Acute Mountain Sickness and High Altitude Cerebral Edema in Women: A Scoping Review-UIAA Medical Commission Recommendations

Derstine, Mia, Dominique Jean, Beth A. Beidleman, Jacqueline Pichler Hefti, David Hillebrandt, Lenka Horakova, Susi Kriemler, Kasté Mateikaité-Pipiriené, Peter Paal, Alison Rosier, Marija Andjelkovic, and Linda E. Keyes. Acute mountain sickness and high altitude cerebral edema in women: A scoping review-UIAA Medical Commission recommendations. High Alt Med Biol. 24:259-267, 2023. Background: Acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) are illnesses associated with rapid ascent to altitudes over 2,500 m in unacclimatized lowlanders. The aim of this scoping review is to summarize the current knowledge on sex differences in the epidemiology, pathophysiology, symptomatology, and treatment of AMS and HACE, especially in women. Methods and Results: The UIAA Medical Commission convened an international author team to review women's health issues at high altitude and to publish updated recommendations. Pertinent literature from PubMed and Cochrane was identified by keyword search combinations (including AMS, HACE, and high altitude), with additional publications found by hand search. The primary search focus was for articles assessing lowland women sojourning at high altitude. Results: The literature search yielded 7,165 articles, 37 of which were ultimately included. The majority of publications included did not find women at increased risk for AMS or HACE. There was extremely limited sex-specific data on risk factors or treatment. Conclusions: There is a limited amount of data on female-specific findings regarding AMS and HACE, with most publications addressing only prevalence or incidence with regard to sex. As such, general prevention and treatment strategies for AMS and HACE should be used regardless of sex.

High-altitude Illnesses and Air Travel: Pediatric Considerations

Healthy children may present acute mountain sickness (AMS) within a few hours after arrival at high altitudes. In few cases, serious complications may occur, including high-altitude pulmonary edema and rarely high-altitude cerebral edema. Those with preexisting conditions especially involving hypoxia and pulmonary hypertension shall not risk travelling to high altitudes. Newborn from low altitude mothers may have prolonged time to complete postnatal adaptation. The number of children and adolescents traveling on commercial aircrafts is growing, and this poses a need for their treating physicians to be aware of the potential risks of hypoxia while air traveling.

Tetrahydrocurcumin mitigates acute hypobaric hypoxia-induced cerebral oedema and inflammation through the NF-κB/VEGF/MMP-9 pathway

High-altitude cerebral oedema (HACE) is a potentially fatal manifestation of high-altitude sickness and is caused partly by inflammation and the blood-brain barrier disruption. Tetrahydrocurcumin (THC) has been reported to exert effective antioxidative and anti-inflammatory effects; This study sought to elucidate the underlying mechanism of THC in mitigating HACE using a mouse model. Our results revealed that prophylactic administration of THC (40 mg/kg) for 3 days significantly alleviated the increase in brain water content (BWC), interleukin-1β (IL-1β) and TNF-α levels caused by acute hypobaric hypoxia (AHH). Additionally, superoxide dismutase (SOD) activity was increased by THC to enhance the ability to resist hypoxia. Histological and ultrastructural analysis of the cerebrum revealed that THC administration mitigated AHH-induced pericellular oedema and reduced the perivascular space, resulting in the simultaneous remission of oedema and protection of mitochondria in the cerebrum. In vitro, astrocytes exposed to hypoxia (4% O₂ ) for 24 hr exhibited and increase in IL-1β expression followed by an increase in vascular endothelial growth factor (VEGF) levels. Furthermore, THC administration remarkably downregulated VEGF, matrix metallopeptidase-9 (MMP-9), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, both in vivo and in vitro. Our data highlight the potential prophylactic activity of THC in HACE, it effectively mitigates AHH-induced cerebral oedema and inflammation is associated with the inhibition of the NF-κB/ VEGF/MMP-9 pathways.

Inpatient treatment of trekkers and Nepalese workers in the high-altitude environment of Mt. Everest Region 1996-2011: A retrospective analysis

BACKGROUND

The study investigates the diagnoses of inpatients (tourists and Nepali workers) of Kunde Hospital (Mt.Everest region) over 15 years.

METHODS

Records from January 1996 to September 2011 were analyzed concerning date, gender, age group, nationality, purpose of visit, diagnosis, length of treatment, and condition at discharge. Diagnoses were coded according to ICD-10-WHO 2010. Data were analyzed using descriptive statistics and non-parametric tests. P < 0.05 was defined as significant.

RESULTS

479 inpatients were included: 363 (75.8%) males (202 trekkers (42.2%), 277 Nepalese workers (57.8%)). Most suffered from altitude sickness (45.5%), acute gastroenteritis (10.4%) or acute respiratory infection (8.4%). Severe cases of altitude sickness amongst trekkers decreased but increased amongst workers. Severe cases of acute gastroenteritis amongst trekkers increased. Mean length of inpatient treatment was 4.6 days ±2.7 days. 573/2030 days of treatment were caused by altitude sickness. 70 patients were evacuated, 9 died.

CONCLUSION

Altitude illness caused the majority of inpatient treatment and acute gastroenteritis may be an underestimated risk for both groups. Other severe problems were mostly illnesses, not trauma. Improved prevention strategies are needed for both groups. For tourists who often show pre-existing diseases this includes an individual pre-travel expert advice. Nepali workers should be instructed concerning acclimatization.

Diagnosis and prophylaxis for high-altitude acclimatization: Adherence to molecular rationale to evade high-altitude illnesses

Lack of zero side-effect, prescription-less prophylactics and diagnostic markers of acclimatization status lead to many suffering from high altitude illnesses. Although not fully translated to the clinical setting, many strategies and interventions are being developed that are aimed at providing an objective and tangible answer regarding the acclimatization status of an individual as well as zero side-effect prophylaxis that is cost-effective and does not require medical supervision. This short review brings together the twin problems associated with high-altitude acclimatization, i.e. acclimatization status and zero side-effect, easy-to-use prophylaxis, for the reader to comprehend as cogs of the same phenomenon. We describe current research aimed at preventing all the high-altitude illnesses by considering them an assault on redox and energy homeostasis at the molecular level. This review also entails some proteins capable of diagnosing either acclimatization or high-altitude illnesses. The future strategies based on bioinformatics and systems biology is also discussed.

Liver transplantation as a potentially lifesaving measure in neuroblastoma stage 4S

Neuroblastoma (NBL) stage 4s is an incompletely understood phenomenon with variable clinical course. While the majority of patients may undergo spontaneous regression and achieve complete resolution without intensive therapy, a small proportion is at increased risk of developing secondary complications. One such situation is liver insufficiency due to diffuse metastases. We report a patient suffering from NBL 4S who required double lifesaving liver transplantation. Abdominal and respiratory complications due to hepatomegaly are crucial determinants for treatment intensity and duration in 4S NBL [1,2] . We provide an algorithm in order to facilitate the clinical decision when dealing with similar potentially life-threatening events.

Fulminant high altitude blindness

Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes.

Results of a Prospective Observational Study on Mountaineering Emergencies in Western Alps: Mind Your Head

Brustia, Raffaele, Giulia Enrione, Bruna Catuzzo, Luca Cavoretto, Massimo Pesenti Compagnoni, Enrico Visetti, Emmanuel Cauchy, Stefanie Ziegler, and Guido Giardini. Results of a prospective observational study on mountaineering emergencies in Western Alps: mind your head. High Alt Med Biol. 17:116-121, 2016.-

BACKGROUND

In the northern Italian district Valle d'Aosta district during winter and summer season the population can increase up to 170% of the resident population. A prospective monocentric observational registry was held to obtain a precise picture of seasonal mountain-related medical and traumatic major events.

METHODS

From 1st January 2012 to 31st December 2013 all patients admitted to the Aosta Regional Hospital Emergency Room for any event occurred above 2500 m were screened: all those affected by High Altitude Illness, Acute Illness in High Altitude, Trauma, or Cold disease were prospectively included. Activity incidence rate is expressed as the occurrence of mountain-related events per 1000 hours of mountain activity. Event Incidence rate is expressed as the occurrence of new cases per 1000 hours of mountain activity.

RESULTS

Two hundred two patients were included during the study period. Trauma (65.1% vs. 24.6%, p < 0.001) and head commotive injury (48.1% vs. 15.1%, p < 0.001) were more frequent during winter compared to the summer season. High altitude illness (36.9% vs. 9.3%, p < 0.001) and cold pathologies (15.1% vs. 0.1%, p < 0.001) occurred more frequently in summer than in winter. Patients (51.4%) were immediately discharged from emergency room, 8.4% after a 24-hour observation period, and 30.6% required hospitalization. During summer, the event risk is 0.013 per person and 1000 hours of mountain activity, while in winter, event risk amounts to 0.005 per person and 1000 hours of mountain activity.

COMMENTS

High altitude medical events or trauma represent <1% of pathologies observed in the emergency room department of a mountain district in the western Alps. Head commotive injury is the most observed mountain-related event in high altitude, in winter and during ski practice. High altitude illness and cold injuries are observed more frequently in summer, during trekking or climbing activities.