Women at Altitude: Menstrual-Cycle Phase, Menopause, and Exogenous Progesterone Are Not Associated with Acute Mountain Sickness.

Gardner, Laurel, Linda E. Keyes, Caleb Phillips, Elan Small, Tejaswi Adhikari, Nathan Barott, Ken Zafren, Rony Maharjan, and James Marvel. Women at altitude: Menstrual-cycle phase, menopause, and exogenous progesterone are not associated with acute mountain sickness. High Alt Med Biol. 00:000-000, 2024. Background: Elevated progesterone levels in women may protect against acute mountain sickness (AMS). The impact of hormonal contraception (HC) on AMS is unknown. We examined the effect of natural and exogenous progesterone on the occurrence of AMS. Methods: We conducted a prospective observational convenience study of female trekkers in Lobuche (4,940 m) and Manang (3,519 m). We collected data on last menstrual period, use of exogenous hormones, and development of AMS. Results: There were 1,161 trekkers who met inclusion criteria, of whom 307 (26%) had AMS. There was no significant difference in occurrence of AMS between women in the follicular (28%) and the luteal (25%) phases of menstruation (p = 0.48). The proportion of premenopausal (25%) versus postmenopausal women (30%) with AMS did not differ (p = 0.33). The use of HC did not influence the occurrence of AMS (HC 23% vs. no HC 26%, p = 0.47), nor did hormonal replacement therapy (HRT) (HRT 11% vs. no HRT 31%, p = 0.13). Conclusion: We found no relationship between menstrual-cycle phase, menopausal status, or use of exogenous progesterone and the occurrence of AMS in trekkers and conclude that hormonal status is not a risk factor for AMS. Furthermore, women should not be excluded from future AMS studies based on hormonal status.

Prior Ambulatory Mild Coronavirus Disease 2019 Does Not Increase Risk of Acute Mountain Sickness.

Small, Elan, Caleb Phillips, William Bunzel, Lakota Cleaver, Nishant Joshi, Laurel Gardner, Rony Maharjan, and James Marvel. Prior ambulatory mild coronavirus disease 2019 does not increase risk of acute mountain sickness. High Alt Med Biol. 24:201-208, 2023. Background: Given its long-term morbidity, understanding how prior coronavirus disease 2019 (COVID-19) may affect acute mountain sickness (AMS) susceptibility is important for preascent risk stratification. The objective of this study was to examine if prior COVID-19 impacts risk of AMS. Materials and Methods: This was a prospective observational study conducted in Lobuje (4,940 m) and Manang (3,519 m), Nepal, from April to May 2022. AMS was defined by the 2018 Lake Louise Questionnaire criteria. COVID-19 severity was defined using the World Health Organization-developed criteria. Results: In the Lobuje cohort of 2,027, 46.2% of surveyed individuals reported history of COVID-19, with 25.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.6) or moderate AMS (p = 1.0). In the Manang cohort of 908, 42.8% reported history of COVID-19, with 14.7% AMS point-prevalence. There was no significant relationship between prior ambulatory mild COVID-19 and AMS (p = 0.3) or moderate AMS (p = 0.4). Average months since COVID-19 was 7.4 (interquartile range [IQR] 3-10) for Lobuje, 6.2 (IQR 3-6) for Manang. Both cohorts rarely exhibited moderate COVID-19 history. Conclusions: Prior ambulatory mild COVID-19 was not associated with increased risk of AMS and should not preclude high-altitude travel.

19-Year-Old with Sudden Onset Left Testicular Pain.

CASE PRESENTATION: A previously healthy 19-year-old man presented to the emergency department with severe, sudden onset of left testicular pain. Physical exam revealed a left high-riding, horizontally oriented testicle without cremasteric reflex. Point-of-care ultrasound was used to confirm the diagnosis of testicular torsion, as well as to guide manual detorsion, verifying return of blood flow after reduction. DISCUSSION: Testicular torsion is a urologic emergency in which testicular viability is time dependent. Point-of-care ultrasound can be an important and helpful tool to not only confirm suspicion but help guide adequacy of blood flow return after manual detorsion in conjunction with comprehensive ultrasound.

Older Age as a Predictive Risk Factor for Acute Mountain Sickness.

BACKGROUND: Older populations are increasing and comprise a substantial portion of high-altitude travelers. Aging physiology may influence susceptibility to acute mountain sickness, though prior research remains inconclusive. The goal of this study was to investigate the relationship between increasing age and acute mountain sickness. METHODS: This study was a pooled analysis of 5 prospective randomized controlled trials conducted at White Mountain, California from 2010, 2016-2019 with identical 4-hour rapid ascent from 1242 m to overnight sojourn at 3810 m. Acute mountain sickness was defined by the 2018 Lake Louise Questionnaire criteria. RESULTS: There were 491 participants analyzed, 234 (48%) diagnosed with acute mountain sickness and 71 (14%) with moderate acute mountain sickness. Mean age was 37 years (±13). There was no significant correlation between Lake Louise Questionnaire severity and age (r = -0.02; 95% confidence interval [CI], -0.11-0.07, P = .7), 40-year-old dichotomy (t = -0.6; 95% CI, -0.53-0.28, P = .6), or decade of life (P = .4). Logistic regression found no increased odds of acute mountain sickness for increasing age by decade of life (odds ratio [OR] 1.0; 95% CI, 0.97-1.0) or 40-year-old dichotomy (OR 1.4; 95% CI, 0.97-2.1). A history of acute mountain sickness increased odds of acute mountain sickness (OR 3.2; 95% CI, 1.5-7.7). CONCLUSIONS: Older age was not associated with incidence nor severity of acute mountain sickness. A history of altitude illness increased odds of acute mountain sickness and should be used for pre-ascent risk stratification.

Predictive Capacity of Pulmonary Function Tests for Acute Mountain Sickness.

Small, Elan, Nicholas Juul, David Pomeranz, Patrick Burns, Caleb Phillips, Mary Cheffers, and Grant S. Lipman. Predictive capacity of pulmonary function tests for acute mountain sickness. High Alt Med Biol. 22: 193-200, 2021. Background: Pulmonary function as measured by spirometry has been investigated at altitude with heterogenous results, though data focused on spirometry and acute mountain sickness (AMS) are limited. The objective of this study was to investigate the capacity of pulmonary function tests (PFTs) to predict the development of AMS. Materials and Methods: This study was a blinded prospective observational study run during a randomized controlled trial comparing acetazolamide, budesonide, and placebo for AMS prevention on White Mountain, CA. Spirometry measurements of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow were taken at a baseline altitude of 1,250 m, and the evening of and morning after ascent to 3,810 m. Measurements were assessed for correlation with AMS. Results: One hundred three participants were analyzed with well-matched baseline demographics and AMS incidence of 75 (73%) and severe AMS of 48 (47%). There were no statistically significant associations between changes in mean spirometry values on ascent to high altitude with incidence of AMS or severe AMS. Lake Louise Questionnaire scores were negatively correlated with FVC (r = -0.31) and FEV1 (r = -0.29) the night of ascent. Baseline PFT had a predictive accuracy of 65%-73% for AMS, with a receiver operating characteristic of 0.51-0.65. Conclusions: Spirometry did not demonstrate statistically significant changes on ascent to high altitude, nor were there significant associations with incidence of AMS or severe AMS. Low-altitude spirometry did not accurately predict development of AMS, and it should not be recommended for risk stratification.

Apostle Islands National Lakeshore: A Review of Search and Rescue and Emergency Medical Services Operations, 2006-2015.

INTRODUCTION: Apostle Islands National Lakeshore (APIS) lies at the northern tip of Wisconsin and is home to a network of 21 islands along Lake Superior. The goal of this report is to investigate search and rescue (SAR) and emergency medical services (EMS) trends at APIS in an effort to improve visitor safety and resource allocation. METHODS: This study is a retrospective analysis reviewing APIS SAR reports and annual EMS summary reports from January 1, 2006, to December 31, 2015. Information related to incident type, incident date, individual demographic characteristics and activities, injury/illness type, cost, and contributing factors were recorded and analyzed in frequency tables. RESULTS: From 2006 to 2015, APIS SAR conducted 133 total missions assisting 261 individuals-200 not injured/ill, 57 injured/ill, and 4 fatalities. Median cost per SAR incident involving aircraft totaled $21,695 (range: $2,993-141,849), whereas incidents not involving aircraft had a median cost of $363 (range: $35-8,830). Nonmotorized boating was the most common activity resulting in SAR incidents. All 4 fatalities were attributed to drowning while kayaking or swimming. Cold-related injury/illness accounted for nearly half of all injuries/illnesses (45%) with the most commonly reported contributing factor being high winds. EMS responded to a total of 134 incidents. Trauma and first aid accounted for 43% and 34% of EMS workload, respectively. CONCLUSIONS: Overall, this study highlights the hazards associated with the frigid and rough conditions of Lake Superior. The reported results aim to help APIS personnel more saliently convey risks to visitors and plan appropriately in an effort to decrease the need for future rescues.