Volume 12 Number 4, 1999, Page 198
DKA on Mt. Rainier: A Case Report
Christian D. Herter, MD, CDE
The alpine environment is an unpredictable, sometimes harsh arena that can test the stamina and endurance of any athlete. Those with type 1 diabetes face added challenges, since their metabolic response to exertional, thermal, and barometric stressors is heavily dependent upon exogenous insulin. This report summarizes some of the issues that face mountaineers with diabetes.
In late July 1998, a group of experienced mountaineers, including the author, left Seattle for Mt. Rainier, a 14,600-ft dormant stratovolcano southwest of the Puget Sound basin. Five members of the six-person team had successfully climbed the mountain before, and all had been active in various alpine groups for many years.
Included in the group was A.O., a 26-year-old man who has had type 1 diabetes for 17 years and is treated with continuous subcutaneous insulin infusion (CSII). The author, age 39, also has type 1 diabetes of 13 years' duration and wears an insulin pump. The two climbers with diabetes self-monitored their blood glucose levels frequently and kept in close contact with each other to check blood glucose levels and to make sure there were no problems with the infusion equipment.
The outing organizer had chosen the most popular route for the ascent, which would begin from a trailhead at 5,000 ft. Long climbs such as this are usually done over several days. The first leg of the ascent would involve 5 miles of hiking across a simple snow field to Camp Muir, at 10,000 ft. Some teams rest here for a few hours before ascending; others take an additional day, hoping the extra time will improve their performance at altitude.
Even with the burden of fully loaded packs in the hot sun, the initial leg of this climb was uneventful. Although the group had intended to stop only briefly at Camp Muir, the team leader suggested spending the night, since most of the climbers were sleep-deprived already (many just from trying to prepare for the trip on top of busy work schedules).
The night was calm, and everyone was well-rested by morning. Since warm temperatures and clear skies were predicted, departure from Muir was postponed until sunset as a safety measure. The route would cross over highly crevassed glaciers and under unstable ice cliffs on the way to the summit. These areas would be dangerous to negotiate as temperatures soared under the midday sun.
Some snow bridges along the route had already fallen away from the previous day's heat. In many of these areas, Forest Service rangers had placed narrow ladders across the crevasses. In other places, fallen snow bridges left fissures so vast that new routes had to be forged around them, which added hours to the ascent time.
In addition, falling rock was a continuous threat. At this time of year, snow and ice act like cement to keep precariously perched rocks and boulders stable above climbers. During frosty nighttime hours, these missiles are locked on to their loft ledges. But with warmth from the sun, they rain down on climbing routes. Nighttime was clearly the right time for this ascent.
After packing up camp, all the climbers roped up, checked their safety equipment, harnesses, and accessory climbing gear, and started across the Ingraham Glacier. On leaving base camp, A.O.'s blood glucose level was 120 mg/dl.
During the next hour, 1,000 vertical feet were gained to Ingraham Flats, a level and relatively crevasse-free area high on the glacier. It was 8:00 p.m., and the mountain was beginning to cool. This was a good place to have dinner and consider the rest of the route.
The team members discussed their plans for ascending the next obstacle: the Disappointment Cleaver. This steep nunatak, which was completely visible from their present location, presented the most serious rock-fall danger of the route. Only a month before, a party had been swept off by an avalanche and falling rocks. Clearly, the challenge was to ascend the 1,000-ft crag with just enough of the rapidly fading daylight to see the route in hopes that the few hours of cooling out of direct sunlight was sufficient to reduce the chances of a slide.
Getting to the base of the cleaver required passing over the upper Ingraham Glacier, which had become extensively crevassed. The climbers first had to cross two Forest Service ladders, which was challenging while wearing climbing crampons. The apparently bottomless abyss bridged by these flimsy contrivances managed to raise the resting heart rate of even the most seasoned member of the group.
Once at the base of the cleaver, the expedition was challenged by highly exposed, sometimes ice-covered rock. For the next 1,000 ft, careful attention to the route was the rule. In several places where the rock was too broken or dangerous to climb, the route detoured on to very steep snow slopes thought to be less risky than the unstable volcanic pumice. The going was slow, but strong. As the last vestiges of dusk gave way to a night sky filled with summer constellations, the group arrived at the top of the cleaver and rested.
A.O., normally of a calm temperament, began fiercely cursing. One of the members of his rope team required more time than the others during the last pitch, and he was incensed about it. He also mentioned some nausea, but felt it was related to the less-than-conventional dinner he had consumed earlier: freeze-dried vegetarian chili and slightly wilted turkey and cheese bagels.
The others were a bit surprised by his demeanor but felt that the exertion of the last hour could certainly have resulted in some hypoglycemia. We suggested monitoring blood glucose and took time for a snack.
It was now after 10:00 p.m., and the group was considerably ahead of schedule. At the current pace, the summit was only 56 hours away. We all enjoyed the extended break, taking some time to argue over the names of the brighter stars and taking turns searching for satellites streaking over our frosty perch.
The next pitch would carry the group through the upper Ingraham ice fall, an area where the normally smooth constitution of this glacier was broken into house-sized chunks of ice and rubble. With headlamps lighting the way, the team roped up and set out again, planning another stop with the next 1,000 ft of vertical gain.
A.O. led the second rope. Normally strong and practically inexhaustible, he was now having more trouble maintaining the moderate pace set by our leader. As the group began winding through the upper crevasse fields, A.O. signaled that he required a rest stop, and further, that his nausea was worsening by the minute. He emphatically denied any other symptoms, just nausea and disabling fatigue.
As minutes passed, it became apparent that he required more attention. For the team to congregate in such a dangerous area, anchors needed to be placed and ropes managed carefully. A.O. was found lying on his back, somnolent, and hyperventilating. The group's two physicians made an assessment in the field. This could represent acute mountain sickness (AMS) or a metabolic abnormality resulting from A.O.'s diabetes. The other members of the group were anxious for a diagnosis, since they were beginning to chill in the cold wind of this high altitude.
A.O. was asked about his last blood glucose reading. The initial value of 120 mg/dl, taken as the group left Camp Muir, was the last that had been done. He reported that his glucose meter would not operate at temperatures encountered on the mountain. He had attempted readings both at Ingraham Flats and at the top of the Cleaver, but the device would not run samples, despite A.O. warming test strips and the meter itself using his axillae. The strips could not be interpreted visually, so he had been trying to estimate his insulin needs with no confirmatory data.
The author always carries back-up strips, which can be read visually. A quick sampling showed that A.O.'s current blood glucose was >600 mg/dl. This confirmed that he was suffering from acute insulin deficiency rather than AMS.
Because the last blood glucose reading was in the normal range just 6 hours earlier, the decision was made to administer intravenous insulin. Inspection of A.O.'s insulin pump infusion site showed quite a bit of surrounding erythema, so members of the team performed a site change. Since the infusion reservoir and tubing appeared unaffected, these, along with the insulin from the reservoir, were not changed.
A.O. was clearly too ill to proceed. He started vomiting shortly after the new infusion site had been placed. The climb leader decided that it was unwise to continue with a member of the group in such a medically unstable state, and ordered the team to retreat to a lower, safer area to wait out the night.
When A.O. was able to walk, the group slowly retraced their tracks to the top of Disappointment Cleaver, at 12,400 ft. There, they dug trenches for protection from the wind and kept a close watch over A.O., checking blood glucose levels frequently. The leader had hoped that A.O. would be well enough by morning to down-climb the treacherous cleaver. If not, he would need evacuation by Search and Rescue. At 2:00 a.m., A.O.'s blood glucose had dropped to 50 mg/dl, and he required treatment for hypoglycemia, but felt considerably better.
By morning, A.O. felt as though he had completely recovered. His waking blood glucose was around 180 mg/dl, the nausea had resolved, and he had managed to consume an additional 2 liters of water. He dosed 2 U of insulin through the pump to cover his hyperglycemia, then joined the group for the tricky descent.
A.O. actually led for most of the route back to Camp Muir. As the team began packing up in preparation for the final trip back to the trailhead, however, he noticed recurring nausea and fatigue. He had taken no snack after the bolus on the Cleaver. A blood glucose check showed a surprising level of 345 mg/dl.
At this point, his tubing and reservoir were replaced and filled with insulin from the author's emergency supply, but the infusion site was retained. There was rapid return to his normal level of near-euglycemia, and he was able to finish the hike.
Consideration of the incident suggested a causal relationship. The second day of this expedition was spent largely in the hot sun of Camp Muir. A.O. wore his insulin pump in an area exposed to direct sunlight most of the day. Since insulin is quite temperature-sensitive,1,2 the resulting heat probably diminished its potency. Evidence for this is suggested by his rapid recovery when emergency insulin that had been protected from the heat was administered by syringe.
This theory of bad insulin seems even more likely when taking into consideration the relatively rapid return of hyperglycemia when, after switching infusion sites, A.O. connected his infusion system to the needle using the older insulin. When he replaced the infusion reservoir and filled it with the emergency insulin while retaining the previous infusion site, normal glycemia resulted.
Five Extra Essentials
Outdoor adventurers with diabetes are at risk from more than the elements. They face possible metabolic consequences of too much or too little insulin, so monitoring and safety become life-or-death matters. Since even the tiniest unforeseen problem can result in disaster, an addendum to the famous Ten is suggested below:
If A.O. had carried along some visual strips, he might have been aware of the problem with his insulin before becoming ill. With that kind of advanced warning, this group may not have had to turn back.
2Amaya J, Lee TC, Chichester CO: Biological inactivation of proteins by the Maillard reaction: effect of mild heat on the tertiary structure of insulin. J Agric Food Chem 24:465-67, 1976.
Christian D. Herter, MD, CDE, is an assistant professor of family medicine at the University of Washington Medical Center in Seattle.
Copyright © 1999 American Diabetes Association
Last updated: 12/99