. Kilimanjaro.
As with all cases of HAPE, the victims develop a cough, sound congested as the fluid builds up in their lungs, have fatigue, exercise intolerance, with rapid onset over hours of exposure to altitude, usually above 8000 ft or 2500m. Oxygen saturations in this paper ranged from 55 to 79%. My patients have been as low at 39% in the emergency room. Children presenting earlier or with milder cases come to the office with oxygen saturations in the 80’s. An underlying infection such as a cold or influenza is nearly always present and considered a contributing factor. Everyone living or visiting altitude should have an inexpensive pulse oximeter which can measure oxygen on a finger. Access to oxygen and immediate treatment for values under 89 can be life-saving.
The recurrence rate for all types of HAPE is about 20%. Most children never have another episode, but some have multiple. Preventive measures include slower return to altitude, such as a night in Denver, acetazolamide prescription taken two days before and two days after, and using oxygen for 24-48 hours on arrival. Most families learn to anticipate, prevent, or treat early and don’t need to see a health care provider after the first episode.
On January 26, 2023 I met with Dr. Ucrós and other high altitude scientists including Dr. Christina Eichstaedt, genetics expert at the University of Heidelberg in Germany, Dr. Deborah Liptzen, pediatric pulmonologist, and Dr. Dunbar Ivy, pediatric cardiologist, both from the University of Colorado and Children’s Hospital of Colorado, and Jose Antonio Castro-Rodríguez MD, PhD from the Pontifica Universidad Católica in Santiago de Chile.
We discussed possible genetic susceptibility to HAPE and hypoxia in newborns at altitude with plans to conduct studies in Bogotá and Summit County, Colorado.
Louie was excited to get out on the slopes after spending Thanksgiving with family in Vermont. He got tired early and felt his breathing was harder than usual, leaving early to go home and rest. As a competitive skier he thought that was strange. But he was getting over a cold. He could not have imagined that in 24 hours he would be in the emergency room, fighting for his life.
Louie experienced a dangerous condition, set off by altitude, and inflammation from his “cold”, that caused his lungs to fill with fluid. His oxygen saturation was 54 % instead of the normal 92, he had been vomiting and feeling very weak and short of breath. His blood tests showed dehydration, hypoxemia and acute kidney injury. His chest x-ray looked like a snowstorm. He was transferred to Children’s Hospital in Denver and admitted to the intensive care unit.
The diagnosis of Re-entry HAPE was confirmed by echocardiogram showing increased pressures in his lungs. He improved rapidly with oxygen and low altitude.
Re-entry HAPE is not rare, affecting several Summit County children every year. Many do not come to medical attention because after their first episode parents carefully monitor their oxygen and have a concentrator available in their home when they return from travel.
Medical providers may not be aware of this risk, expecting that children living at altitude are acclimatized. (See blog entry on Acclimatization vs. Adaptation, April 17, 2019) Re-entry HAPE seems to occur mostly in children between the ages of 4 and 15. Inflammation, such as a viral respiratory infection, seems to play a role. Trauma may also predispose a returning resident to Re-entry HAPE, as described in our blog post from February 5, 2018, Trauma related High Altitude Pulmonary Edema
Louie agreed to share his story on our blog to help educate medical personnel and families living in the mountains about this dangerous condition. Further research will help define who is at risk.
It took ten years for me to convince high altitude experts that children living in the mountains get high altitude pulmonary edema (HAPE) without leaving home. My observations were published in 2017 in the Journal of High Altitude Medicine and Biology,
High-Altitude Pulmonary Edema in Mountain Community Residents
This week Dr. Jose A Castro-Rodriguez MD PhD ATSF discussed HAPE in children at the 8th World Hypoxia conference in La Paz including the now renamed high altitude resident pulmonary edema (HARPE) in his presentation.
Dr. Castro-Rodriguez emphasized the importance of recognizing the three forms of HAPE, including reentry HAPE when children return to the mountains from vacation, since these can be life threatening.
My work has been cited in articles by pulmonologists Deborah Liptzin and Dunbar Ivy from Children’s Hospital of Colorado and geneticist Christine Eichstaedt and her team at the University of Heidelberg.
At Ebert Family Clinic we give every patient/family a free pulse oximeter. The ability to measure the oxygen saturation of anyone with cough, congestion, or fatigue can facilitate early treatment with oxygen and prevent visits to the emergency room, hospital and intensive care unit.
I recently received first prize for a poster presentation on HARPE at the fall Colorado Medical Society meeting, and second prize for a poster on Trauma and HAPE.
For more information about HAPE, HARPE and Trauma-related HAPE, see previous blog entries.
References
Ebert-Santos C. High-Altitude Pulmonary Edema in Mountain Community Residents. High Alt Med Biol. 2017 Sep;18(3):278-284. doi: 10.1089/ham.2016.0100. Epub 2017 Aug 28. PMID: 28846035.
Giesenhagen AM, Ivy DD, Brinton JT, Meier MR, Weinman JP, Liptzin DR. High Altitude Pulmonary Edema in Children: A Single Referral Center Evaluation. J Pediatr. 2019 Jul;210:106-111. doi: 10.1016/j.jpeds.2019.02.028. Epub 2019 Apr 17. PMID: 31005280; PMCID: PMC6592742.
Liptzin DR, Abman SH, Giesenhagen A, Ivy DD. An Approach to Children with Pulmonary Edema at High Altitude. High Alt Med Biol. 2018 Mar;19(1):91-98. doi: 10.1089/ham.2017.0096. Epub 2018 Feb 22. PMID: 29470103; PMCID: PMC5905943.
Eichstaedt CA, Mairbäurl H, Song J, Benjamin N, Fischer C, Dehnert C, Schommer K, Berger MM, Bärtsch P, Grünig E, Hinderhofer K. Genetic Predisposition to High-Altitude Pulmonary Edema. High Alt Med Biol. 2020 Mar;21(1):28-36. doi: 10.1089/ham.2019.0083. Epub 2020 Jan 23. PMID: 31976756.
Dr. Neale Lange is a leader in sleep medicine who started his medical training in South Africa and now practices Pulmonary and Sleep Medicine for UCHealth in Denver.
Sleep plays a crucial role in cognitive behavior and physical well-being but is often times taken for granted. As Dr. Neale Lange puts it, many people have been taught or trained to devalue sleep in an effort to maximize the time awake to study, get caught up on work, or complete other tasks1. However, research over the years has demonstrated that the toll sleep deprivation plays on the body is significant. Sleep deprivation can lead to impairment in memory, cognition, and emotion, and can lead to chronic medical conditions such as diabetes, heart disease and cancer2. It is also thought that sleep deprivation and hypoxemia are associated with white matter disease in the brain and deep slow wave sleep is what fixes it4.
Dr. Lange states that sleeping at altitude carries its own risks. There is less oxygen in the air, causing overall poor sleep quality, frequent arousals, marked nocturnal hypoxia and periodic breathing.. Additionally, sleeping at altitude can negatively impact our sleep architecture, increasing the amount of light sleep and decreasing the amount of deep slow-wave and REM sleep which plays a key role in memory creation, retention and emotional control and personal behavior3.
In hopes of defining a person’s sleep at altitude Dr. Lange started a sleep lab in Summit County at St. Anthony Summit Hospital, which, as he put it, “opened a can of worms” when he saw how sick and complicated patients’ sleep apnea symptoms were. Time and time again, he saw that when patients who were struggling with sleep apnea were given 2L of supplemental oxygen by nasal cannula, the apnea improved. Additionally, those patients with sleep apnea who descended around 4,000 feet to Denver have improved saturations but may still have sleep apnea. His facility study included baseline tests at two hours without oxygen and then two hours with oxygen while a person slept. He found that although the apnea improved in many, improvements in sleep itself did not always follow.
This left him with the question of: How do we measure “good sleep?” Well, as he states, it is not that simple. Though the obvious answer may be to turn to medications to determine good sleep, this can be misleading. Medications have an amnestic effect on people because when they wake up in the morning, if their memory is blank, they feel that they have had a good night’s rest. But in reality, this is subjective. The true data collected during sleep is objective, so to answer his question of measuring sleep, he turns to a tool of cardiopulmonary coupling (CPC). The SleepImage Ring, looks similar to an Apple Watch and is worn around a patient’s finger throughout the night. Using Bluetooth technology, data is collected and transferred through a smartphone for analysis, providing the patient with a vast amount of data about their sleep.
The SleepImage System is the only FDA approved medical grade technology with the simplicity of a consumer device on the market for use in both children and adults. It is intended for use by a healthcare professional to establish a patient’s sleep quality and aid in evaluation and clinical diagnosis of sleep disorders and sleep disordered breathing, or SDB. It uses CPC technology which is “based on calculations and spectral analysis of cardiovascular- and respiratory data” collected during sleep using continuous “normal sinus rhythm ECG- or PLETH (Plethysmogram from a PPG sensor) signal as the only input requirement.” The output metrics from the SleepImage System include “sleep duration (SD), total sleep time (TST), wake after sleep onset (WASO) and sleep quality (SQI). Measurements related to apnea or sleep disordered breathing (SDB) include an Oxygen Desaturation Index (ODI), an Apnea Hypopnea Index (sAHI), a Respiratory Disturbance Index (sRDI), Central Sleep Apnea Index and the Sleep Apnea Indicator (SAI) that is derived from Cyclic Variation in Heart Rate (CVHR)6. With a PLETH signal including saturations, the SDB data conforms with the American Academy of Sleep Medicine AHI scoring and severity definitions.” Additionally, we can determine how long a patient spends in various sleep stages, including stable, unstable and REM sleep, determine apnea events, and autonomic nervous system activity. The data is generated and presented on the SleepImage Quality Report (shown below). The ring and report are designed as such where you can do individualized, precise sleep medicine. Dr. Lange says “the devil is in the details” referring to the vast amount of information that can be analyzed from this device during one night of sleep.
Currently, the gold standard to monitoring and diagnosing sleep disorders is polysomnography, also known as a sleep study, which records certain body functions as you sleep to determine brain activity, oxygen, heart rate, breathing, as well as eye and leg movements5. It can detect types of sleep apnea and is typically done during an overnight stay in a hospital or other sleep center, which presents a disadvantage taking people out of their natural sleeping environment The cost, time waiting for an appointment and inconvenience deter a large portion of people from partaking in sleep studies.
Dr. Neale Lange explains that this device can change the way we look at our sleep and may provide better insight into a person’s sleep on a greater scale due to the ease of wearing the device over multiple nights, compared to spending one night in a sleep lab for a study. A study done on 65,000 users indicated that there is added benefit to multi-night testing as compared to single night testing. Sleep apnea has been shown to vary from night to night, indicating that single night testing potentially misclassifies 20% of people7. This device provides the ease of multi-night testing for patients, which is a significant advantage and increases accurate diagnosis of sleep disordered breathing. To Dr. Lange, “it is about individualized patient care” and evaluating “the person sitting in front of [him]” which makes this device so valuable. Dr. Lange states that, “living at altitude is a particular challenge, and if people are thinking ahead,” instead of wondering, “how long do I want to live at altitude,” a better question would be, “how can I invest in brain wellness.”
In summary, sleep deprivation, especially at altitude, is an important focus that people should not overlook. At Ebert Family Clinic in Frisco, every patient is asked, “how did you (or your child) sleep last night?” Now, with the SleepImage Ring, we can objectively evaluate our patient’s sleep which can aid in the diagnosis and management of various conditions. We have also found that most patients have over a 60% improvement in sleep apnea using oxygen by nasal cannula alone, without CPAP. “Doc, that’s the best I’ve slept since I got here,” many people say after their first night on oxygen. Dr. Lange and Dr. Ebert-Santos continue to study the effect of high altitude on sleep and present their findings at conferences. They want patients, providers and scientists to know that a simple intervention can improve your brain, heart and body while enjoying life in the mountains.
References
South African Dental Association. (2021, November 25). The sleep disorder spectrum: Mouth breathing to Osa – Dr Neale Lange (WEB126). YouTube. Retrieved December 5, 2021, from https://www.youtube.com/watch?v=agZruGNfFNI
Irish, L. A., Kline, C. E., Gunn, H. E., Buysse, D. J., & Hall, M. H. (2015). The role of sleep hygiene in promoting public health: A review of empirical evidence. Sleep medicine reviews, 22, 23–36. https://doi.org/10.1016/j.smrv.2014.10.001
Wickramasinghe, H., & Anholm, J. D. (1999). Sleep and Breathing at High Altitude. Sleep & breathing = Schlaf & Atmung, 3(3), 89–102. https://doi.org/10.1007/s11325-999-0089-1
Voldsbekk, I., Groote, I., Zak, N., Roelfs, D., Geier, O., Due-Tønnessen, P., Løkken, L. L., Strømstad, M., Blakstvedt, T. Y., Kuiper, Y. S., Elvsåshagen, T., Westlye, L. T., Bjørnerud, A., & Maximov, I. I. (2021). Sleep and sleep deprivation differentially alter white matter microstructure: A mixed model design utilizing advanced diffusion modelling. NeuroImage, 226, 117540. https://doi.org/10.1016/j.neuroimage.2020.117540
Lechat, B., Naik, G., Reynolds, A., Aishah, A., Scott, H., Loffler, K. A., Vakulin, A., Escourrou, P., McEvoy, R. D., Adams, R. J., Catcheside, P. G., & Eckert, D. J. (2021). Multi-night Prevalence, Variability, and Diagnostic Misclassification of Obstructive Sleep Apnea. American journal of respiratory and critical care medicine, 10.1164/rccm.202107-1761OC. Advance online publication. https://doi.org/10.1164/rccm.202107-1761OC
Catherine Atkinson is a second-year Physician Assistant student at Red Rocks Community College in Arvada, CO. She was born and raised in Colorado where she has lived her entire life. She received her undergraduate degree in integrative physiology from The University of Colorado- Boulder. Prior to PA school, she was an ophthalmic technician at Colorado Retina Associates. In her free time, she loves cooking, skiing, playing golf and spending time with her family and friends.
Dr. Gutierrez is originally from Mexico City and attended medical school at Universidad La Salle Medical School. He completed his residency at the University of Miami School of Medicine, Jackson Memorial Hospital and has been Board Certified by the American Board of Obstetrics and Gynecology since 1986. He worked in Mexico City with his father who is also an OBGYN before moving to Summit County in 1998. He says that he dealt with pregnancy at altitude even in Mexico City as a young doctor but now has become even more experienced while practicing at St. Anthony Summit Hospital in Summit County, Colorado. In his career he has delivered more than 7,000 babies.
Gutierrez estimates that about 3% of his patients are visitors to Summit County. Most of these patients are not at full term in their pregnancy and present in the ER with signs of premature labor due to dehydration. Usually, these patients are stabilized and sent to Denver for definitive treatment given St. Anthony Summit Hospital only has a Level 1 nursery (basic newborn care).
The most common conditions that he sees occurring in pregnant women at altitude are pregnancy-induced hypertension (PIH), intrauterine growth restriction (IUGR), and small for gestational age (SGA). Because of this, he says that the main difference of observing pregnancy at altitude is more frequent ultrasounds to monitor the growth of the baby. Luckily, most pregnant women at altitude are very fit and healthy because of the active lifestyle that Summit County encourages. However, some women also have a difficult time restricting their activity level enough to maintain proper growth of the baby. The recommended maximum heart rate during pregnancy is 80% of your maximum heart rate, which can be hard to not exceed in an active pregnant female living at altitude.
Nevertheless, the risk of high altitude pulmonary edema (HAPE), high altitude cerebral edema (HACE), and sleep problems are about the same as in pregnant women not living at altitude. In general, pregnant women past 24 weeks have difficulty sleeping no matter where they live. In addition, if you know you are at high risk for developing HAPE or have a history of HAPE you are just as likely to develop HAPE during your pregnancy as you are not pregnant.
Sleeping with oxygen is recommended and has many benefits for all individuals living at altitude, pregnant women included. However, it likely wouldn’t decrease the number of SGA babies because of the activity level of most individuals as mentioned earlier. A woman’s body increases blood volume, red blood cell count, respiratory rate, and vasodilates blood vessels to accommodate for the growing fetus. This in turn allows the body to compensate well and usually maintain normal oxygen saturation levels at altitude. But Dr. Gutierrez feels eventually it will be recommended for everyone to sleep with oxygen, most people just don’t want to.
Especially with dehydration, he has seen very high red blood cell concentrations. However, these individuals usually only need rehydration and do not suffer any complications. He has not seen a drastic increase in the number of blood clots in pregnant females at altitude even though they are likely at higher risk. But if a pregnant female who is dehydrated and recently traveled to altitude presents with shortness of breath, he definitely puts HAPE and pulmonary embolism (PE) higher on his list of possible diagnoses than he would not at sea level.
An important and simple recommendation is increasing their fluid intake. At altitude you have more insensible water loss and are likely more physically active, which in turn can lead to faster dehydration causing premature labor. Luckily this complication is easily managed with adequate fluid intake. In addition, if you know you are at high risk for developing HAPE it is recommended that you do not travel to altitude, especially later in your pregnancy.
The baby lives in a hypoxic environment in the womb anyway so there are no known advantages to living at altitude while being pregnant, other than the active and healthy lifestyle Summit County promotes.
One of the most challenging cases Dr. Gutierrez has treated was severe maternal respiratory distress during early third trimester due to HAPE. The most definitive treatment was to transport her to a lower altitude, however, they had to stabilize the mother enough to be able to transfer her and her baby. In addition, Summit County does not have a high level nursery to take care of a very premature baby even if they were able to deliver the baby safely to take stress off the mother’s body. He said it was a delicate balance trying to determine what was best and safest for both the mother and the baby.
Bailie Holst is a second-year Physician Assistant student at Red Rocks Community College in Arvada, CO. Bailie was born in Longmont, Colorado and spent her life in Northern Colorado until moving to Minneapolis, Minnesota for her undergraduate studies at the University of Minnesota. She also spent her life traveling throughout the country competing in gymnastics competitions and eventually earning a full-ride athletic scholarship for gymnastics to the University of Minnesota. She finished her gymnastics career and graduated with a Bachelor’s degree in Physiology in 2017. Prior to PA school she worked as a medical assistant in a sports medicine and rehabilitation office in Colorado for two years. In her free time, Bailie now enjoys golfing, traveling, spending time with family, and playing with her brand-new puppy.
The long-awaited results for the Ebert Family Clinic study on sleep at altitude were analyzed in collaboration with Colorado Sleep Institute (CSI). Christine Ebert-Santos, MD, MPS and Tara Taylor, FNP organized and conducted the Overnight Pulse Oximeter Study In Healthy Adults at three elevations, with the support of the local mountain community and the American Embassy in La Paz, Bolivia. The purpose of the study was to evaluate nocturnal oxygen saturation levels in populations living at 3800 m (12,467′), 2800 m (9,186′) and 2500 m (8,202′) and determine treatment recommendations for central apnea and hypoxia. Volunteers were recruited by the clinic from residents in the community and current patients, and by the American Embassy nurse practitioner Annette Blakelee. Informed consent was obtained by the clinic staff and providers. Each participant completed a health questionnaire on length of residence at altitude, medical history and possible symptoms related to higher elevations. Blood pressure, height, weight, and BMI were measured and documented at enrollment. Patients enrolled in study sites for routine care had past Hb/Hct added to the questionnaire. The device (pulse oximeter) was dispensed to the participants with instructions for use. The participants wore the device at night during sleep before returning it to the research staff at the clinic. The results were downloaded from a USB device, recorded onto a spreadsheet, and analyzed by a statistician. If the results were concerning for hypoxia, (<89% for over 20% of the study), participants were asked to repeat the test, completely off any substance (e.g., drugs, alcohol). The study also accounted for factors such as years at altitude and percent of life at altitude to assess potential adaptations to the environment and subsequently, changes in oxygen saturation levels. The goal of the study is to inform providers and residents which symptoms are related to altitude or sleep disorders and recommend treatment that will allow them to feel better and be more active, as well as reduce complications from hypoxia, such as pulmonary and systemic hypertension, fatigue, and daytime drowsiness.
Results of the study concluded that years at altitude, percent of life at altitude, gender, and age do not explain the variance of adaptation to altitude, as measured by time <88% oxygen saturation (SpO2) in these data. The only factor statistically significant in adaptation to altitude was body mass index (BMI). This data provides direction for future studies.
P>0.05 is non-significant. This suggests that there is something else besides percent of the life spent at altitude that explains the level of adaptation participants are experiencing.
Overlapping fit lines (colored) and range estimates (gray) means that the groups are not different. Thus gender cannot explain the difference in adaptation responses.
Tara Taylor FNP had the primary role of reviewing and discussing sleep study results with individuals participating in this study. Tara has worked at the Ebert Family Clinic for over 3 years as a family practitioner, before which she was an intensive care nurse for adults and children for 14 years. She is passionate about sleep issues that occur at high altitude. Tara states that “the most interesting finding was that normal, healthy adults without any comorbidities who are of normal weight and do not have any other medical conditions, had basal oxygen levels <90%, and most had 88-89% basal oxygen. We did see some drops to 85-87% oxygen saturation (SpO2) overnight without any apnea. We checked the length of time spent in different ranges. I found that healthy adults were spending more time below 90% SpO2 than anticipated. We used the index per hour, which gave us a preliminary idea of how many times oxygen increases and decreases.” Based on the results, patients would be notified on any follow up that was needed.
The new Colorado Sleep Institute (CSI) in Frisco will allow patients to receive comprehensive care with more accurate results than can be found at a lower elevation clinic. Dr. Mark Hickey, MD, Board Certified Specialist in Sleep Medicine, and Dr. Ellen Stothard reviewed and interpreted the data collected by Ebert Family Clinic. Dr. Stothard is currently the Research and Development Director at the Colorado Sleep Institute. Her passion lies in conducting sleep research, collecting relevant data, and readily communicating findings, as she believes that good sleep is fundamental for a healthy lifestyle. Dr. Stothard discussed the difference between central versus obstructive sleep apnea and a highly prevalent process called treatment emergent central sleep apnea (TECSA), which is the persistence of central sleep apnea during treatment for obstructive sleep apnea. According to Dr. Stothard, “TECSA is seen when one is treated for obstructive sleep apnea with the continuous positive airway pressure (CPAP), causing a disruption to the central sensing mechanism, resulting in central sleep apnea. Following this phenomenon, patients with obstructive sleep apnea believe that they are resistant to treatment when the CPAP doesn’t improve their symptoms.” These patterns are actually central events which can be helped with decreasing pressure of the CPAP and readjusting air flow. Essentially, CPAP settings should be adjusted based on altitude and elevation, as this is a huge factor influencing nocturnal oxygen saturation levels.
Dr. Stothard has worked with numerous patients receiving CPAP treatment including those at lower altitudes. Since opening her clinic at high altitude, the providers at CSI have noticed that patients tend to feel more fatigue, reporting less relief from treatment with CPAP. Symptoms the patients are experiencing require an individualized approach. “Sleep medicine is so unique,” states Dr. Stothard “and you have to take the time to tailor the treatment and titrate it to perfection to match the patient’s physiology, tolerance for the air, and whether they wear a nasal mask or full-face mask. We spend a lot of time on those specific things in our clinic.”
Dr. Stothard discussed the influence altitude has on conditions such as obesity, explaining that “BMI is a known risk factor for sleep apnea. Someone with a higher BMI will have a different physiology due to its effect on airway collapsibility. Recommendations to reduce sleep apnea are to maintain a healthy weight, which can improve the success of treatment.” Dr. Stothard also spoke about the role of physical therapy in sleep hygiene and how it can help improve sleep, especially in people who have traumatic brain injuries. “Understanding the way sleep facilitates recovery and repair of the body is crucial” and physical therapists can help bridge that gap. Sleep not only allows for the body to restore and re-energize, but also allows for the toxins to be cleansed out from the brain. Moreover, “while we sleep, there is an increase in the interstitial space in the brain allowing the cerebrospinal fluid to flush out chemicals, such as adenosine.” Excess retention of adenosine can cause sleepiness and grogginess acutely, while chronically, it can cause inflammation, fibrosis, and organ damage.
The Overnight Pulse Oximeter Study In Healthy Adults gives us some interesting preliminary information. The CSI and Ebert Family Clinic will be collaborating on future studies to help us understand sleep at altitude in greater depth. For more information on the high prevalence of central apnea at altitude at all ages and the importance of using oxygen at night for residents 50 and older, see previous blog posts on sleep and interviews with local providers Dr. Craig Perrinjaquet and Dr. Peter Lemis.
Arti Kandalam is a second-year physician assistant student at the Red Rocks Community College Physician Assistant Program in Arvada, CO. Arti was born and raised in Sugar Land, TX and lived there until graduating high school. She then moved to Austin, TX to attend the University of Texas in pursuit of her Bachelors in English degree. Shortly after, she obtained her Masters in Biomedical Sciences at the University of Houston in Victoria. She moved back to Sugar Land, TX, where she worked as a Medical Assistant and Scribe at Texas Pain Centers for 4 years. In her free time, Arti enjoys dancing/teaching Bollywood choreography, biking, and hiking.
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.
Dr. Margot Daly DVM, CCRP, CVA, of the Frisco Animal Hospital in Frisco, CO, graduated from the University of California – Davis in 2013, and has worked in general practice, emergency practice, and most recently in specialty practice as a full-time rehabilitation and sports medicine veterinarian. Prior to veterinary school, she studied Sociology at UC Berkeley, and had a career as a professional equestrian, which led to an interest in orthopedics, biomechanics, and physical rehabilitation. Following graduation, she received the Certified Canine Rehabilitation Practitioner designation from the University of Tennessee – Knoxville, and the Certified Veterinary Acupuncturist designation from the Chi Institute in Reddick, Florida. She has been with the Frisco Animal Hospital for a year and a half, and when she is not working, she can be found riding a horse or one of her many bicycles, fostering dogs and kittens, reading books, skiing, or traveling somewhere new!
We interviewed Dr. Daly on her advice for canine high country health, winter dog gear, common winter injuries, and winter activities to participate in with your dog.
One of the most common things to be aware of is canine “weekend warrior syndrome.” Dog owners must be sure their dogs are fit enough to participate in physically intense weekend activities. Many dogs only go out in their yard or take a few short walks during the week and then go on big hikes, back country ski trips, or long mountain bike rides on the weekends. Unfortunately, during the high intensity activity the dog’s adrenaline is high and the dog won’t show signs of fatigue, yet the next day with dog will feel awful and be extremely sore. It is comparable to a human doing cross fit only once per week … [imagine] how he or she would feel the next day. To avoid this phenomenon, ensure your dog is fit enough by practicing 30-60 minutes of moderate exercise at least three times per week, which can include 30 minutes of jogging or 60 minutes of active walking. If your dog is doing less than that during the week, it is important to be thoughtful of what you are asking of your dog or what you are giving them the opportunity to do over the weekend. Unfortunately, a fun weekend can become overly taxing on your dog very quickly.
Signs your dog may have done too much over the weekend include not wanting to go up or down stairs, refusing to jump in and out of the car, or not wanting to get up or down from the couch. Your dog may not necessarily be limping since they are more likely to have general full-body fatigue, aches, and soreness. Your dog should still eat and drink normally, and if they aren’t that is reason to call your vet.
Winter Clothing & Gear
Booties: Dog clothing can be helpful as dogs can get cold just like humans do during outdoor winter activities. Booties can be advantageous during both summer and winter activities. The best policy is to pay attention to your dog’s behavior to determine how necessary booties are. Some dogs make it clear that they are uncomfortable in the snow and slush by holding their paws high in an alternating fashion, sitting down, or refusing to walk. Some dogs are more sensitive than others and some have a higher tolerance for the cold than others.
Dog booties!
The key to booties is acclimating your dog over a week or so before taking the booties out on an adventure. The best way to do this is to put your new booties on your dog in your house and then give them a treat or play with their favorite toy. This will help reinforce the booties and make them a fun experience for your dog! This may take several days before the dog will tolerate the booties and walk around comfortably in them. Essentially, don’t wait until the morning of the big hike to put the booties on your dog for the first time. Another strategy is to start with lightweight booties made of felt with one Velcro strap. These are a lightweight cheap option and are the same booties sled dogs on the Iditarod use. It is best to buy a few sets of these to start as some will inevitably get lost. If you find that your dog requires something more substantial, Dr. Daly recommends RuffWear boots which have a heavy rubber sole. Beware these booties may cause difficulty for a dog with mobility issues where heavy booties may impair the dog’s ability to walk safely. Custom booties are also an option and are recommended for dogs with atypically shaped feet such as greyhounds. A company called TheraPaw will coordinate with your vet to get measurements of your dog’s feet and make custom booties.
If your dog is totally intolerant of booties but could benefit from them, you can try musher wax. It provides a slightly waterproof barrier between your dog’s paws and the roads. It also helps prevent ice balls in dogs with a lot of feathering on their paws or between their toes. Put the wax on right before your take your dog outside and wipe the dog’s paws as soon as you get home. This can help protect dogs who have a lot of road time to protect them from road salt, sand, and ice chemicals.
Jackets: Dr. Daly confirms that there are dogs that may benefit from a jacket especially when participating in winter hiking or backcountry skiing. If you see your dog shivering, hunching their back, or crouching their neck and shoulders, your dog is likely cold and would benefit from a jacket. When choosing a jacket, it is imperative that you choose a jacket that has a full chest and short sleeves vs one that just has a strap across the chest. This ensures that the snow will slide off the chest and not become trapped against the dog’s skin. It is hard for a dog to overheat in the winter, but it is a good idea to provide layering for your dog. Most importantly, do not choose a cotton fabric, but a fabric that will wick and dry quickly such as fleece, soft shell, or a technical fabric. If your dog’s jacket becomes wet or soaked, it is important to take it off, because a wet jacket is no longer providing warmth and will end up making your dog colder.
Goggles: There are a large number of canine patients with eye problems related to the UV light exposure at high altitude. In particular, pannus, an eye condition exacerbated by UV light, is common in dogs living at high altitude due to more UV exposure and increased UV reflection off snow. This immune-mediated condition affects the cornea and causes pink or grey granular tissue to grow from the lateral cornea toward the medial cornea. It is a type of chronic superficial keratitis that certain breeds, specifically German shepherds, are more prone to. For this reason, goggles are recommended for dogs living at high altitude especially if the dog is a high risk breed or if they are already diagnosed with pannus. Weekend warriors are at a much lower risk of developing pannus and goggles are not as strongly recommended. As with dog booties, dogs must be acclimated to goggles and the goggles reinforced with treats or play time. It is not recommended to try out goggles for the first time out on the mountain. Aim for about a week of acclimation around the house and neighborhood so your dog tolerates the equipment well. Dr. Daly has had good luck with RexSpecs which do not require a vet to measure the dog, but she is always happy to help owners measure their dogs.
Sunscreen: Surprisingly, canine sunburn is rare, even at high altitude. If it does occur, the burn is normally anywhere the dog has thin to no hair or pink to white skin. Most commonly it occurs on the nose and belly, especially if the dog prefers to lounge on its back in the sun. Mineral-based sunscreens with an active ingredient of titanium dioxide, such as California Baby Brand Sunscreen, are recommended. After putting sunscreen or any ointment on a dog’s nose it is a good idea to immediately give him or her a treat or chew toy to avoid the dog licking the ointment right off.
Prevention at High Altitude
The one best thing you can do to make sure your pet stays healthy and happy at altitude is to ensure adequate hydration. Dr. Daly does not recommend supplemental electrolytes but encourages owners not to depend on mountain streams, rivers, lakes, snow, or puddles to provide adequate hydration for active high country dogs. The high country has giardia and leptospirosis in natural water sources. Giardia can cause gastrointestinal symptoms, and leptospirosis can cause liver and kidney failure as well as having the potential to be transmitted to humans. Bring as much water for your dog as you do for yourself. If you bring one liter then also bring one liter for your dog. Signs your dog may be dehydrated include lethargy, decreased appetite, odd behavior, head-shaking, crying out, or barking. Dogs normally tend to drink more water while at altitude, and this behavior is only concerning if the dog has blood in the urine, appears to be in pain while urinating, or is having accidents in the house when the dog was previously housetrained.
Lastly, if you go camping with your dog it is imperative that you bring your dog’s daily medications with you and not skip a day simply because you are camping. Chronic medications can’t be skipped for even one dose.
Common High Altitude Diagnoses
Dr. Daly sees many recreational injuries and ACL tears between February and April. During this time of year, the snow has a crusty top layer with soft snow underneath. This leads to dogs punching through the top layer and injuring themselves when the soft snow underneath gives way. This post-holing causes many ligament strains and tears this time of year. In the beginning of winter when the conditions are predominantly slippery and icy, she sees wrist and toe strains and sprains from dogs trying to grip with their feet.
Another common injury are lacerations from back country skis. Many people enjoy taking their canine companion back country skiing but fail to train the dog to stay behind them while cruising down the slope. As a result, many dogs end up with lacerations from running in front of or beside their owner and making contact with their owner’s skis. This can lead to lacerations on the dog’s lower legs including around their tendons. It is also important to teach your dog to stay behind you if they come mountain biking. Many dogs end up with injuries from running in front of or beside their owner’s mountain bikes.
Head pressing
Acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), re-entry HAPE, or high altitude cerebral edema (HACE) are exceedingly rare in dogs. The only situation which may predispose a dog to breathing problems is one coming from sea level with underlying cardiac or pulmonic pathology, such as heart failure or a pulmonary contusion. When coming from sea level with an older dog or one with an underlying comorbidity, it is recommended to stop in Denver for 2-3 nights to let the dog acclimate to the altitude and resultant lower oxygen concentration. Dogs can be prescribed home oxygen concentrators, but these should only be used under the supervision of a veterinarian as they require a specific home kennel or tubing being sewn into the dog’s nare. If your dog falls into a high risk category, Dr. Daly describes “head pressing” as an alarm sign requiring an emergency call to a local vet. This is described as a dog leaning headfirst into a wall, furniture, or other upright object as though it is using the object to hold its head up. Other concerning signs include severe lethargy, vomiting or diarrhea that does not resolve within 24 hours, or respiratory distress of any kind.
Strengthening & Exercise
Most dogs will benefit from some degree of core and hind limb strengthening, as well as exercises to improve proprioception, or body awareness. The stronger and more coordinated the dog is, the lower risk of injury, even with high impact activities. Additionally, dogs can benefit from a personalized exercise program based on their confirmation, for example a long back or short legs, and pre-existing injuries. Dr. Daly’s background in sports medicine gives her a unique viewpoint allowing her to assess any dog and provide a program to prevent future and, more importantly, repeat injuries. If an owner is hoping that his or her companion can return to hiking 14ers after a ligament tear, then a home exercise program is imperative. Plans generally require about 20 minutes of treatment averaging three times a week and incorporating everyday activities such as stairs and working the dog on alternative surfaces. This ensures dog owners don’t necessarily have to invest in additional equipment.
Are there any winter dog sports clubs you recommend?
Dr. Daly has found that many types of active dogs enjoy the variety of mushing sports that can be done in the winter. These include everything from single or double dog skijoring, bikejoring, and canicross (which is a version of cross country running with your dog), all the way to dogsledding with two or more dogs. She is a part of the Colorado Mountain Mushers which is a great place to start for anyone interested in exploring these activities. The club consists of retired professional veterans to amateur mushers and is a friendly, welcoming, all-inclusive group with abundant resources and advice. The club usually runs about four events per year (COVID pending) and can help you learn some new ways to connect with your canine companion, Huskies not required!
Courtney Zak is currently in her second year of PA school at Red Rocks Community College in Arvada, CO. She is a member of the class of 2021 graduating in November. She attended the University of North Carolina at Chapel Hill in Chapel Hill, NC for her undergraduate degree in American Studies. She then completed an Occupational Therapy Assistant (OTA) program at Cape Fear Community College in Wilmington, NC. She practiced five years as an OTA working primarily with the geriatric population helping rehab people with various orthopedic injuries, strokes, heart attacks, and general deconditioning. After working up to management, Courtney decided she wanted to gain more medical insight and expand her scope of practice, so she decided to pursue a career as a physician assistant. Courtney now lives in Golden with her husband Jack, three dogs Brooks, Arlo, and Chloe, and her horse, Cannon. She enjoys horseback riding, hiking, paddle boarding, camping, and mountain biking in her free time.
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.
