Category Archives: Backcountry

Return to High Altitude after Recovery from Coronavirus Disease 2019

Andrew M. Luks and Colin K. Grissom

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

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

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

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

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

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

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

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

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

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

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

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

Quick Summary of Recommendations

Individuals who require evaluation prior to high-altitude travel:

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

General recommendations for anyone before high-altitude travel:

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

Reasons to forgo high-altitude travel:

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

References:

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

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

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

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

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

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

Effects of High Altitude on Diabetes Management:

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

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

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

Pre-trip Prep:

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

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

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

Table 1: Environmental Effects on Diabetes, Imported from WMS

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

Table 2: Medical Kit Preparation, Imported from WMS

Treatment of ketoacidosis or HHS:

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

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

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

Conclusion:

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

(All tables and figures imported from WMS)

References:

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

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

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

High Country Winter Dogs

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.

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

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

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

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

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

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

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

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

What conditions do you see commonly here at altitude?

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

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

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

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

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

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

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

Are cataracts a more common condition at altitude?

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

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

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

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

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

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

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

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

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

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

Dr. Cook performing an eye exam on me.

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

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

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

Paraguay Takes On Colorado’s Fourteeners

After a horrendous Autumn of forest fires in Colorado, we’ve received well over a foot of snow in a series of storms, and it’s safe to say Winter has arrived. Hiking season is never truly over in the Rockies, but Colorado’s famed Fourteeners are now blanketed in snow, increasing the risk of any attempted ascent exponentially. But through the fire and ice, the Summer yielded ample opportunity for at least one enthusiast to check off more of her bucket list adventures.

Since leaving her home in Paraguay, mountaineer and hiking expert Clarissa Acevedo Santos has spent over a decade ascending Colorado and Hawai’i’s highest peaks. In addition to her excursions in the Ko’olau and Kahalawai ranges including Maui’s Haleakalā crater, she has summited well over half the 58 peaks in Colorado over 14,000 feet, making her the first from her country of record to do so.

She was invited on her first Fourteener years ago when friends took her up Quandary outside of Breckenridge, CO, at 14,271′ (4350 m).

“When I hiked that first mountain, it was hard, because I wasn’t used to gaining that much elevation. I didn’t really enjoy it so much because of how cold it was on the summit. Even though I made it to the top, I wasn’t really having fun with not feeling my lips and not feeling my fingers because it was really, really cold. I could barely smile, and we couldn’t even enjoy the summit because of how windy it was!

“After that hike, I didn’t hike for a while, and I got invited again to climb Mt. Elbert in 2012. It was actually much more enjoyable because it was with a big group of college kids from Summit and the weather was just perfect. We were able to summit it and enjoy the day and have lunch up there. So that’s what started to change my mind about hiking Fourteeners because I enjoyed my time up top. That’s when I realized it’s not always difficult to be up there. I think I got what all the hikers call ‘Peak Fever’. So after that is when I feel like I started going non-stop, and I met more friends that were into hiking, and researched more about the mountain before I go.

“I always go with people who knew more about it, so I started learning more with other friends and other hikers. And I started feeling actually great when I got higher. It was always harder to get started close to the beginning [of the trail], just to gain all that elevation. But then when I was getting close to the summit, I just got more energy. I just got more excited to be at the top. That’s the goal. It’s a great feeling.”

Clarissa has an app that she uses to record all her summits called Colorado 14ers that allows her to keep record of and upload photos from every Fourteener she’s hiked. She pulls it up as she recounts year after year of more and more summits, some she’s even done more than once.

There is a class system rating every trail by level of difficulty, Class 1 being the easiest and Class 4 being the most difficult. The most difficult peak Clarissa recounts climbing is Long’s Peak, as well as the most dangerous weather she’s climbed in.

“It was a little bit late to summit it. It was not a good idea. If the rocks got wet, it could be very dangerous. There were people turning around. We decided to wait on a ridge. There were three [of us], and one turned around. He wasn’t feeling good, he was getting tired, he wasn’t used to hiking that many hours.

“We decided to wait for the clouds to go away. After that we just kept going. It did not rain on us, thankfully.”

Clarissa has seen her share of altitude sickness as well. One of her frequent hiking companions repeatedly gets stomachaches and headaches everytime they hike, in spite of being an experienced hiker as well.

“I always ask [one of my friends in particular] if she wants to stop or if she wants something. She normally doesn’t eat before she starts a hike. No breakfast. But I also carry ginger candy … I learned that from other hikers telling me it can help settle your stomach a little bit. It’s everywhere, in all the stores. Now they’ve created gums. I’ve started chewing them on my hikes just in case. You never know. I’ve seen people who hike all the time, and they ate something that didn’t digest well, and they feel sick and get a little dizzy.

“I’ve never experienced any headaches on the way up. The only time I remember having a headache is when I ran out of water. I hiked Oxford and Belford in the Saguache range in the same day. My head hurt and it lasted for that night. Now I take a filter with me so I can fill my [Camelbak] bladder. And I also take electrolytes. And I’ve started hiking with poles more as well, just because you put alot of weight on your knees when you’re hiking down. It’s very smart to start using poles.”

When it comes to preparing such demanding ascents, Clarissa recommends spending some time at an intermediate altitude before hitting the trail, and staying well-hydrated. Caffeine and alcohol the night before doesn’t typically help.

Clarissa with her husband on their way up Mt. Shavano in September 2019.

“It doesn’t matter how fit you are … you can still get really sick. I’ve heard of people who get headaches for several days because [they’re] not used to [the elevation here].”

She also says it’s important that you start any hiking at all to build the strength in your lungs.

“It does hurt,” she says about the stress on your respiratory system. “I remember when I was hiking Quandary, my chest was so pressed, my heart was [beating] so fast, my stomach was feeling weird, like I had to pee or I had to do number two or something. It was such a difficult part of … gaining all that elevation.”

“You’ve gotta find a good pace for yourself. I see many of my friends going really fast ahead of me, then they’re very tired and they have a hard time getting to the top. I’ve waited for many people because they are struggling so much at the end. Take as many breaks as you think [you need]. Carry enough water!

Clarissa keeps seeing a lot of hikers running out of water. “They just bring a tiny plastic bottle. That’s a huge mistake. And bring food, too. You will get hungry after a mountain. It’s so funny how many people are unprepared. If I’m hiking with newbies, I make sure they have everything, and they’re always thankful.”

When it comes to clothes and shoes, Clarissa recommends really good traction. She’s tried some more affordable brands, but says the durability is worth paying more for.

Don’t ever hike in new hiking shoes before you’ve broken them in. Good hiking socks also have more padding at the heels and toes and help prevent blisters. She also will double-up on socks, or even bring an extra pair to help mitigate possible cold.

“I reapply sunscreen on my hikes two to three times. Many times my nose will burn. I always carry sunglasses. You’re so close to the sun, you don’t realize. You don’t want to burn your eyes or your face. Even with the sunglasses, having a hat on top of it doesn’t hurt. Even in the Summer in the mountains, carry additional gloves or layers, because you don’t know what the weather could be. Temperature changes quick.

“I just recently purchased a nice puffy Northface that helped me. I will always have a thin layer underneath because you get hot and cold. You’re gaining elevation, you get hot, then you get cold in the middle …”

When it comes to navigation, Clarissa’s main resource is 14ers.com, which allows you to download offline maps, so you aren’t relying completely on having cell service.

“Even though I have hiked many of them, I want to be sure I’m going the right direction … I just love reading everything I can beforehand. I read about the class, how much exposure, how long it’s going to take, then I download the maps, look at the maps, what kind of road it’s going to be, if my car can make it up higher or if I have to hike longer.”

Clarissa has heard of other Paraguayans hiking around the world, but has never met another one on a Fourteener personally. But she does meet a lot of people from around the world on these ascents who ask if there are mountains in Paraguay. The highest is Cerro Peró at 2762′ (842 m) in this landlocked country known more for its rivers and the hydroelectricity they provide for Paraguay and its neighboring countries, including Brazil and Argentina.

Clarissa says she’s learning more and more each year about mountaineering and advocates learning as much as possible about each ascent before you go. The weather may be different every single time.

Bring the layers, whether you think you’ll need them or not. And leave no trace.

Thank you, Clarissa, for sharing your continuing legacy, and be safe up there!

robert-ebert-santos
Powder ‘stache.

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not developing applications and graphics, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery. Clarissa is his wife who is increasingly a much faster, more experienced mountaineer than he is, but he will occasionally feel ambitious enough to join her on a Fourteener, at the top of which they both enjoy a delicious cider, weather permitting.

Acetazolamide

Typical symptoms of acute mountain sickness (AMS) are headache, loss of appetite, disturbed sleep, nausea, vomiting, fatigue, and dizziness. However, more serious conditions such as high altitude pulmonary edema (HAPE) or cerebral edema (HACE) can present with this illness. Avoiding these unpleasant symptoms while at elevatione is possible through gradual pre-acclimatization when possible (what science recommends!), or there are specific medications that can potentially prevent the development of AMS, such as acetazolamide. This article will address how acetazolamide (also known as Diamox) can help prevent AMS, discuss the physiological effects of the medication, some side effects, and whether or not this drug can enhance physical performance.

 How does it work?

Acetazolamide is a carbonic anhydrase inhibitor. Carbonic anhydrase regulates kidney absorption of sodium bicarb and chloride. Acetazolamide works by inhibiting carbonic anhydrase, preventing the reabsorption of sodium bicarb and chloride, causing acidosis in the blood. When experiencing AMS, the body is in a state of respiratory alkalosis. By taking acetazolamide, which causes metabolic acidosis it drives receptors in the body to increase the patient’s minute ventilation by as much as 50%, improving arterial PO2 and increasing oxygen saturation.

How can I obtain acetazolamide and when should I start taking it?

Acetazolamide requires a doctor’s prescription, and the typical dose for the prevention of AMS is 125 mg twice daily. The typical recommendation is to start taking acetazolamide one day before your exposure to high altitude and continue usage throughout your trip. When taken one day before exposure, studies show that acetazolamide reduced AMS incidence and enhanced tolerance to submaximal exercise on the first day at high altitude versus starting administration the day of arrival.2 However, if, for some reason, the medication isn’t started a day before arrival to high altitude, then the medication should be started upon arrival, which still shows a decreased incidence in the development of AMS. 

Allergies & Side Effects

Acetazolamide belongs to a classification of drugs known as sulfonamides, which is broken down further into two categories: antibiotics and nonantibiotics. Acetazolamide is considered a nonantibiotic sulfonamide, which varies significantly from sulfonamide antibiotics because these antibiotics contain what is known as an arylamine group in their chemical structure. This arylamine group is a key component of the allergic response to sulfonamide antibiotics (sulfamethoxazole, sulfasalazine, sulfadiazine, and the anti-retrovirals amprenavir and fosamprenavir); however, this structure is not present in other sulfonamide drugs like acetazolamide.1 There is available evidence that suggests patients who are allergic to arylamine sulfonamides do not cross-react to sulfonamides that lack the arylamine group and so may safely take non-arylamine sulfonamides.1 Patients with known allergies to sulfonamide drugs should consult with their healthcare provider before taking acetazolamide.

Like all other medications, there are risks that side effects will occur with acetazolamide’s administration. The common side effects are fatigue, malaise, changes in taste, paresthesia, diarrhea, electrolyte disorders, polyuria, and tinnitus. While conducting research, I found 3 – 4 people from my hometown, located at 69 feet above sea level, who have taken acetazolamide while rapidly ascending to 8,000+ feet to ski or hunt. When asked how their experience was taking acetazolamide, the common response was that they stopped using it within the first two days due to the change in the taste of their beer! The pleasurable “fizz” in our carbonated drinks is attributed to chemical excitation of nociceptors in the oral cavity via the conversion of CO2 to the carbonic acid in a reaction catalyzed by carbonic anhydrase. So administering a carbonic anhydrase inhibitor like acetazolamide results in flat-tasting carbonated drinks, or, as described by the aforementioned subjects, a “nasty beer”!4 While a bad tasting beer is no fun, AMS is a lot less fun, and one would be best advised to continue taking acetazolamide while at high altitude.

Can taking acetazolamide increase physical performance and endurance at high altitudes?

Though enticing, it doesn’t seem to work out that way. There are multiple studies on exercise endurance in hypoxic conditions with the administration of acetazolamide, but the produced results are confounding. The majority of the studies show that for a non-acclimated person taking acetazolamide in hypoxic conditions, endurance and exhaustion time were increased with submaximal and maximal exercise. A few reasons this may be true are the induction of metabolic acidosis and its effects on muscle cells, the diuretic effect of the drug inducing dehydration, and additional increases in work of breathing cause vasoconstriction in locomotor muscles, which can impair exercise performance.3 Regardless, this medication’s proven science in the prevention of AMS should not be mistaken with the multiple confounding studies on exercise endurance.

Scott “Scotty B” Rogers, FNP-S

From Opelousas, Louisiana, Scott Rogers is currently a Family Nurse Practitioner student at Walden University after having practiced five years as an RN following his BSN from the University of Louisiana at Lafayette. He has lived in Colorado for the past four years where he enjoys hiking with his wife and dog, snowboarding all the resorts in Summit County, and basketball, and hopes to pursue more work with acute physical rehabilitation, orthopedics, and sports medicine.

References

1. American Academy of Allergy Asthma & Immunology. (2019, June 23). Acetazolamide and sulfonamide allergy: AAAAI. Retrieved November 13, 2020, from https://www.aaaai.org/ask-the-expert/acetazolamide

2. Burtscher, M., Gatterer, H., Faulhaber, M., & Burtscher, J. (2014). Acetazolamide pre-treatment before ascending to high altitudes: when to start?. International journal of clinical and experimental medicine, 7(11), 4378–4383.

3. Garske, L., Medicine, 1., Brown, M., Morrison, S., Y, B., G., B., . . . Zoll, J. (2003, March 01). Acetazolamide reduces exercise capacity and increases leg fatigue under hypoxic conditions. Retrieved November 13, 2020, from https://journals.physiology.org/doi/full/10.1152/japplphysiol.00746.2001

4. Jean-Marc Dessirier, Christopher T. Simons, Mirela Iodi Carstens, Michael O’Mahony, E. Carstens, Psychophysical and Neurobiological Evidence that the Oral Sensation Elicited by Carbonated Water is of Chemogenic Origin, Chemical Senses, Volume 25, Issue 3, June 2000, Pages 277–284, https://doi.org/10.1093/chemse/25.3.277

WMS Blog Entry No. 5: Advances in Frostbite, a Synopsis of Dr. Peter Hackett’s Lecture

Frostbite is an injury caused by freezing of the skin and underlying tissue. The main pathophysiology of frostbite is ischemia. Basically, where there is blood flow there is heat and where there is no blood flow there is no heat to that area. The vasoconstriction and loss of blood flow to the skin predispose the skin to becoming frozen. Heat transfer depends on blood flow and blood flow depends on sympathetic nerve tone. In our extremities, there are only nerves that cause vasoconstriction. Exposure to cold or a drop in the body’s core temperature can induce vasoconstriction from these sympathetic nerves in which decreases the amount of blood flow to the extremities to keep the central aspect of the body warm and central organs well-perfused to help to maintain the body’s core temperature.

Frostbite usually occurs in the apical areas of the skin also called glabrous, which is Latin for smooth because these areas have no hair. These areas include the face, palmar surface of the hand, and the plantar surface of the foot. These areas of the skin are rich in arteriovenous anastomoses, which are low-resistance connections between the small arteries and small veins that supply the peripheral blood flow in the apical regions of the skin. These anastomoses allow the blood to flow into the venous plexus of the skin without passing through capillaries, and play a major role in temperature regulation.

Causative factors of frostbite include inadequate insulation, circulatory compromise, dehydration, moisture, trauma, and immobility. All of these factors in combination can result in frostbite.

The behavioral risk factors include mental illness, alcohol/drug use, fear, apathy, and anxiety. All of these risk factors can contribute to frostbite, generally, from poor self-care.

Frostbite is said to kill twice during its two phases that occur. The first phase is the frozen phase in which ice crystals form in the intracellular compartment at about 29 degrees Fahrenheit. These ice crystals will suck the fluid out of the endothelial cells and become enlarged causing the endothelial cells to lyse from dehydration and interrupt microcirculation. The second phase is the rewarming phase in which the skin thaws and is at risk for microthrombi production and necrosis due to prolonged injury to those endothelial cells.

The usual phase at which we see frostbite in a clinical setting is after thawing, in which the skin looks flushed pink, red, with the appearance of blebs that form one hour to twenty-four hours after thawing. These blebs can rupture spontaneously in 4-10 days and shortly after, a cast-like eschar forms. Then the eschar usually sheds in 21-30 days.

Deep Frostbite

Frostbite is classified based on the depth of tissue damage, from superficial with no tissue damage being mild and deep tissue damage including muscle, bone, or tendon being classified as severe frostbite. The mildest form of frostbite is called frostnip. Frostnip is freezing of the skin but there is no actual freezing injury and doesn’t cause permanent skin damage.

Stages of Frostbite

What can you do in the field for Frostbite?

It is important to provide supportive care with IV or PO hydration to prevent dehydration. If the affected area is frozen with no imminent rescue, it is recommended to thaw the area with warm water and try to avoid refreezing. You can give NSAIDs, such as Ibuprofen, 400 mg every 8 hours, or ketorolac 30 mg IV. If the person is at altitude and their oxygen saturation is low you can provide oxygen. However, the individual must be taken to the nearest hospital for further treatment, especially in cases of severe frostbite.

New research studies have been exploring the use of thrombolytics in the treatment of frostbite. Many of the research studies have shown that IV TPA or iloprost may be of benefit to administer in a hospital setting. However, iloprost is not approved for IV use in the United States and other prostacyclins have not been studied for the use of frostbite as of yet. There are current literature and guidelines that have been published for the prevention and treatment of frostbite, however, more research is needed to further support standardized treatment of all patients with frostbite with thrombolytic therapy. Hopefully, these new studies will encourage more research into using thrombolytics and prostacyclins for frostbite.

In the meantime, it would be best to stay warm to prevent frostbite. Tips to help in frostbite prevention include:

  • Limit time you’re outdoors in cold, wet, or windy weather. Pay attention to weather forecasts and wind chill readings. In very cold, windy weather, exposed skin can develop frostbite in a matter of minutes.
  • Dress in several layers of loose, warm clothing. Air trapped between the layers of clothing acts as insulation against the cold. Wear windproof and waterproof outer garments to protect against wind, snow, and rain. Choose undergarments that wick moisture away from your skin. Change out of wet clothing — particularly gloves, hats, and socks — as soon as possible.
  • Wear a hat or headband that fully covers your ears. Heavy woolen or windproof materials make the best headwear for cold protection.
  • Wear socks and sock liners that fit well, provide insulation, and avoid moisture. You might also try hand and foot warmers. Be sure the foot warmers don’t make your boots too tight, restricting blood flow.
  • Watch for signs of frostbite. Early signs of frostbite include red or pale skin, prickling, and numbness.
  • Eat well-balanced meals and stay hydrated. Doing this even before you go out in the cold will help you stay warm.

Lauren Pincomb Apodaca is a second-year Physician Assistant student in the Red Rocks Community College Physician Assistant Program. Originally from Las Cruces, New Mexico, she graduated from New Mexico State University with a Bachelor of Science in Biochemistry and a Bachelor of Art in Chemistry. After obtaining her undergraduate degrees, she was accepted as a Ph.D. fellow in Pharmacology at the University of Minnesota where she conducted research in a biomedical laboratory doing cancer research. She then realized that she wanted to make a difference in people’s lives through hands-on experience rather than working in a laboratory. She went back to New Mexico and received her certification as a nursing assistant and started from the ground up to reach her ultimate goal of being a Physician Assistant. She has enjoyed living in Colorado and the many outdoor activities that Colorado has to offer. Her favorite are kayaking, fishing, and hiking. She is looking forward to graduating soon.

References:

Hill, C. (2017, December 22). Cutaneous Circulation – Arteriovenous Anastomoses. Retrieved September 27, 2020, from https://teachmephysiology.com/cardiovascular-system/special-circulations/cutaneous-circulation/

Frostbite. (2019, March 20). Retrieved September 27, 2020, from https://www.mayoclinic.org/diseases-conditions/frostbite/symptoms-causes/syc-20372656

WMS Blog Entry No. 4, Part I: Tick Bite Prevention and Proper Removal

Ticks are blood feeding parasites. Ticks are known as vectors because they can transmit different pathogens responsible for several diseases including Colorado Tick Fever, Rocky Mountain Spotted Fever (RMSF), Tularemia and relapsing fever. While there are 27 species of ticks in Colorado, almost all human encounters w/ ticks in Colorado involve the Rocky Mountain wood tick, a tick that only lives in the western U.S. and southern Canada at elevations between 4,000 and 10,000 feet. Another highly prevalent tick is the brown dog tick which is specific to dogs.

Before you go out!

DO:

  • Wear protective clothing! Wearing long sleeved shirts, long pants tucked into your socks and close toed shoes can keep ticks from getting onto your skin, as ticks are usually acquired while brushing against low vegetation.
    • wear light colored clothing, as this makes it easier to find ticks that have been picked up
    • Treat clothing w/ permethrin as this can help kill or repel ticks for days to weeks! Do not apply directly to skin.
  • Use Tick repellent. This includes the well-known DEET along with picaridin, IR3535 and oil of lemon eucalyptus
    • Repellent can be applied either directly to skin or to clothing, AND is most effective if applied to the lower body that is likely to come in contact with ticks first!
    • If applying repellents to skin:
      • DO NOT use high concentration formulas on children (DEET concentration > 30)
      • AVOID applying repellents to your hands or other areas that may come in contact with your mouth
      • DO NOT put repellent on wounds
      • ALWAYS wash skin that has had repellent on it.
  • Remember: Dogs can get ticks too! Don’t forget to consult your veterinarian about how to protect your furry friends against ticks.

When you go out: DO NOT assume that you won’t get bit.

  • Avoid tick habitat
    • Ticks are most active in spring and early summer and are concentrated where animal hosts most commonly travel, including areas of brush along field and woodland edges or commonly traveled animal host paths though grassy areas.
      • DO try to avoid exposure in these areas by staying in the center of marked trails when hiking to avoid brushing vegetation that ticks may be perched on waiting for you!
    • If possible, avoid these sites during tick season.
    • If you live in known tick territory, you may even get a tick bite in your own backyard! Decrease this risk by creating a tick-free zone around your house by keeping your lawn mowed, eliminating rodent habitats (wood or rock piles) around your house, and placing wood chips between your lawn and tall grasses or woods.

After coming back inside

  • Perform a tick check which includes botha visual and physical inspection of your entire body, as well as your gear and pets. Because ticks take several hours to settle and begin feeding, you have time to detect and remove them. You tend to not feel ticks because their saliva has histamine suppression and analgesic effects. Ticks like warm, moist and dark areas but can latch anywhere.
    • Examine your scalp, ears, underarms, in and around the belly button, around the waist, groin/pubic area, buttocks and behind your knees.
    • If camping, perform tick checks daily on humans AND pets, making sure to examine children at least twice daily. Again, pay special attention to the head and neck and don’t forget to check clothing for crawling ticks.
    • Shower and wash your clothes after returning home from the outdoors.

If you or a family member get bit by a tick: DO NOT PANIC, and DO NOT immediately rush to the emergency room! If the tick has been attached for less than a day, the chance of the tick transmitting one of these diseases is low. Removing ticks can be tricky, as they use their mouthparts to firmly attach to the skin.

Best method for tick removal -> remove as quickly as possible!

1. Grasp the tick with fine tipped tweezers as close to the skin as possible. If tweezers are not available, use a rubber gloved hand or place tissue or thin plastic over the tick before removing it to avoid possible transmission of disease.

2. Pull tick SLOWLY and with STEADY PRESSURE STRAIGHT away from the skin

  • DO NOT:
    • Crush, puncture, twist or jerk the tick as you remove it. This may increase risk of the tick regurgitating infected body fluids into the skin or leaving mouthparts in skin

3. After the tick is removed, disinfectant the attachment site on skin and WASH YOUR HANDS. Dispose of the live tick by placing in a sealed bag/container and submersing it in alcohol, then wrapping it tightly and crushing it in duct tape, OR flushing it down the toilet.

  • DO NOT:
    • crush the tick in your fingers
    • try to suffocate the tick still on the person by covering it with petroleum jelly OR touching it with a hot match to suffocate -> these methods can cause the tick to burst and INCREASE time the tick is attached, as well as making the tick more difficult to grasp

Remember: the goal is to remove the tick quickly from the host as opposed to waiting for it to detach on its own.

If you remove the tick and are worried, you can always put the tick in a sealed container with alcohol and bring the dead tick to your medical provider.

If you develop a rash or flu-like symptoms (fever, fatigue, body aches, headache) within several weeks of removing tick, see your medical provider and tell him/her about the recent tick bite, when it occurred and where you acquired the tick.

Remember: These diseases are very treatable if caught early enough!

Graphic taken from https://www.cdc.gov/ticks/pdfs/FS_TickBite-508.pdf

Stay tuned for next month’s explanation of the tick life cycle and tick-borne diseases in the high country!

References

1. Colorado Tick and Tick Born Diseases fact sheet. https://extension.colostate.edu/topic-areas/insects/colorado-ticks-and-tick-borne-diseases-5-593/ Accessed on 8/8/20

2. Peterson J., Robinson Howe. P. Lyme Disease: An Uptick in Cases for 2017. Wilderness Medicine Magazine: https://www.wms.org/magazine/1213/Lyme-Disease. Accessed 8/8/20

3. Do’s and Don’t’s of Tick Time: https://awls.org/wilderness-medicine-case-studies/dos-and-donts-of-tick-time/ Accessed 8/8/20

Laurie Pinkerton is a 3rd year Physician Assistant Student studying at Drexel University in Philadelphia, PA. Originally from Northern, VA, she graduated from the University of Mary Washington in Fredericksburg, VA with a degree in Biology in 2014. She moved to Keystone to live that ski life and stayed for 2 years, working as a pharmacy tech at Prescription Alternatives and as a medical assistant at Summit Cardiology. Prior to starting PA school, she moved to Idaho where she learned about organic farming and alternative medicine.  She has loved every second of being back in Summit County and learning here at Ebert Family Practice. She looks forward to practicing Integrative Medicine in the near future.

WMS Blog Entry No. 3: Pre-acclimatization, A Synopsis of Dr. Peter Hackett’s Lecture

What is pre-acclimatization? It is a process of adjusting to a new climate, usually higher elevation, reducing hypoxemia in high altitude settings in turn saving time, money, and most importantly, reducing altitude sickness. It can also allow for better sleep/comfort and physiological/cognitive performance at a high altitude. Acclimatization is a time-dependent process as over 5,000 genes are impacted by a large shift in elevation affecting ventilation, plasma volume, and hemoglobin mass, among other things. The whole process is not completely understood, but one key element is the hypoxic ventilatory response (HVR). HVR is activated by the aortic artery baroreceptors, as oxygen in the blood reduces it triggers an increase in respiration. This happens immediately as you ascend in altitude and maximizes at 7-14 days. Arterial oxygen increases by an increase in ventilation/saturation and also by dropping plasma volume, increasing hemoglobin concentration, and then later on, increasing overall Hgb production which in theory, overall decreases altitude sickness.

So how can you prepare yourself or pre-acclimatize?

Some of the better-known methods are spending time at higher altitudes prior to your destination, using a hyperbaric or normobaric chamber, blood doping, hypoxic exercise training, and a few pharmaceutical methods. All of these are options, but the key question is, which ones truly work?

Pre-acclimatization with actual altitude is the most useful. Generally speaking, you would pick your maximum sleeping altitude at your destination and slowly work your way towards that altitude. You pick an ascent profile which preferably would be spread over a week or more to be most useful. This pre-acclimatization should be completed no more than 1-2 weeks prior to your destination so that any pre-acclimatization gained doesn’t wane prior to your trip.

Simulated altitude is another option which includes hypoxic tents, hypoxic rooms/homes, hypoxic exercise chambers, and hypoxic masks. Out of these four, hypoxic tents or hypoxic rooms/homes, where exposure is over a long duration, are by far the most effective. Hypoxic masks and exercise chambers are not very effective as their short duration does not give the body enough time to make the proper adjustments and although might be beneficial in respiratory muscle training/performance, do little in the way of pre-acclimatizing your body. Studies show more benefit from hypobaric hypoxia training vs normobaric hypoxia training but keep in mind studies are very limited and warrant much further research. Overall, simulated altitude minimum requirements look to be somewhere in the range of 1 week of exposure, 7 hours per day, and a minimum effective altitude of 2200-2500 m and being no more than 1500-2000 m below your target sleeping altitude. Shorter term protocols can attenuate altitude sickness but not the incidence some studies suggest. As to why hypobaric methods are more effective than normobaric methods, no one really knows yet and more research is needed.

Changing your living destination to something at a much higher elevation and exposure over years or moderate altitude residence (MAR), is the most effective method according to some studies, but this is far from feasible for most. There are studies to show epigenetic changes for those who relocate to higher elevations for long periods and these appear to be much less than those who have genetically adapted to higher elevation over generations but still more effective than the previous mentioned short-term options.

Hikers often camp at the Angel of Shavano campground before ascending Mt. Shavano, one of Colorado’s famed fourteeners.

Oxygen saturation is maximal at 11 days of exposure to a specific elevation. Diamox (acetazolamide) increases ventilation and can help with acclimatization but there isn’t much data on how using this pharmaceutical compares to other methods mentioned. World-renowned high altitude expert and pioneerDr. Peter Hackett theorizes that it may fall just short of MAR, but again, more research is needed. Short-term altitude exposure shows benefits at 7 days but a longer exposure such as 15 days has been shown to be much more beneficial.

Blood doping with EPO can be somewhat effective over a 4+ week treatment and can potentially decrease AMS and potentially increase exercise performance but the data is limited and conflicting on this. Also, it appears that it is only effective up to 4,300 m but not beyond that as arterial oxygen content is not the determining factor for sleep and cognition performance at high altitudes but rather oxygen delivery which is affected by hematocrit and viscosity of blood.

Hypoxia inducible factor (HIF) is a regulatory factor in cells that respond to a reduction in oxygen, causing changes in about 5000 different genes to help the body adjust to meet oxygen requirements. It is suggested that we could pharmaceutically activate this factor prior to destination in order to acclimatize the patient allowing for less complications and better results at higher elevations. Currently there are some drugs in trials but nothing specifically FDA approved.

Overall, data and studies are limited but the most effective current pre-acclimatization method is long-term altitude training (real or simulated). If possible, plan your ascent trip to be slow and steady to obtain best results with the least amount of complication.

Joel Miller is currently preparing to graduate from Red Rocks Community College’s reputable Physician Assistant program this Fall. He has been a resident of Colorado for four years where he has immensely enjoyed the outdoors camping, fishing, hiking, hunting, and exploring Colorado’s wide variety of breweries.

WMS Blog Entry No. 2: Long Distance Backpacking, the Wisdom of Dr. Sue Spano

Graduate of Temple University School of Medicine, Director of Wilderness Medicine Fellowship at University of California San Francisco Fresno Department of Emergency Medicine, Sue Spano, MD, FACEP, FAWM presented twice this year at the Wilderness Medicine Society’s annual (virtual) conference. Boasting the experience of about a thousand miles of the Pacific Coast Trail in Oregon and California and other recreational excursions, she shared a wealth of advice and personal recommendations for long distance backpacking.

To put it all into perspective, she referenced the Pacific Coast Trail (PCT), John Muir Trail (JMT) and the Appalachian Trail, each covering 2650 mi, 211 mi, and 2200 mi respectively. These are trips that last, easily, months. The general time frame for many of her recommendations is about five to six months.

Not surprisingly, the issue of weight comes up frequently for travelers. There are a number of studies done on this, from body mass index to base pack weight, and every ounce counts. While fitness level does not directly correlate to the incidence of injury, increase in BMI does correlate directly to increased risk of illness, injury, and trail evacuation. It is notable, however, that in a poll, about 2/3 of those hiking the PCT and well above those on the JMT trained before embarking on the trail, and most of them considered themselves to be “above average” in their level of fitness (7 or 8 on a scale of 1 to 10).

Although Dr. Spano does recommend carrying backups of three things — lighters, water treatment systems, and first aid — when it comes to base weight, there are several items that may be worth a little more investment for fewer ounces. Right off the bat: trail runners over boots. The mere difference in ounces becomes significant after so many miles, and the flexibility of softer shoes helps prevent a lot of discomfort (blisters, for example). She also notes that trail runners are more breathable and dry more quickly, sharing that she doesn’t typically bother to take them off to cross water or in snow as they will dry right on your feet along with your socks. It would be interesting to hear accounts of the footwear of preference on the Colorado Trail, where elevations are frequently higher and there may likely be more snow in general.

In another poll, 21.8 lbs was the base weight carried by packers, most of whom would have carried less in hindsight. This can be achieved by investing in lighter backpacks, tents, hiking poles, sleeping bags and sleeping pads, specifically. ULA Equipment out of Logan Utah makes an ultra-light pack that Dr. Spano prefers, “no conflict of interest”, just her personal favorite.

Skip the toothpaste, Spano urges. It doesn’t actually clean your teeth, so you might as well just brush with water.

Something else we’re seeing more and more of on distance excursions is tents that incorporate hiking poles as tent poles. Hiking poles themselves are recommended more and more as well, as they distribute more weight away from your legs.

Toilet paper must be packed out with you on much of the trail these days! Thus, the rise of the “backcountry bidet”, which you can make yourself by poking holes in the cap of a plastic liter water bottle. “You come out feeling like you had a full shower,” Spano testifies, and the water you use does not have to be filtered or potable.

Water! Know where your next water source will be. “Camel up at water sources … When you get to a water source, spend some real quality time there soaking your feet, cleaning your bandana, drinking as much water as you possibly feel like you want. Because the only time that your water is going to be ice cold is when you’re at that stream. Anything that you carry with is going to get really warm … Your easiest way to carry water is in your belly.”

When it comes to long distance backpacking, one of the finest pieces of advice Dr. Spano offers is that you should always be upgrading and optimizing your strategy:

“A person who hasn’t changed their backpacking practices in the last 10 years is not a person that I would really want to backpack with. A person who practices medicine the same way they did 10 years ago is not someone I want to practice medicine with. You should always be improving your gear, improving your behaviors, improving the way you approach the same challenge so that you’re a better backpacker as a result.”

Her hour-and-a-half practicum is available on the Wilderness Medicine Society website.

robert-ebert-santos

Roberto Santos is from the remote island of Saipan, in the Commonwealth of the Northern Mariana Islands. He has since lived in Japan and the Hawaiian Islands, and has made Colorado his current home, where he is a web developer, musician, avid outdoorsman and prolific reader. When he is not developing applications and graphics, you can find him performing with the Denver Philharmonic Orchestra, snowboarding Vail or Keystone, soaking in hot springs, or reading non-fiction at a brewery.