Acute mountain sickness (AMS) is a condition that can occur when individuals ascend to high altitudes rapidly, typically above 2,500 meters (8,200 feet). The symptoms of AMS are due to the body’s struggle to adapt to the decreased oxygen levels at higher elevations. More specifically, the symptoms are caused by cerebral vasodilation that occurs in response to hypoxia, in an attempt to maintain cerebral perfusion.1
The typical symptoms of AMS include headache, nausea, vomiting, anorexia, and fatigue. In children the symptoms are less specific including increased fussiness, crying, poor feeding, disrupted sleep, and vomiting. Symptom onset is usually 6-12 hours after arrival to altitude but this can vary.
AMS affects children, adults, males and females equally, with a slight increased incidence in females. It is difficult to believe, but physical fitness does not offer protection against AMS. However, people who are obese, live at low elevation, or undergo intense activities upon arrival to elevation are at increased risk.1
Treatments for Acute Mountain Sickness
Descending
Descending and decreasing altitude is a vital treatment for people with severe symptoms of AMS. By decreasing altitude there will be more oxygen in the air and symptoms will not be as severe..2
Oxygen
Since the main cause of AMS is hypoxia, oxygen supplementation is an effective treatment when descent is not wanted or possible. Supplemental oxygen even at .5L to 1L per hour can be effective in reducing symptoms.1 It can be prescribed for short periods of time or to be used only during sleep In the central Colorado Rockies, this may be a practical solution for “out of towners” who have traveled up to the town of Leadville (10,158’/3096m) for vacation, but in an austere environment supplemental oxygen may not be a reasonable treatment option. There should be symptomatic improvement within one hour.
Acetazolamide
Acetazolamide is a carbonic anhydrase inhibitor which causes increased secretion of sodium, potassium, bicarb, and water. This mechanism of actions lends beneficial to the treatment of AMS because it decreases the carbonic anhydrase in the brain. 3There is evidence to support the use of acetazolamide in the prevention of AMS, but minimal evidence pointing towards it’s role in treatment. Dosing is inconsistent but is usually prescribed at 125-250mg BID.
Hyperbaric Therapy
Many people consider hyperbaric chambers to be large structures in hospitals, however there are portable and lightweight hyperbaric chambers that can be used in austere environments or during expeditions. The mechanism of action of hyperbaric therapy is a simulated decrease in elevation, of approximately 2500 meters. These chambers will remove symptoms within approximately one hour of use but symptoms are likely to return. They are useful in the field but not frequently required in a hospital setting.1
Lynde Tucker is a third year medical student who grew up in Lake Tahoe California, and moved to Colorado for medical school. She is grateful for the opportunity to be back living in the mountains and working in a mountain community.
My love for hiking developed during my childhood explorations of the breathtaking landscapes of the Sierra Nevada. As I ventured into the rugged mountains and hiked along scenic trails, I couldn’t help but feel a deep connection with nature. However, my passion for hiking was not without its moments of caution. On several occasions, I witnessed the awe-inspiring yet intimidating power of lightning storms dancing across the vast mountain skies. These encounters instilled in me a profound curiosity about the risks associated with lightning strikes in high-altitude regions.
When I moved to Colorado for PA school, my awareness of the dangers posed by lightning strikes grew even stronger. The dramatic topography and frequent thunderstorms in Colorado amplify the risk for individuals exploring high-altitude areas. It was during my last clinical rotation at a burn unit that I had the opportunity to care for several patients who had been struck by lightning. Witnessing the effects firsthand fueled my determination to educate the public about the actionable steps they can take to stay safe during lightning storms.
Lightning strikes
Lightning possesses an immense amount of energy, with a voltage of over 10 million volts (in comparison, most car batteries measure 12.6 V).1 Additionally, a lightning bolt reaches incredibly high temperatures, reportedly up to 30,000 Kelvin (53540.33 F).1 Lightning injuries occur in different ways, including as direct strikes, side splash, contact injuries, or ground current.
Direct strikes are uncommon, accounting for only 5% of cases, and happen when a person is directly struck by lightning.2
Contact injuries occur when a person touches an object that is struck by lightning. 2
Side splash injuries occur when the current jumps or “splashes” from a nearby object and then follows the path of least resistance to reach the individual. These injuries make up about 1/3 of all lightning related injuries. 2
Ground current is the most prevalent cause of injury, accounting for half of all cases, and occurs when lightning strikes an object or the ground near a person and subsequently travels through the ground to reach the individual. 2
In Colorado, an average of 500,000 lightning flashes hit the ground each year. Based on data since 1980, lightning causes 2 fatalities and 12 injuries per year throughout the state.3According to data since 1980, lightning causes an average of 2 fatalities and 12 injuries annually throughout the state.3 Colorado ranked third in the United States for the number of lightning fatalities between 2005 and 2014, as depicted in Figure 1.
Fig. 1. Lightning fatalities by state. 3
The high number of injuries attributed to lightning in Colorado can be influenced by several factors. One of these factors is the easy access to high elevation terrain, such as 14ers (mountains with a peak elevation of at least 14,000 feet). This accessibility allows inexperienced outdoor enthusiasts to venture into potentially dangerous situations due to their lack of knowledge and preparation.
For instance, individuals who are not familiar with summer weather patterns may embark on a hike above the tree line late in the day, underestimating the risk of a storm forming. This lack of understanding puts them in an exposed and perilous position should adverse weather conditions arise.
Even with thorough preparation and extensive knowledge of weather patterns, it is still possible to find oneself in a situation where you have to weather a storm. Given that a significant proportion of Colorado’s hiking trails are located above the tree line, where appropriate shelter is sparse, hikers are more susceptible to lightning strikes in these exposed areas.
Pathophysiology of Lightning Strike Injuries
The overall ratio of lightning injuries to deaths is 10:1 and there is a 90% chance of sequelae in survivors.4 The primary mechanism of injury in lightning strikes is the passage of electrical current through the body. The high voltage and current can cause tissue damage through several mechanisms, including thermal injury, electrical burns, and mechanical disruption of tissues. The severity of the injury depends on factors such as the voltage and current of the lightning bolt, the duration of contact, and the pathway the current takes through the body.
Lightning strikes can cause various types of injuries, with cardiac and respiratory arrest being the most common fatal complications.5 The path of least resistance determines the flow of electricity through different organs in the body, with nerves being the most conductive, followed by blood, muscles, skin, fat, and bone. 5 When lightning strikes, the electrical surge can induce cardiac arrest and cessation of breathing by affecting the medullary respiratory center. As a result, most patients initially present with asystole and may progress to different types of arrhythmias, commonly ventricular fibrillation. 5
Interestingly, there have been case reports documenting successful resuscitation of lightning strike victims who were initially apneic and pulseless for as long as 15 to 30 minutes. 5This has led to the recommendation that in the immediate aftermath of a lightning strike, individuals who appear to be dead should be prioritized for treatment.
Superficial skin burns are experienced by around 90% of lightning strike victims, but deep burns are less common, occurring in less than 5% of cases. A characteristic skin manifestation of a lightning strike is the Lichtenberg figure, which is considered pathognomonic. Neurological symptoms can also occur, including keraunoparalysis, which is a transient paralysis affecting the lower limbs more than the upper limbs. This paralysis is often accompanied by sensory loss, paleness, vasoconstriction, and hypertension, and is thought to result from overstimulation of the autonomic nervous system, leading to vascular spasm. In most cases, this paralysis resolves within several hours, but in some instances, it may last up to 24 hours or cause permanent neurological damage. 5
Additionally, it is common for lightning strike victims to have a perforated tympanic membrane (eardrum) or develop cataracts immediately following the incident. These injuries to the ear and eyes are associated with the intense energy of the lightning discharge.6
What can hikers do to stay safe?
Preparation
Monitor weather forecasts: Stay updated on weather conditions before engaging in outdoor activities, especially in areas prone to thunderstorms. Pay attention to thunderstorm warnings or watches issued by local authorities. Having a mobile or handheld NOAA Weather Radio All-Hazards (NWR) can also be helpful as it can transmit life-saving weather information at a moment’s notice.
In Colorado most thunderstorms develop after 11 am, so it is best to plan your trip so that you are descending by late morning.7Fig. 2 shows number of lightning fatalities by time of day in Colorado between 1980 and 2020. The vast majority take place after the 11 am threshold.
Fig. 2 Lightning fatalities in Colorado by time of day3
What to Do If Caught in a Storm
If you can hear thunder, you are close enough to be struck by lightning. Lightning can strike up to 25 miles away from the storm. 7 Once you hear thunder, if possible quickly move to a sturdy shelter (substantial building with electricity or plumbing or an enclosed, metal-topped vehicle with windows up). Avoid small shelters, such as picnic pavilions, tents, or sheds. Stay sheltered until at least 30 minutes after you hear the last clap of thunder.
Fig 3. Areas to avoid when sheltering from lightning.
If you are outdoors and cannot reach a suitable shelter, avoid open areas, hilltops, and high places that are more exposed to lightning strikes. Seek lower ground and stay away from tall objects, such as trees, poles, or metal structures. Bodies of water, including lakes, rivers, pools, and even wet ground, are conductive and increase the risk of a lightning strike. Move away from these areas during thunderstorms. Separate group members by at least 20 ft as lightning can jump up to 15 feet between objects.
If a strike is eminent (static electricity causes hair or skin to stand on end, a smell of ozone is detected, a crackling sound is heard nearby), the current recommendation is to assume “lightning position”, pictured in Fig. 4.
Fig. 4. Lightning position8
To potentially reduce the risk of ground current injury from an imminent lightning strike, another strategy is to insulate oneself from the ground. This can be done by sitting on a pack or a rolled foam sleeping pad. However, it’s important to note that this and the lightning position should be considered a strategy of last resort and not relied upon as the primary means of prevention. Maintaining this position for an extended period can be challenging, and it’s crucial to prioritize seeking proper shelter and following established lightning safety guidelines to minimize the overall risk of injury. 5
Case Study
25 YO F presents to the Burn Unit as a transfer from Cheyenne Regional Medical Center s/p lighting strike. Patient (pt) was caught in a thunderstorm on a hike and sheltered under a tall tree. Suddenly, she felt like she was being lifted up into the air and then dropped. Pt had a brief (<5 sec) loss of consciousness (LOC). When she woke up, she was completely numb and couldn’t move any of her extremities. Witness (friend) states the lightning splashed from the tree to the pt. Pt denies hitting her head with the fall. She denies taking blood thinners. She has no past medical history (PMHx) or past surgical history (PSHx).
Physical exam
Neuro: AOX4, No CN deficit on exam, LE paralysis resolved, LE paresthesia improving but still present
HEENT: L ruptured tympanic membrane, hearing loss on L side
CBC, CMP, troponin were all WNL. Serum hCG negative. CK mildly elevated (222)
EKG showed NSR.
CXR, CT brain, and c-spine neg for acute injury
She was admitted to the UC Health burn center for observation with tele. Her lab work and vitals remained stable throughout her hospitalization. She was evaluated by the trauma team with a negative trauma work up. The day of discharge, she was tolerating a regular diet, ambulating and sating well on room air. She was deemed appropriate for discharge home without patient audiology and ophthalmology follow up.
References
1. US Department of Commerce N. Understanding lightning science. National Weather Service. April 16, 2018. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-science-overview.
2. Cooper MA, Holle RL. Mechanisms of lightning injury should affect lightning safety messages. 21st International Lightning Detection Conference. April 19-20, 2010; Orlando, FL.
3. US Department of Commerce N. Colorado Lightning statistics as compared to other states. National Weather Service. March 4, 2020. Accessed July 7, 2023.https://www.weather.gov/pub/Colorado_ltg_ranking.
4. US Department of Commerce N. How dangerous is lightning? National Weather Service. March 12, 2019. Accessed July 8, 2023. https://www.weather.gov/safety/lightning-odds.
5. Chris Davis, MD; Anna Engeln, MD; Eric L. Johnson, MD; Scott E. McIntosh, MD, MPH; Ken Zafren, MD; Arthur A. Islas, MD, MPH; Christopher McStay, MD; William R. Smith, MD; Tracy Cushing, MD, MPH. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Lightning Injuries: 2014 Update. WILDERNESS & ENVIRONMENTAL MEDICINE. 2014; 25, S86–S95
6. Flaherty G, Daly J. When lightning strikes: reducing the risk of injury to high-altitude trekkers during thunderstorms. Academic.oup.com. Accessed July 8, 2023. https://academic.oup.com/jtm/article/23/1/tav007/2635599.
7. NWS Colorado Offices – Boulder G. Colorado Lightning Awareness Week june 19-25, 2022. ArcGIS StoryMaps. June 25, 2022. Accessed July 8, 2023. https://storymaps.arcgis.com/stories/11d021f1b800429a869ead2dc32c0f96.
8. McKay B and K. How to survive A lightning strike: An illustrated guide. The Art of Manliness. April 25, 2022. Accessed July 8, 2023. https://www.artofmanliness.com/skills/outdoor-survival/how-to-survive-a-lightning-strike-an-illustrated-guide/.
Sophia Ruef is a Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up on the central coast of California and earned her Bachelor of Science degree inBiology with a concentration in anatomy and physiology from Cal Poly San Luis Obispo. She worked as an EMT and a tech in the Bay Area after her undergraduate education. In her free time, she enjoys hiking, backpacking, canyoneering, and spending time with family and friends.
Often, at high altitude we hear complaints of gas pain and increased flatus in our infant population. Parents often wonder, are we doing something wrong? Is my child reacting to breastmilk, or showing an intolerance to certain foods? Actually there is another explanation for increased flatus and gas pain in the high-altitude region of Colorado.
The term HAFE was coined by Dr. Paul Auerbach and Dr. York Miller and published in the Western Journal of Medicine in 1981. Their discovery began In the summer of 1980, when the two doctors were hiking in the San Juan Mountains of Colorado on a quest to summit three 14ers. During their ascent they noticed that something didn’t smell right! As the pair continued to emit noxious fumes, they began to put their scientific brains to work and discovered HAFE. The symptoms include an increase in frequency and volume of flatus, or in other terms an increase in toots! We all have familiarity in watching our bag of potato chips blow up when reaching altitude or our water bottle expanding as we head into the mountains. This reaction is due to a decrease in barometric pressure. Based on Boyle’s law, decreased barometric pressure causes the intestinal gas volume to expand, thus causing HAFE (Skinner & Rawal, 2019).
To my surprise, a gas bubble the size of a walnut in Denver, Colorado (5280 ft) would be the size of a grapefruit in the mountain region of Summit County, CO (8000+ ft)! Trapped gas is known to lead to discomfort and pain. The use of simethicone may have merit in mitigating the effects of HAFE. Simethicone works by changing the surface tension of gas bubbles, allowing easier elimination of gas. This medication, while benign, can be found over the counter and does not appear to be absorbed by the GI tract (Ingold, C. J., & Akhondi, H., 2022).
While this phenomenon may not be as debilitating as high-altitude pulmonary edema (HAPE), it deserves recognition, as it can cause a significant inconvenience and discomfort to those it inflicts. As the Radiolab podcast explained in their episode The Flight Before Christmas , expelled gas in a plane or car when driving up to the mountains can be embarrassing. While HAFE can be inconvenient, it is a benign condition and a matter of pressure changes rather than a disease or pathological process. We would love to talk more about HAFE at Ebert Family Clinic if you have any questions or concerns!
A bald eagle flies toward its nest atop a bare lodgepole pine.
As always, stay happy, safe, and healthy 😊
Taylor Hollingsworth is finishing her final semester as a family nurse practitioner (FNP) student at Georgetown University. Originally from the east coast, Taylor plans to start her FNP career in North Carolina close to family. She has a passion for pediatric and family wellness and has worked as a pediatric intensive care unit nurse for 6 years! In her free time, Taylor loves to hike, fly fish, run, and spend time with her fiancé Logan.
References
Auerbach, P. & Miller, Y. (1981). High altitude flatus expulsion. The Western Journal of Medicine, 134(2), 173-174.
From backpacking and camping to skiing and snowboarding, there are plenty of activities outdoors in the Colorado high country. If you find yourself wandering around and lost without food in the mountains, there are several wild plants that you can eat.
However, before you consume the delectable greens, there are a few precautions to take.
Moose shopping
Do not eat any wild plants unless you can positively identify them. There are iOS and Android apps that you can download prior to your hike to help distinguish plants, such as PictureThis and NatureID.
Be aware of environmental factors such as pollution or animal waste. Avoid popular wild animal gathering areas.
Make sure you’re not allergic to the plant by rubbing it against your skin and observing for a reaction. If so, do not eat the plant. Before ingesting a large quantity, eat a small amount and check for a reaction.
It may be difficult to cook if you did not come prepared with a portable stove, pots, and water, which could limit ways to enjoy vegetation. Here is a list of edible plants, how to identify them, where can they be found, and which part you can eat.
Wild plants
Dandelions (Taraxacum officinale): yellow ray florets that spread outward from center with toothy, deep-notched, hairless basal leaves and hollow stems. They can be found everywhere and anywhere. Every part of the dandelion plant is edible including the leaves and roots.
Pineapple Weed/ Wild Chamomile (Matricaria discoidea): the flower heads are cone-shaped and yellowish-green and do not have petals. Often found near walking paths and roadsides, harvest away from disturbed, polluted areas. If you’re feeling anxious about being lost, pineapple weed promotes relaxation and sleep and serves as a digestive aid.
Fireweed (Epilobium angustifolium): vibrant fuchsia flowers. Grows in disturbed areas and near recent burn zones. Eat the leaves when they are young as adult leaves can stupefy you. Young shoot tips and roots are also edible.
Wild onions (Allium cernuum): look for pink, lavender to white flowers with a strong scent of onion. They grow in the subalpine terrain and are found on moist hillsides and meadows. Caution: do not confuse with death camas. If it doesn’t smell like an onion and has pink flowers, it is not likely an onion.
Cattails (Typha latifolia or Typha angustifolia): typically 5-10 feet tall. Mature flower stalks resemble the tail of a cat. Grow by creek, river, ponds, and lakes. This whole plant is edible, from the top to the roots. Select from pollution-free areas as it is known to absorb toxins in the surrounding water.
Wild berries:
Wild strawberries (Fragaria virginiana): they are tiny compared to store-bought. Can be identified by their blue-green leaves; small cluster of white flowers with a yellow center; and slightly hairy, long and slender red stems.
Huckleberries (Vaccinium spp): They grow in the high mountain acidic soil and flourish in the forest grounds underneath small, oval-shaped, pointed leaves. They resemble blueberries and have a distinguishable “crown” structure at the bottom of the berry. They can be red, maroon, dark blue, powder-blue, or purple-blue to almost black, and they range from translucent to opaque.
Oregon grapes (Mahonia aquifolium): powder-blue berries, resembling juniper berries or blueberries, with spiny leaves similar to hollies that may have reddish tints.
Fun fact: The roots and bark of the plant contain a compound called berberine. Berberine has antimicrobial, antiviral, antifungal, and antibiotic properties.
Mushrooms
True morels (Morchella spp.): cone-shaped top with lots of deep crevices resembling a sponge. They will be hollow inside. A false morel will have a similar appearance on the outside but will not be hollow on the inside and are toxic. Morels are commonly found at the edge of forested areas where ash, aspen, elm, and oak trees live. Dead trees (forest wildfires) and old apple orchards are prime spots for morels.
Porcini (Boletus edulis): brown-capped mushrooms with thick, white stalks. Found at high elevations of 10,500 and 11,200 ft in areas with monsoon rains and sustained summer heat.
There are many more edible plants, flowers, berries, and mushrooms in the mountains. These are just 10 that can be easily identifiable and common in the Western Colorado landscapes. I recommend trying out the apps listed above and reading “Wild Edible Plants of Colorado” by Charles W. Kane, which includes 58 plants from various regions, each with details of use and preparation. Hopefully this post made you feel more prepared for your next adventure.
Resources:
Davis, E., 2022. Fall plant tour: Frisco, CO | Wild Food Girl. [online] Wildfoodgirl.com. Available at: <https://wildfoodgirl.com/2012/eleven-edible-wild-plants-from-frisco-trailhead/> [Accessed 10 July 2022].
McGuire, P., 2022. 8 Delicious Foods to Forage in Colorado | Wild Berries…. [online] Uncovercolorado.com. Available at: <https://www.uncovercolorado.com/foraging-for-food-in-colorado/> [Accessed 10 July2022].
Rmhp.org. 2022. Edible Plants On The Western Slope | RMHP Blog. [online] Available at: <https://www.rmhp.org/blog/2020/march/foraging-for-edible-plants> [Accessed 10 July 2022].
Lifescapecolorado.com. 2022. [online] Available at: <https://lifescapecolorado.com/2014/01/edible-plants-of-colorado/> [Accessed 10 July 2022].
Pfaf.org. 2022. Plant Search Result. [online] Available at: <https://pfaf.org/user/DatabaseSearhResult.aspx> [Accessed 10 July 2022].
Cindy Hinh is a second-year Physician Assistant student at Red Rocks Community College in Arvada, CO. She grew up in southern Louisiana and received her undergraduate degree in Biology from Louisiana State University. Prior to PA school, she was a medical scribe in the emergency department and an urgent care tech. In her free time, she enjoys baking, cooking, going on food adventures, hiking, and spending time with family and friends.
Have you thought of what it would be like living in the mountains year-round? Medical professionals find it is important to look at what living at high elevations can do to the human body. One activity heavily affected is sleep. As mentioned in previous blog posts, visitors often have trouble falling asleep, staying asleep, and feeling rested in the morning. A recent study published in Physiological Reports measured the effects of sleeping patterns at high elevation. The participants experienced a simulated elevation inside a hyperbaric chamber. This mimicked sleeping at elevations of 3000 meters (9,842 feet) and 4050 meters (13,287 ft) for one night and then sleeping at sea level for several nights to establish a baseline for the research participants. Participants exercised for 3 hours in the hyperbaric chamber allowing researchers to observe how the lower oxygen concentrations affected their ability to perform strenuous tasks. The group that slept in a simulated 4050 meter environment had an increased heart rate that was 28% higher and an oxygen saturation 15% lower than the 3000 meter participants. When comparing sleep itself, the group at 4050 meters had 50% more awakening events throughout each night. This goes along with previous research on this blog that states that people who sleep at high altitude complain of insomnia and frequent awakening when first arriving at high elevation.
These numbers increase even more dramatically when compared to participants at sea level. Related symptoms reported during this study showed the incidence of acute mountain sickness occurred in 10% of the participants at a simulated 3000 meters, increasing to 90% at 4050 meters. As mentioned, the average heart rate increases and oxygen saturation decreases as the elevation increases. The baseline heart rate at sea level was 62 beats per minute, increasing to 80 at 3000 meters and 93 at 4050 meters. Ideally health care providers aim to oxygenate vital organs by keeping the oxygen saturation level between 92-100%. The lower the oxygen level the harder it is to keep organs properly profused. Age, health status, and place of residence are taken into consideration when examining study reports. Oxygen saturation at sea level was 98% decreasing to 92% at 3000 meters and 84% at 4050 meters.
As mentioned in a previous post by Dr. Neale Lange, sleeping at high altitudes can be hard due to the frequent awakenings and nocturnal hypoxia caused by the low oxygen levels at higher elevation. This study reiterates these findings with the results of the average oxygen saturation at 3000 meters being around 92%. Dr. Lange also found that sleep apnea was often more prominent and had more negative effects on the human body in environments that were lower in oxygen. This study agrees with that statement finding that people with sleep apnea had twice the hourly awakenings compared to those at higher elevation that did not have sleep apnea. Dr. Lange also pointed out that the contribution of hypobaric atmosphere to symptoms at altitude as opposed to pure hypoxemia is unknown. Frisco, Colorado is at an elevation of 2800 meters. Ongoing research at Ebert Family Clinic including residents and visitors along with laboratory studies such as this one can guide decisions about interventions and treatment to improve sleep and help us enjoy our time in the mountains.
References
Figueiredo PS, Sils IV, Staab JE, Fulco CS, Muza SR, Beidleman BA. Acute mountain sickness and sleep disturbances differentially influence cognition and mood during rapid ascent to 3000 and 4050 m. Physiological Reports. 2022;10(3). doi:10.14814/phy2.15175
Blog post: HOW DO YOU DEFINE A GOOD NIGHT’S SLEEP?:AN INTRODUCTION TO THE SLEEPIMAGE RING, AN INTERVIEW WITH DR. NEALE LANGE
Casey Weibel is a 2nd year student at Drexel University, born and raised in Pittsburgh, Pennsylvania. He went to Gannon University for his undergrad and got a degree in biology. Before PA school, Casey was an EMT. He enjoys hiking and kayaking and is a big sports fan.
Wild animals, storms, avalanches, cold, high altitude pulmonary edema or cerebral edema, falls, fires and injuries are the most common dangers in the mountains. I’ve climbed 19 different mountains in Colorado over 14,000′, and some of them more than once, making for 28 successful ascents. But I called Summit County Search and Rescue Saturday for something I was not expecting: deep wet snow that trapped me less than 2 miles from the trailhead.
Summit County trail map
It was a bright, warm day — I had even left my hand warmers at home. My plan was to hike from Miners Creek trailhead in Frisco to Gold Hill Trailhead north of Breckenridge which is about a 6- or 7-mile trip one way. I had hiked from both ends in previous weeks and saw the turn-off had snow and no tracks. I attached my snowshoes to my backpack with plans to turn up towards Gold Hill if there were tracks, and there were.
After 4 miles I was out of the forest on top with gorgeous 360˚ views of mountains. I no longer saw the trail markers or tracks so set out across the open space with my snowshoes sinking into the snow every 10 to 20 feet. The trail maps and GPS on my phone were sketchy, only showing I was very near the Colorado Trail. I turned down a logging road to get out of the wind thinking the snow would be packed. I could see several open areas that I thought would take me to the familiar trails to Gold Hill.
After an hour sinking into deep snow I noticed I had only one snowshoe. I backtracked 100 feet following the tracks to find it, dug at several spots where I had sunk the deepest but never found it. I went back towards the Colorado Trail but could not progress, having to dig my boot out of deep snow several times. I tried to backtrack in my footsteps but couldn’t get far. I had now covered a mile in an hour and a half, my phone showing I was only 48 minutes from the Gold Hill trailhead.
So I called 911, thinking they could drive a snowmobile up to get me. Bad news: the vehicle would just sink the same way I was. The 911 operator knew me and the Summit County Search & Rescue mission coordinator Mark Svenson was in touch several times as I waited from 3:17 until about 6 pm when the crew arrived with skis and extra snowshoes. My Blue Heeler Isa and I stayed within one foot of a small pine tree where we found firm footing after rolling through the deep, soft snow. Luckily the sun kept us warm until 5 pm, and I had food and water. My gloves and boots were soaked so my feet were very cold and I tried to keep Isa lying over my legs or feet. I had a plastic rain shield extension that I could pull out and sit on in a pocket of the backpack that one of my students had gifted me.
The rescuers had water, snacks, dry socks, dry gloves, gators and snowshoes. They had packed down the trail but there were still times we post-holed on the way down. We arrived at the rescue vehicle as darkness fell. Special Operations Sheriff SJ Hamit waited with Mark and other SCSR staff to welcome us. One of the rescuers told me how happy he was that I was still smiling when they arrived!
Summit County Search & Rescue team, Sheriff Hamit on the left, Dr. Chris far right.
What did I learn? Stay out of deep, wet snow even if it means going back the long way. Bring extra socks and gloves. Buy gators.
I was not afraid because I knew they were coming before dark. I do feel exhilarated that I was able to do such a challenging hike without any pain or blisters, that my knees were strong enough to extract my feet from the deep snow so many times, and that Isa was with me to warn if any animals were near and announce when the rescuers arrived.
Christine Ebert-Santos, MD, MPS is the founding physician and president of Ebert Family Clinic in Frisco, Colorado, where she leads high altitude research in addition to running a full-time family practice. Isa is a two-year-old blue heeler and Dr. Chris’s familiar and guardian angel.
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?
Individuals with symptoms after 2 weeks of a positive COVID-19 test without hospitalization,
Individuals with symptoms after 2 weeks after hospital discharge,
Anyone who required care in the intensive care unit (ICU), and
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:
Individuals who have symptoms after 2 weeks of a positive COVID-19 test without hospitalization
Individuals who have symptoms after 2 weeks after hospital discharge
Any patient who required care in the intensive care unit (ICU)
Any patient who developed myocarditis or thromboembolic events
General recommendations for anyone before high-altitude travel:
Monitor pulse oximetry after arrival of high altitude, and access care or descend if symptoms worsen.
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.
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)
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:
Severely elevated pulmonary artery pressures may be a reason to forego high-altitude travel altogether.
High-altitude travel should likely be avoided while active inflammation is present in myocarditis.
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:
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
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.
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.
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.
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.
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.
