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In Response to Risk Determinants of Acute Mountain Sickness by Lawrence and Reid
WILDERNESS & ENVIRONMENTAL MEDICINE, ], ]]]–]]] (2016)
Letters to the Editor In Response to Risk Determinants of Acute Mountain Sickness by Lawrence and Reid To the Editor: We recently read with profound interest the article titled “Risk Determinants of Acute Mountain Sickness and Summit Success on a 6-Day Ascent of Mount Kilimanjaro (5895 m)” by Lawrence and Reid.1 Authors of the present study have reported a lower incidence of acute mountain sickness (AMS) (52.6% with Lake Louise Score Z3) during a 6-day ascent of Mount Kilimanjaro than described in earlier studies on 4- and 5-day ascents. This incidence of AMS is seen in spite of the fact that 88% of the trekkers were taking acetazolamide to prevent AMS. Presentation of a detailed evaluation of the temporal profile of acetazolamide intake by the trekkers, such as the location along the ascent route when chemoprophylaxis was initiated and stopped, could have aided understanding of the reasons for the lower incidence of AMS and thus led to a wider future application of the findings of the study. Acetazolamide is known to be effective, ideally if started 1 day before ascent in a dosage of 125 mg twice daily, and it should be continued for 2 to 3 days after target altitude has been achieved.2,3 In the present study, to avoid extreme altitude exposure to subjects, trekkers did not spend much time at the summit. The descent of trekkers would have lasted for a few hours, and the expedition doctor would have taken their Lake Louise Score after their return to the base camp (4730 m). This could have added to a recall bias, especially in the background of a possible disturbed sleep during the night of day 5 as all trekkers would have woken early in the morning of day 6 before attempting the summit. As physiologists working in the field of high-altitude medicine, we were interested in knowing the details of physical activity undertaken by the participants during the trek, such as average ascent/descent rate, especially on day 6. Amount of physical activity, rate of ascent, and
actual altitude reached are known to affect the incidence of AMS.4,5 Also, 1 participant was diagnosed with high altitude pulmonary edema (HAPE) at 2900 m on day 2 and was treated with dexamethasone. We were interested to learn if this patient was experiencing concomitant AMS/high altitude cerebral edema. As per Wilderness Medical Society consensus guidelines, dexamethasone is indicated for prevention of HAPE in a susceptible subject and prevention/treatment of AMS and high altitude cerebral edema. Recommendations on its use for treatment of HAPE has been graded weak with low or very low quality evidence.3 Gaurav Sikri, MD Srinivasa Bhattachar, MD Armed Forces Medical College, Pune, India Bikalp Thapa, MD Nepal Army Institute of Health Sciences, Kathmandu, Nepal
References 1. Lawrence JS, Reid SA. Risk determinants of acute mountain sickness and summit success on a 6-day ascent of Mount Kilimanjaro (5895 m). Wilderness Environ Med. 2016;27:78–84. 2. Bärtsch P, Swenson ER. Acute high-altitude illnesses. N Engl J Med. 2013;368:2294–2302. 3. Luks AM, McIntosh SE, Grissom CK, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of acute altitude illness: 2014 Update. Wilderness Environ Med. 2014;25:S4–S14. 4. Roach RC, Maes D, Sandoval D, et al. Exercise exacerbates acute mountain sickness at simulated high altitude. J Appl Physiol. 2000;88:581–658. 5. McDevitt M, McIntosh SE, Rodway G, et al. Risk determinants of acute mountain sickness in trekkers in the Nepali Himalaya: a 24-year follow-up. Wilderness Environ Med. 2014;25:152–159.
Letters to the Editor In Response to Risk Determinants of Acute Mountain Sickness by Lawrence and Reid To the Editor: We recently read with profound interest the article titled “Risk Determinants of Acute Mountain Sickness and Summit Success on a 6-Day Ascent of Mount Kilimanjaro (5895 m)” by Lawrence and Reid.1 Authors of the present study have reported a lower incidence of acute mountain sickness (AMS) (52.6% with Lake Louise Score Z3) during a 6-day ascent of Mount Kilimanjaro than described in earlier studies on 4- and 5-day ascents. This incidence of AMS is seen in spite of the fact that 88% of the trekkers were taking acetazolamide to prevent AMS. Presentation of a detailed evaluation of the temporal profile of acetazolamide intake by the trekkers, such as the location along the ascent route when chemoprophylaxis was initiated and stopped, could have aided understanding of the reasons for the lower incidence of AMS and thus led to a wider future application of the findings of the study. Acetazolamide is known to be effective, ideally if started 1 day before ascent in a dosage of 125 mg twice daily, and it should be continued for 2 to 3 days after target altitude has been achieved.2,3 In the present study, to avoid extreme altitude exposure to subjects, trekkers did not spend much time at the summit. The descent of trekkers would have lasted for a few hours, and the expedition doctor would have taken their Lake Louise Score after their return to the base camp (4730 m). This could have added to a recall bias, especially in the background of a possible disturbed sleep during the night of day 5 as all trekkers would have woken early in the morning of day 6 before attempting the summit. As physiologists working in the field of high-altitude medicine, we were interested in knowing the details of physical activity undertaken by the participants during the trek, such as average ascent/descent rate, especially on day 6. Amount of physical activity, rate of ascent, and
actual altitude reached are known to affect the incidence of AMS.4,5 Also, 1 participant was diagnosed with high altitude pulmonary edema (HAPE) at 2900 m on day 2 and was treated with dexamethasone. We were interested to learn if this patient was experiencing concomitant AMS/high altitude cerebral edema. As per Wilderness Medical Society consensus guidelines, dexamethasone is indicated for prevention of HAPE in a susceptible subject and prevention/treatment of AMS and high altitude cerebral edema. Recommendations on its use for treatment of HAPE has been graded weak with low or very low quality evidence.3 Gaurav Sikri, MD Srinivasa Bhattachar, MD Armed Forces Medical College, Pune, India Bikalp Thapa, MD Nepal Army Institute of Health Sciences, Kathmandu, Nepal
References 1. Lawrence JS, Reid SA. Risk determinants of acute mountain sickness and summit success on a 6-day ascent of Mount Kilimanjaro (5895 m). Wilderness Environ Med. 2016;27:78–84. 2. Bärtsch P, Swenson ER. Acute high-altitude illnesses. N Engl J Med. 2013;368:2294–2302. 3. Luks AM, McIntosh SE, Grissom CK, et al. Wilderness Medical Society practice guidelines for the prevention and treatment of acute altitude illness: 2014 Update. Wilderness Environ Med. 2014;25:S4–S14. 4. Roach RC, Maes D, Sandoval D, et al. Exercise exacerbates acute mountain sickness at simulated high altitude. J Appl Physiol. 2000;88:581–658. 5. McDevitt M, McIntosh SE, Rodway G, et al. Risk determinants of acute mountain sickness in trekkers in the Nepali Himalaya: a 24-year follow-up. Wilderness Environ Med. 2014;25:152–159.