Heatstroke

Heat stress sensitizes zebrafish embryos to neurological and cardiac toxicity

Global warming increases the risk of dangerous heat waves, which may have deleterious effects on humans and wildlife. Here, we have utilized zebrafish embryos as a model to analyze heat stress and effect of chemical compounds on responses to heat stress. The temperature adaptation limit of zebrafish embryos was 37 °C in behavioural test and 38 °C in cardiac test. Polyaromatic hydrocarbon phenanthrene completely blocked the behavioural adaptation to heat stress. Interestingly, the cardiotoxic effects of lapatinib, phenanthrene and paclitaxel were induced by heat stress. Taken together, our data indicates that motility and cardiac function of zebrafish embryos can be utilized as a model to analyze modulatory effects of compounds on heat stress.

Altered static brain activity and functional connectivity after heat stroke

This study aimed to investigate the alteration of brain function based on resting-state functional MRI in patients after heat stroke. This study included 10 cases of patients after heat stroke and 10 cases of healthy controls. Abnormal brain function was calculated using amplitude of low-frequency fluctuations (ALFF) and degree centrality analysis, as well as functional connectivity analysis based on regions of interest (ROI). Correlation analyses were performed to evaluate the association between brain function changes and clinical scales. Combining ALFF and degree centrality results, the decreased brain regions included the left cuneus and the right angular gyrus, while the increased brain regions included the right cerebellar_Crus1. Using the left cuneus with significant differences in ALFF and degree centrality as ROI, the functional connectivity results revealed decreased brain regions including bilateral lingual gyrus, bilateral postcentral cingulate gyrus, and left precentral gyrus. The degree centrality value of the right cerebellar_Crus1 was positively correlated with glasgow coma scale (GCS) scores ( r  = 0.726, P  = 0.027), and the functional connectivity value of the right posterior cingulate gyrus was positively correlated with GCS scores ( r  = 0.717, P  = 0.030). Heat stroke patients exhibit abnormal activity in multiple brain regions, which has important clinical significance for evaluating the severity of the disease.

Risk factors of early death in heat stroke and the challenges of emergency care in Hungary - a case series study

BACKGROUND AND AIM

The increasing frequency of heat waves worldwide is a major challenge for emergency care providers worldwide. The aim of this study was to analyze the clinical features, treatment options, and early outcomes of heat stroke patients presenting to a large academic emergency department (ED) in Hungary and to provide guidance in management for other emergency professionals.

METHODS

Patients presenting to the ED between June 1, 2024, and July 31, 2024, with a body temperature above 40 °C were analyzed in a retrospective cohort study. Data collection included demographic, clinical and laboratory parameters. Predictors of mortality were analyzed with Mann-Whitney U test.

RESULTS

Eight patients were included in our analysis. Three patients died in the ED (37.5%). Patients who died had significantly lower pH (7.07 vs. 7.4, p = 0.036), higher potassium (7.3 vs. 3.2 mmol/L, p = 0.036), higher calcium (1.19 vs. 0.97 mmol/L, p = 0.036), higher lactate (10.9 vs. 3.5 mmol/L, p = 0.036) and higher PaCO2 (57.2 vs. 28 mmHg, p = 0.036) at admission compared to those who did not die.

CONCLUSIONS

The risk of heat stroke due to climate change-induced heat stress and the consequent thermoregulatory disruption may now be significant in temperate climate zones where it was not previously present. Standardization of differential diagnostic and therapeutic procedures could reduce mortality. pH, potassium, lactate and calcium levels may play an important role in predicting the outcome of heat stroke.

Effects of normal saline versus lactated Ringer's solution on organ function and inflammatory responses to heatstroke in rats

BACKGROUND

Heatstroke is a life-threatening condition characterized by severe hyperthermia and multiple organ dysfunction. Both normal saline (NS) and lactated Ringer's solution (LR) are commonly used for cooling and volume resuscitation in heatstroke patients; however, their specific impacts on patient outcomes during heatstroke management are poorly understood. Given that the systemic inflammatory response and multiple-organ damage caused by heat toxicity are the main pathophysiological features of heatstroke, the aim of this study was to evaluate the effects of NS and LR on the production of inflammatory cytokines and the functional and structural integrity of renal and cardiac tissues in a rat model of heatstroke.

METHODS

Fifty-five male Sprague‒Dawley rats were randomly divided into four groups: cold NS or LR infusion postheatstroke (4 ℃, 4 ml/100 g, over 10 min) and NS or LR infusion without heatstroke induction (control groups). Vital signs, arterial blood gases, inflammatory cytokines, and renal and cardiac function indicators, such as serum creatinine and cTnI, were monitored after treatment. Tissue samples were analysed via HE staining, electron microscopy, and fluorescence staining for apoptosis markers, and protein lysates were used for Western blotting of pyroptosis-related proteins.

RESULTS

Compared with LR-treated heatstroke rats, NS-treated heatstroke rats presented lower mean arterial pressures, worsened metabolic acidosis, and higher levels of IL-6 and TNF-α in both the serum and tissue. These rats also presented increased serum creatinine, troponin, catecholamines, and NGAL and reduced renal clearance. Histological and ultrastructural analyses revealed more severe tissue damage in NS-treated rats, with increased apoptosis and increased expression of NLRP3/caspase-1/GSDMD signalling molecules. Similar differences were not observed between the control groups receiving either NS or LR infusion. One NS-treated heatstroke rat died within 24 h, whereas all the LR-treated and control rats survived.

CONCLUSIONS

NS resuscitation in heat-exposed rats significantly promotes metabolic acidosis and the inflammatory response, leading to greater functional and structural organ damage than does LR. These findings underscore the necessity of selecting appropriate resuscitation fluids for heatstroke management to minimize organ damage and improve outcomes.

Climate change distress and impairment in Germany

Introduction

Climate change has been widely recognized as one of the most challenging problems facing humanity and it imposes serious mental health threats. It is important, however, to differentiate between the affective experience of distress over climate change and the functional impairments associated with climate change. Such a distinction is crucial because not all negative affective states are pathological, and they might even motivate pro-environmental behavior. Functional impairments, like not being able to work or maintaining social relationships, however, might require immediate treatment. This study assesses climate change distress and climate change impairment within the population of Germany using a population-representative sample. The results identify vulnerable subgroups and thereby can help to facilitate the development of target group specific intervention programs. Furthermore, this study explores whether climate change distress and climate change impairment are associated with general health, physical health, mental health, and diverse health behaviors.

Methods

Study participants were drawn from a panel which is representative of the German-speaking population in Germany with Internet access. Participants answered a series of questionnaires regarding their climate change distress, climate change impairment, general health, physical health, mental health, and diverse health behaviors. To evaluate differences between subgroups, Bayesian independent samples t-tests were calculated. To evaluate associations between constructs, Bayesian correlations were calculated.

Results

Especially women, younger people, people from West Germany, and people with a high level of formal education seem to experience higher levels of climate change distress. Regarding climate change impairment, the results suggest that especially women, older people, people from West Germany, people with a low level of formal education, people with a low or middle social status, and people with an inadequate/problematic health literacy seem to experience higher levels of climate change impairment. Furthermore, climate change distress and climate change impairment were weakly and differently associated with general health, physical health, mental health, and diverse health behaviors.

Discussion

Climate change distress and impairment are not evenly distributed within German society. The results of this study provide a starting point for the development of target group specific intervention programs.

Concurrent ozone and high temperature exacerbates nasal epithelial barrier damage in allergic rhinitis mice: Insights from the nasal transcriptome and nasal microbiota

The global ambient temperature has been rising in recent decades and high temperature is usually accompanied by ozone (O3) pollution. Environmental change is an underlying factor for the increased prevalence of respiratory allergic disease. However, the potential mechanisms are complex and remain elusive. This study was performed to reveal toxic effects and molecular mechanisms of O3 or/and high temperature induced allergic rhinitis (AR) deterioration. The results indicated that O3 and high temperature co-exposure exacerbated rhinitis symptoms, destroyed ultrastructure of nasal mucosa and down-regulated the expression of nasal epithelial barrier structural proteins ZO-1 and occludin. Moreover, the levels of total protein and lactate dehydrogenase (LDH) in nasal lavage fluid and the levels of IL-1β and TNF-α in serum also exhibited a significant upward trend. Transcriptomic analysis revealed that immune and inflammatory signaling pathways such as IL-17 signaling pathway was involved in the combined toxicity of O3 and high temperature. Microbiome examination showed that Prevotella and Elizabethkingia were linked to nasal injury. What's more, spearman correlation analysis revealed correlations among nasal microbiota dysbiosis, inflammation and injury. To sum up, the present study assessed the combined toxicity of O3 and high temperature and found potential mechanisms, which provided important experimental evidence for making preventive intervention strategies and protecting vulnerable populations.

Exacerbation of Hepatic Damage in Endothelial Aquaporin 1 Transgenic Mice after Experimental Heatstroke

Heatstroke induces fluid loss and electrolyte abnormalities owing to high ambient temperature (AT) and relative humidity (RH). Aquaporin 1 (AQP1) is a key protein for water homeostasis; however, its role in heatstroke remains unclear. This study examines endothelial AQP1 in Tie2-Cre/LNL-AQP1 double transgenic (dTG) mice with upregulated Aqp1 in endothelial cells. For experimental heatstroke, mice were exposed to 41 °C AT and >99% RH. Blood, brain, kidney, and liver samples were collected 24 h later. Blood was analyzed for electrolytes and tissue damage markers, and organs were examined using morphological and immunohistological staining for 3-nitrotyrosine (3-NT), AQP1, and Iba-1. No difference in Aqp1 expression was observed in the whole brain; however, it was detected in dTG mice after capillary deprivation. AQP1 immunostaining revealed immunoreaction in blood vessels. After heat exposure, wild-type and dTG mice showed electrolyte abnormalities compared with non-heatstroke wild-type mice. Hepatic damage markers were significantly higher in dTG mice than in wild-type mice. Hematoxylin-eosin staining and 3-NT immunoreactivity in the liver indicated hepatic damage. The number of Iba-1-positive cells adherent to hepatic vasculature was significantly higher in dTG mice than in wild-type mice. This study is the first to suggest that endothelial AQP1 contributes to hepatic damage after heatstroke.

Surviving a classic heat stroke/hyperthermia > 42 °C - a case report

INTRODUCTION

Classic heat stroke is a severe trauma which can lead to multi-organ dysfunctions and is associated with a high mortality.

CASE PRESENTATION

In this case report we present a 73-year-old patient with a classic heat stroke. His initial core body temperature was over 42 °C and he had a GCS of 3. Due to severe burn injuries the patient was transferred to a specialized burn center. The patient developed different organ failures and showed a prolonged course on the intensive care unit. Although the patient demonstrated different impaired organ systems, he recovered completely after receiving painstaking supportive therapy.

CONCLUSIONS

This is a rare case of a patient who fully recovered after a heat stroke with a temperature over 42 °C and severe sequelae.

Motor-free telerobotic endomicroscopy for steerable and programmable imaging in complex curved and localized areas

Intraluminal epithelial abnormalities, potential precursors to significant conditions like cancer, necessitate early detection for improved prognosis. We present a motor-free telerobotic optical coherence tomography (OCT) endoscope that offers high-resolution intraluminal imaging and overcomes the limitations of traditional systems in navigating curved lumens. This system incorporates a compact magnetic rotor with a rotatable diametrically magnetized cylinder permanent magnet (RDPM) and a reflector, effectively mitigating thermal and electrical risks by utilizing an external magnetic field to maintain temperature increases below 0.5 °C and generated voltage under 0.02 mV. Additionally, a learning-based method corrects imaging distortions resulting from nonuniform rotational speeds. Demonstrating superior maneuverability, the device achieves steerable angles up to 110° and operates effectively in vivo, providing distortion-free 3D programmable imaging in mouse colons. This advancement represents a significant step towards guidewire-independent endomicroscopy, enhancing both safety and potential patient outcomes.

Pickleball Primer: An Overview of Common Injuries, Treatment, and Optimization Strategies in Pickleball Athlete

Pickleball is one of the fastest growing sports in the United States with millions of players nationwide. It is a relatively appealing sport because of its ease of access, low impact, and highly social atmosphere, allowing players of all ages to participate. As the number of players continues its dramatic increase, player injuries are certain to increase in turn. There is little to no orthopaedic research on pickleball-related injuries and a paucity of data regarding treatment and prevention strategies. This summary was designed to familiarize orthopaedic surgeons with the basics of the sport and highlight potential pickleball-related injuries they may encounter in practice.

Acute liver failure: A practical update

Acute liver failure is a rare and dynamic condition, with a broad aetiology and an incompletely understood pathophysiology. Management of this life-threatening disease requires critical care and organ support and frequently early liver transplantation. Proper identification, prevention and treatment of complications such as intracranial hypertension and sepsis are critical to optimising outcomes. The identification of the cause of acute liver failure and the prompt initiation of the aetiological treatment can also improve prognosis. Survival has progressively improved in parallel to advances in medical treatment. Intracranial hypertension complicating hepatic encephalopathy is less frequent than in the past and intracranial pressure monitoring now relies on non-invasive techniques. Current prognostic models have good accuracy to identify patients who will die without liver transplantation but are not able to identify those in whom transplantation is futile. New prognostic markers to select patients for transplantation are still in the pipeline. Therapeutic plasma exchange and, in some centers, early renal replacement therapy are well established treatments for the disease. The use of other artificial liver devices in clinical practice is not supported by evidence. This review is intended to provide a clinical update on the management of acute liver failure, incorporating the most recent advances in the field.

The effect of 8-day oral taurine supplementation on thermoregulation during low-intensity exercise at fixed heat production in hot conditions of incremental humidity

PURPOSE

To determine the effect of taurine supplementation on sweating and core temperature responses, including the transition from compensable to uncompensable heat stress, during prolonged low-intensity exercise of a fixed-heat production (~ 200W/m2) in hot conditions (37.5 °C), at both fixed and incremental vapour-pressure.

METHODS

Fifteen females (n = 3) and males (n = 12; 27 ± 5 years, 78 ± 9 kg, V ˙ O2max 50.3 ± 7.8 mL/kg/min), completed a treadmill walking protocol (~ 200W/m2 heat production [Ḣprod]) in the heat (37.5 ± 0.1 °C) at fixed-(16-mmHg) and ramped-humidity (∆1.5-mmHg/5-min) following 1 week of oral taurine supplementation (50 mg/kg/bm) or placebo, in a double-blind, randomised, cross-over design. Participants were assessed for whole-body sweat loss (WBSL), local sweat rate (LSR), sweat gland activation (SGA), core temperature (Tcore), breakpoint of compensability (Pcrit) and calorimetric heat transfer components. Plasma volume and plasma taurine concentrations were established through pre- and post-trial blood samples.

RESULTS

Taurine supplementation increased WBSL by 26.6% and 5.1% (p = 0.035), LSR by 15.5% and 7.8% (p = 0.013), SGA (1 × 1 cm) by 32.2% and 29.9% (p < 0.001) and SGA (3 × 3 cm) by 22.1% and 17.1% (p = 0.015) during the fixed- and ramped-humidity exercise periods, respectively. Evaporative heat loss was enhanced by 27% (p = 0.010), heat-storage reduced by 72% (p = 0.024) and Pcrit was greater in taurine vs placebo (25.0-mmHg vs 21.7-mmHg; p = 0.002).

CONCLUSION

Taurine supplementation increased sweating responses during fixed Ḣprod in hot conditions, prior to substantial heat strain and before the breakpoint of compensability, demonstrating improved thermoregulatory capacity. The enhanced evaporative cooling and reduced heat-storage delayed the subsequent upward inflection in Tcore-represented by a greater Pcrit-and offers a potential dietary supplementation strategy to support thermoregulation.

Prognostic significance of nadir platelet count in patients with heatstroke: A multi-center retrospective study

BACKGROUND

Heatstroke (HS), associated with the early activation of the coagulation system and frequently presenting with thrombocytopenia, poses a significant healthcare challenge. Understanding the relationship of nadir platelet count (PLT) within 24 h for adverse outcomes in HS patients is crucial for optimizing management strategies.

METHODS

This retrospective cohort study, conducted in six tertiary care hospitals, involved patients diagnosed with HS and admitted to the emergency departments. The primary and secondary outcomes included in-hospital mortality and various acute complications, respectively, with logistic regression models utilized for assessing associations between nadir PLT and outcomes. The PLT count change curve was described using a generalized additive mixed model (GAMM), with additional analyses involving body temperature (BT) at 2 h also conducted.

RESULTS

Of the 152 patients included, 19 (12.5%) died in-hospital. The median nadir PLT within 24 h was 99.5 (58.8-145.0)*10^9/L. Notably, as a continuous variable (10*10^9/L), nadir PLT was significantly associated with in-hospital mortality (OR 0.76; 95% CI 0.64-0.91; P = 0.003) and other adverse outcomes like acute kidney and liver injury, even after adjustment for confounders. GAMM revealed a more rapid and significant PLT decline in the non-survival group over 24 h, with differential PLT dynamics also observed based on BT at 2 h.

CONCLUSIONS

Nadir PLT within 24 h were tied to in-hospital mortality and various adverse outcomes in HS patients. Early effective cooling measures demonstrated a positive impact on these associations, underscoring their importance in patient management.

Rebound Hyperthermia in Exertional Heat Stroke

Exertional heat stroke (EHS) is a life-threatening condition requiring rapid reversal of hyperthermia to prevent poor health outcomes. Current treatment protocols aim for a cooling rate of 0.15 C/min using various modalities. This case report details a 22-year-old male who, despite initial successful cooling measures, experienced rebound hyperthermia, necessitating the use of endovascular cooling (EVC). The patient collapsed during a 19.3 km (12-mile) ruck march in Fort Moore, Georgia, with an initial core temperature of 41.6ºC. Conventional cooling methods, including ice sheets and chilled intravenous saline, adequately cooled the patient to target temperatures; however, discontinuation of cooling methods resulted in rebound hyperthermia. Endovascular cooling was eventually initiated, resulting in euthermia after 36 hours of continued use. During his hospital admission, the patient was evaluated thoroughly for underlying etiologies contributing to his rebound hyperthermia. This workup did not yield any concerning pathology, except for bilateral foot cellulitis noted on physical examination, which was subsequently managed with antibiotics. Despite initial complications, the patient recovered within 5 days and returned to duty after 2 months. Several case reports have been published regarding the use of EVC in the management of EHS. These reports, however, describe its use in initial management of EHS or in cases where hyperthermia was refractory to other conventional cooling methods. To our knowledge, this is the first report of its kind highlighting its successful implementation in rebound hyperthermia. Early recognition and initiation of cooling measures are critical in EHS cases. Future directions include developing EHS-specific EVC protocols for patients experiencing refractory or rebound hyperthermia.

APTT and D-dimer as biomarkers for heatstroke in patients with severe heat-related illnesses

The objective of this study was to analyze the changes of activated partial thromboplastin time (APTT) and D-dimer in severe heatstroke (HS) patients and their value in identifying HS patients and to analyze clinical features and early laboratory test results of heat-related illnesses. Forty-five patients with heat-related illnesses who were admitted to the Department of Emergency and Intensive Care Medicine of Suining Central Hospital from June 2022 to April 2023 were retrospectively analyzed. Patients were divided into 3 groups based on their clinical diagnosis: classic HS group, exertional HS group, and control group. General date and laboratory test results were collected, especially APTT and D-dimer. The receiver operating characteristic curve was used to analyze D-dimer and APTT. : There were differences in gender distribution among the 3 groups. Exertional HS was dominated by male patients, and classic HS was dominated by elderly patients. Binary logistic regression analysis of coagulation index showed a significant correlation between D-dimer and APTT and HS. The receiver operating characteristic curve results showed that APTT and D-dimer had high sensitivity and specificity in the identification of HS with an area under the curve (AUC) of 0.846, sensitivity of 97%, and specificity of 58.3% for APTT and an AUC of 0.861, sensitivity of 72%, and specificity of 91.7% for D-dimer (D-dimer + APTT [AUC, 0.929; sensitivity, 81.8%-91.7%; P < .001]). : The mortality rate of HS is high, and early diagnosis is particularly important. APTT and D-dimer may be used as markers assisting in identifying HS.

A ratiometric fluorescent probe with dual-targeting capability for heat shock imaging

HSO3- is an important reactive sulfur species that maintains the normal physiological activities of living organisms and participates in a variety of redox homeostatic processes. It has been found that changes in HSO3- levels is closely related to the heat stroke phenomenon of the organism. Heat stroke causes damage to normal cells, which in turn causes damage to the body and even death. It is crucial to accurately monitor and track the physiological behavior of HSO3- during heat stroke. Herein, a ratiometric multifunctional fluorescent probe DRM-SO2 with dual-targeting ability to rapidly and precisely recognize HSO3- being constructed based on the FRET mechanism. DRM-SO2 has extra Large Stokes shift (216 nm), very high sensitivity (DL = 12.2 nM), fast response time and good specificity. When DRM-SO2 undergoes Michael addition with HSO3-, the fluorescence emission peak was blue-shifted from 616 nm to 472 nm, and a clear ratiometric signal appeared. The interaction between lysosomes and mitochondria in maintaining cellular homeostasis was investigated by the dual-targeting ability of the probe using HSO3- as a mediator. DRM-SO2 achieved successful targeting and real-time monitoring of exogenous and endogenous HSO3- in the cells. More importantly, imaging experiments in heat stroke mice revealed high HSO3- expression in intestinal tissues. This provides new ideas and research tools for early prevention of heat stroke-induced diseases such as intestinal injuries. In addition, the semi-quantitative monitoring experiments for paper-based visualization of HSO3- make the probe promising for the design of portable detectors.

HMGB1 released from pyroptotic vascular endothelial cells promotes immune disorders in exertional heatstroke

BACKGROUND AND OBJECTIVE

Exertional heatstroke (EHS) mainly occurs in healthy young people with rapid onset and high mortality. EHS immune disorders can cause systemic inflammatory responses and multiple organ failure; however, the underlying mechanisms remain unclear. As high mobility group box 1 (HMGB1) is a prototypical alarmin that activates inflammatory and immune responses, this study aimed to investigate the effect and mechanism of HMGB1 in the pathogenesis of EHS.

METHODS

Peripheral blood mononuclear cell (PBMC) transcriptome sequencing of healthy volunteers, classical heatstroke patients, and EHS patients was performed. A mouse model of EHS was established and murine tissue damage was evaluated by H&E staining. HMGB1 localization and release were visualized using immunofluorescence staining. Human umbilical vein endothelial cells (HUVECs) and THP-1 cells were co-cultured to study the effects of HMGB1 on macrophages. A neutralizing anti-HMGB1 antibody was used to evaluate the efficacy of EHS treatment in mice.

RESULTS

Plasma and serum HMGB1 levels were significantly increased in EHS patients or mice. EHS-induced endothelial cell pyroptosis promoted HMGB1 release in mice. HMGB1 derived from endothelial cell pyroptosis enhanced macrophage pyroptosis, resulting in immune disorders under EHS conditions. Administration of anti-HMGB1 markedly alleviated tissue injury and systemic inflammatory responses after EHS.

CONCLUSIONS

The release of HMGB1 from pyroptotic endothelial cells after EHS promotes pyroptosis of macrophages and systemic inflammatory response, and HMGB1-neutralizing antibody therapy has good application prospects for EHS.

Cardiovascular magnetic resonance feature tracking derived strain analysis can predict return to training following exertional heatstroke

BACKGROUND

Exertional heatstroke (EHS) is increasingly common in young trained soldiers. However, prognostic markers in EHS patients remain unclear. The objective of this study was to evaluate cardiovascular magnetic resonance (CMR) feature tracking derived left ventricle (LV) strain as a biomarker for return to training (RTT) in trained soldiers with EHS.

METHODS

Trained soldiers (participants) with EHS underwent CMR cine sequences between June 2020 and August 2023. Two-dimensional (2D) LV strain parameters were derived. At 3 months after index CMR, the participants with persistent cardiac symptoms including chest pain, dyspnea, palpitations, syncope, and recurrent heat-related illness were defined as non-RTT. Multivariable logistic regression analysis was used to develop a predictive RTT model. The performance of different models was compared using the area under curve (AUC).

RESULTS

A total of 80 participants (median age, 21 years; interquartile range (IQR), 20-23 years) and 27 health controls (median age, 21 years; IQR, 20-22 years) were prospectively included. Of the 77 participants, 32 had persistent cardiac symptoms and were not able to RTT at 3 months follow-up after experiencing EHS. The 2D global longitudinal strain (GLS) was significantly impaired in EHS participants compared to the healthy control group (-15.8 ± 1.7% vs -16.9 ± 1.2%, P = 0.001), which also showed significant statistical differences between participants with RTT and non-RTT (-15.0 ± 3.5% vs -16.5 ± 1.4%, P < 0.001). 2D-GLS (≤ -15.0%) (odds ratio, 1.53; 95% confidence interval: 1.08, 2.17; P = 0.016) was an independent predictor for RTT even after adjusting known risk factors. 2D-GLS provided incremental prognostic value over the clinical model and conventional CMR parameters model (AUCs: 0.72 vs 0.88, P = 0.013; 0.79 vs 0.88, P = 0.023; respectively).

CONCLUSION

Two-dimensional global longitudinal strain (≤ -15.0%) is an incremental prognostic CMR biomarker to predict RTT in soldiers suffering from EHS.

Heat-Related Illnesses

There is a growing incidence of heat-related illnesses due to rising global temperatures. Heat-related illnesses range from mild to severe, with heat stroke being the most critical. The wet bulb global temperature index considers humidity and solar intensity; its use is recommended to estimate heat stress on an individual and mitigate risk. Efficient cooling methods, such as cold water immersion, are essential in severe cases. Prevention is through hydration, appropriate clothing, recognition of high risk medications, and awareness of environmental conditions. Recognizing heat-related illnesses early in the clinical course and implementing rapid cooling strategies reduces morbidity and mortality.

Desert Medicine

Deserts are defined by their arid nature, characterized by little rainfall, and often featuring vast stretches of sandy terrain with sparse vegetation. The resulting variations in temperature, humidity, and topography predispose patients to medical conditions that practitioners in both rural and urban deserts must recognize and manage. This article will equip medical practitioners with the essential knowledge and tools to navigate these complexities, including a description of specific environmental considerations and challenges encountered while providing care in these desert locations, common conditions associated with extreme heat and solar radiation, and animal encounters.

The significant mechanism and treatments of cell death in heatstroke

With global warming, extreme environmental heat is becoming a social issue of concern, which can cause adverse health results including heatstroke (HS). Severe heat stress is characterized by cell death of direct heat damage, excessive inflammatory responses, and coagulation disorders that can lead to multiple organ dysfunction (MODS) and even death. However, the significant pathophysiological mechanism and treatment of HS are still not fully clear. Various modes of cell death, including apoptosis, pyroptosis, ferroptosis, necroptosis and PANoptosis are involved in MODS induced by heatstroke. In this review, we summarized molecular mechanism, key transcriptional regulation as for HSF1, NRF2, NF-κB and PARP-1, and potential therapies of cell death resulting in CNS, liver, intestine, reproductive system and kidney injury induced by heat stress. Understanding the mechanism of cell death provides new targets to protect multi-organ function in HS.

Proteomics Analysis of Proteotoxic Stress Response in In-Vitro Human Neuronal Models

Heat stroke, a hazardous hyperthermia-related illness, is characterized by CNS injury, particularly long-lasting brain damage. A root cause for hyperthermic neurological damage is heat-induced proteotoxic stress through protein aggregation, a known causative agent of neurological disorders. Stress magnitude and enduring persistence are highly correlated with hyperthermia-associated neurological damage. We used an untargeted proteomic approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify and characterize time-series proteome-wide changes in dose-responsive proteotoxic stress models in medulloblastoma [Daoy], neuroblastoma [SH-SY5Y], and differentiated SH-SY5Y neuron-like cells [SH(D)]. An integrated analysis of condition-time datasets identified global proteome-wide differentially expressed proteins (DEPs) as part of the heat-induced proteotoxic stress response. The condition-specific analysis detected higher DEPs and upregulated proteins in extreme heat stress with a relatively conservative and tight regulation in differentiated SH-SY5Y neuron-like cells. Functional network analysis using ingenuity pathway analysis (IPA) identified common intercellular pathways associated with the biological processes of protein, RNA, and amino acid metabolism and cellular response to stress and membrane trafficking. The condition-wise temporal pathway analysis in the differentiated neuron-like cells detects a significant pathway, functional, and disease association of DEPs with processes like protein folding and protein synthesis, Nervous System Development and Function, and Neurological Disease. An elaborate dose-dependent stress-specific and neuroprotective cellular signaling cascade is also significantly activated. Thus, our study provides a comprehensive map of the heat-induced proteotoxic stress response associating proteome-wide changes with altered biological processes. This helps to expand our understanding of the molecular basis of the heat-induced proteotoxic stress response with potential translational connotations.

Heat acclimation with probiotics-based ORS supplementation alleviates heat stroke-induced multiple organ dysfunction via improving intestinal thermotolerance and modulating gut microbiota in rats

Heat stroke (HS) is a critical condition with extremely high mortality. Heat acclimation (HA) is widely recognized as the best measure to prevent and protect against HS. Preventive administration of oral rehydration salts III (ORSIII) and probiotics have been reported to sustain intestinal function in cases of HS. This study established a rat model of HA that was treated with probiotics-based ORS (ORSP) during consecutive 21-day HA training. The results showed that HA with ORSP could attenuate HS-induced hyperthermia by regulating thermoregulatory response. We also found that HA with ORSP could significantly alleviate HS-induced multiple organ injuries. The expression levels of a series of heat-shock proteins (HSPs), including HSP90, HSP70, HSP60, and HSP40, were significantly up-regulated from the HA training. The increases in intestinal fatty acid binding protein (I-FABP) and D-Lactate typically seen during HS were decreased through HA. The representative TJ proteins including ZO-1, E-cadherin, and JAM-1 were found to be significantly down-regulated by HS, but sustained following HA. The ultrastructure of TJ was examined by TEM, which confirmed its protective effect on the intestinal barrier protection following HA. We also demonstrated that HA raised the intestinal levels of beneficial bacteria Lactobacillus and lowered those of the harmful bacteria Streptococcus through 16S rRNA gene sequencing. These findings suggest that HA with ORSP was proven to improve intestinal thermotolerance and the levels of protective gut microbiota against HS.

Prediction of in-hospital mortality in patients with exertional heatstroke: a 13-year retrospective study

Hyperactivity of coagulation is common in exertional heatstroke (EHS). Disseminated intravascular coagulation (DIC) is the most severe form of coagulation dysfunction and associated with poor outcome. DIC, temperature and Glasgow coma scale score were identified as independent risk factors for in-hospital mortality by multivariate logistic regression analysis, and we developed a nomogram for predicting in-hospital mortality in a 13-year EHS patient cohort. The nomogram was assessed by calibration curves and bootstrap with 1,000 resamples. The receiver operating characteristic curve was constructed, and the area under the curve (AUC) was compared. Two hundred and ten patients were included. The in-hospital mortality was 9.0%, and the incidence of DIC was 17.6%. The AUC of the nomogram was 0.897 (95% CI 0.848-0.935, p < .0001) and was non-inferior to SOFA and APACHE II scores but superior to SIRS score, which were widely-used score systems of disease severity. The nomogram contributed to the adverse outcome prediction of EHS.

Outcomes of UK military personnel treated with ice cold water immersion for exertional heat stroke

INTRODUCTION

Despite mitigation efforts, exertional heat stroke (EHS) is known to occur in military personnel during training and operations. It has significant potential to cause preventable morbidity and mortality. International consensus from sports medicine organisations supports treating EHS with early rapid cooling by immersing the casualty in cold water. However, evidence remains sparse and the practice is not yet widespread in the UK.

METHODS

Following changes to enable on-site ice cold water immersion (ICWI) at the Royal Marines Commando Training Centre, Lympstone, UK, we prospectively gathered data on 35 patients treated with ICWI over a 3-year period. These data included the incidence of adverse events (e.g. death, cardiac arrest or critical care admission) as the primary outcome. Basic anthropometric data, cooling rates achieved and biochemical and haematological test results on days 0-5 were also gathered and analysed.

RESULTS

Despite being a cohort of patients in whom we might expect significant morbidity and mortality based on the severity of EHS at presentation, none experienced a serious adverse event. In this cohort with rapid initiation of effective cooling, biochemical derangement appeared less severe than that reported in previous studies. Higher body mass index (BMI) was associated with a lower cooling rate across a range of values previously reported as potentially of clinical significance.

CONCLUSIONS

This case series supports recent updates to UK military guidance that ICWI should be more widely adopted for the treatment of EHS. Clinicians should be aware of likely patterns of blood test abnormalities in the days following EHS. Further work should seek to establish the impact of lower rates of cooling and develop strategies to optimise cooling in patients with higher BMI.

Dynamic molecular choreography induced by acute heat exposure in human males: a longitudinal multi-omics profiling study

Introduction

Extreme heat events caused by occupational exposure and heat waves are becoming more common. However, the molecular changes underlying the response to heat exposure in humans remain to be elucidated.

Methods

This study used longitudinal multi-omics profiling to assess the impact of acute heat exposure (50°C for 30 min) in 24 subjects from a mine rescue team. Intravenous blood samples were collected before acute heat exposure (baseline) and at 5 min, 30 min, 1 h, and 24 h after acute heat exposure (recovery). In-depth multi-omics profiling was performed on each sample, including plasma proteomics (untargeted) and metabolomics (untargeted).

Results

After data curation and annotation, the final dataset contained 2,473 analytes, including 478 proteins and 1995 metabolites. Time-series analysis unveiled an orchestrated molecular choreography of changes involving the immune response, coagulation, acid-base balance, oxidative stress, cytoskeleton, and energy metabolism. Further analysis through protein-protein interactions and network analysis revealed potential regulators of acute heat exposure. Moreover, novel blood-based analytes that predicted change in cardiopulmonary function after acute heat exposure were identified.

Conclusion

This study provided a comprehensive investigation of the dynamic molecular changes that underlie the complex physiological processes that occur in human males who undergo heat exposure. Our findings will help health impact assessment of extreme high temperature and inspire future mechanistic and clinical studies.

"Unravelling the impacts of climatic heat events on cardiovascular health in animal models"

Climate change has led to an increase in high ambient temperatures, causing extreme heat events worldwide. According to the World Meteorological Organization (WMO), July 2023 marked a historic milestone as the Earth reached its hottest recorded temperature, precisely hitting the critical threshold of 1.5 °C set by the Paris Agreement. This distressing development led to a stark warning from the United Nations, signaling the dawn of what they call "an era of global boiling". The increasing global temperatures can result in high heat stress which leads to various physiological and biochemical alterations in the human body. Given that cardiovascular diseases (CVDs) are a leading cause of morbidity and mortality globally, heat events exacerbate this public health issue. While clinical and in-vitro studies have suggested a range of pathophysiological and biochemical mechanisms underlying the body's response to heat stress, the complex nature of organ-system level interactions makes precise investigation challenging. To address this knowledge gap effectively, the use of animal models exposed to acute or chronic heat stress can be invaluable. These models can closely replicate the multifaceted effects observed in humans during heat stress conditions. Despite extensive independent reviews, limited focus has been shed on the high heat-induced cardiovascular complications and their mechanisms, particularly utilizing animal models. Therefore, in this comprehensive review, we highlight the crucial biomarkers altered during heat stress, contributing significantly to various CVDs. We explore potential mechanisms underlying heat-induced cardiovascular dysfunction and damage, delving into various animal models. While traditional rodent models are commonly employed, we also examine less conventional models, including ruminants, broilers, canines, and primates. Furthermore, we delve into various potential therapeutic approaches and preventive measures. These insights hold significant promise for the development of more effective clinical interventions against the effects of heat stress on the human cardiovascular system.

Risk factors for and outcomes of heatstroke-related intracerebral hemorrhage

Some patients with heatstroke also experience intracerebral hemorrhage (ICH). However, clinical case reports of heatstroke-induced ICH are rare. The risk factors for cerebral hemorrhage after heatstroke remain unknown. The present study evaluated the clinical characteristics and risk factors of patients with heatstroke-related ICH. In this retrospective observational study, we collected data on all ICHs after heatstroke occurred between 2012 and 2022. The characteristics of patients with heatstroke-induced ICH were described. The risk factors for cerebral hemorrhage after heatstroke were examined using logistic regression analysis. In total, 177 patients were included in this study, and 11 patients with ICH secondary to heatstroke were identified. Variables with P values of <.05 in univariate models, comparing the cerebral hemorrhage and control groups, included heatstroke cause, temperature, heart rate, respiratory rate, vasopressor use, mechanical ventilation use, Acute Physiology and Chronic Health Evaluation II, total bilirubin, creatinine, platelet count, prothrombin time, procalcitonin, creatine kinase, disseminated intravascular coagulation (DIC) occurrence, and DIC score. Multivariate logistic regression showed that heatstroke patients with higher DIC scores (odds ratio, 18.402, 95% confidence interval, 1.384-244.763, P = .027) and higher creatine kinase levels (odds ratio, 1.021, 95% confidence interval, 1.002-1.041, P = .033) were at a higher risk of developing ICH. The death rate was higher in the cerebral hemorrhage group than in the control group (P = .042). Heatstroke-related cerebral hemorrhage may be associated with elevated creatinine levels and DIC severity (International Society on Thrombosis and Hemostasis score) after heatstroke, and heatstroke with cerebral hemorrhage may accelerate death.

Heatstroke: a multicenter study in Southwestern China

Background

An increase in Heatstroke cases occurred in southwest China in 2022 due to factors like global warming, abnormal temperature rise, insufficient power supply, and other contributing factors. This resulted in a notable rise in Heatstroke patients experiencing varying degrees of organ dysfunction. This descriptive study aims to analyze the epidemiology and clinical outcomes of Heatstroke patients in the ICU, providing support for standardized diagnosis and treatment, ultimately enhancing the prognosis of Heatstroke.

Methods

A retrospective, multicenter, descriptive analysis was conducted on Heatstroke patients admitted to ICUs across 83 hospitals in southwest China. Electronic medical records were utilized for data collection, encompassing various aspects such as epidemiological factors, onset symptoms, complications, laboratory data, concurrent infections, treatments, and patient outcomes.

Results

The dataset primarily comprised classic heatstroke, with 477 males (55% of total). The patient population had a median age of 72 years (range: 63-80 years). The most common initial symptoms were fever, mental or behavioral abnormalities, and fainting. ICU treatment involved respiratory support, antibiotics, sedatives, and other interventions. Among the 700 ICU admissions, 213 patients had no infection, while 487 were diagnosed with infection, predominantly lower respiratory tract infection. Patients presenting with neurological symptoms initially (n = 715) exhibited higher ICU mortality risk compared to those without neurological symptoms (n = 104), with an odds ratio of 2.382 (95% CI 1.665, 4.870) (p = 0.017).

Conclusion

In 2022, the majority of Heatstroke patients in southwest China experienced classical Heatstroke, with many acquiring infections upon admission to the ICU. Moreover, Heatstroke can result in diverse complications.

Hyperbaric oxygen preconditioning normalizes scrotal temperature, sperm quality, testicular structure, and erectile function in adult male rats subjected to exertional heat injury

Testicular hyperthermia has been noted in men who work in high ambient temperatures. Scrotal temperatures above the normal range caused germ cell loss in the testes and resulted in male subfertility. In adult male rats, exercising at a higher environmental temperature (36 °C with relative humidity of 50%, 52 min) caused exertional heat stroke (EHS) characterized by scrotal hyperthermia, impaired sperm quality, dysmorphology in testes, prostates and bladders, and erectile dysfunction. Here, we aim to ascertain whether hyperbaric oxygen preconditioning (HBOP: 100% O2 at 2.0 atm absolute [ATA] for 2 h daily for 14 days consequently before the onset of EHS) is able to prevent the problem of EHS-induced sterility, testes, prostates, and bladders dysmorphology and erectile dysfunction. At the end of exertional heat stress compared to normobaric air (NBA or non-HBOP) rats, the HBOP rats exhibited lower body core temperature (40 °C vs. 43 °C), lower scrotal temperature (34 °C vs. 36 °C), lower neurological severity scores (2.8 vs. 5.8), higher erectile ability, (5984 mmHg-sec vs. 3788 mmHg-sec), higher plasma testosterone (6.8 ng/mL vs. 3.5 ng/mL), lower plasma follicle stimulating hormone (196.3 mIU/mL vs. 513.8 mIU/mL), lower plasma luteinizing hormone (131 IU/L vs. 189 IU/L), lower plasma adrenocorticotropic hormone (5136 pg/mL vs. 6129 pg/mL), lower plasma corticosterone (0.56 ng/mL vs. 1.18 ng/mL), lower sperm loss and lower values of histopathological scores for epididymis, testis, seminal vesicle, prostate, and bladder. Our data suggest that HBOP reduces body core and scrotal hyperthermia and improves sperm loss, testis/prostate/bladder dysmorphology, and erectile dysfunction after EHS in rats.

Monocyte HLA-DR level on admission predicting in-hospital mortality rate in exertional heatstroke: A 12-year retrospective study

BACKGROUND

Exertional heatstroke (EHS), a fatal illness, pronounces multiple organ dysfunction syndrome (MODS) and high mortality rate. Currently, no ideal factor prognoses EHS. Decreased monocyte human leukocyte-DR antigen (mHLA-DR) has been observed in critically ill individuals, particularly in those with sepsis. While most research focus on the pro-inflammatory response exploration in EHS, there are few studies related to immunosuppression, and no report targeted on mHLA-DR in EHS. The present study tried to explore the prognostic value of mHLA-DR levels in EHS patients.

METHODS

This was a single-center retrospective study. Clinical data of EHS patients admitted to the intensive care unit of the General Hospital of Southern Theatre Command between January 1, 2008, and December 31, 2020, were recorded and analyzed.

RESULTS

Seventy patients with 54 survivors and 16 nonsurvivors were ultimately enrolled. Levels of mHLA-DR in the nonsurvivors (41.8% [38.1-68.1]%) were significantly lower than those in the survivors (83.1% [67.6-89.4]%, p < 0.001). Multivariate logistic regression indicated that mHLA-DR (odds ratio [OR] = 0.939; 95% confidence interval [CI]: 0.892-0.988; p = 0.016) and Glasgow coma scale (GCS) scores (OR = 0.726; 95% CI: 0.591-0.892; p = 0.002) were independent risk factors related with in-hospital mortality rate in EHS. A nomogram incorporated mHLA-DR with GCS demonstrated excellent discrimination and calibration abilities. Compared to the traditional scoring systems, the prediction model incorporated mHLA-DR with GCS had the highest area under the curve (0.947, 95% CI: [0.865-0.986]) and Youden index (0.8333), with sensitivity of 100% and specificity of 83.33%, and a greater clinical net benefit.

CONCLUSION

Patients with EHS were at a risk of early experiencing decreased mHLA-DR early. A nomogram based on mHLA-DR with GCS was developed to facilitate early identification and timely treatment of individuals with potentially poor prognosis.

Lactate combined with SOFA score for improving the predictive efficacy of SOFA score in patients with severe heatstroke

BACKGROUND

The relationship between lactate levels and multiple organ dysfunction in patients with severe heatstroke remains unclear. In this study, we aimed to elucidate the clinical significance of lactate in severe heatstroke prognosis and assess whether incorporating lactate in the SOFA score improves its predictive efficacy.

METHODS

This study was a multicenter retrospective cohort investigation included 275 patients. Logistic regression analysis was performed to examine the relationship between lactate levels and patient outcomes and complications, including acute kidney injury (AKI), disseminated intravascular coagulation (DIC), and myocardial injury. Further, receiver operating characteristic (ROC) curves and clinical decision curve analysis (DCA) were used to evaluate the predictive power of lactate and SOFA scores in severe heatstroke-associated death. Lastly, the Kaplan-Meier survival curve was employed to differentiate the survival rates among the various patient groups.

RESULTS

After adjusting for confounding factors, lactate was demonstrated as an independent risk factor for death (OR = 1.353, 95% CI [1.170, 1.569]), AKI (OR = 1.158, 95% CI [1.007, 1.332]), DIC (OR = 1.426, 95% CI [1.225, 1.659]), and myocardial injury (OR = 2.039, 95% CI [1.553, 2.679]). The area under the curve (AUC) of lactate for predicting death from severe heatstroke was 0.7540, with a cutoff of 3.35. The Kaplan-Meier survival curve analysis showed that patients with elevated lactate levels had higher mortality rates. Additionally, the ROC curves demonstrated that combining lactate with the SOFA score provided better predictive efficacy than the SOFA score alone in patients with severe heatstroke (AUC: 0.9025 vs. 0.8773, DeLong test, P < 0.001). Finally, the DCA curve revealed a higher net clinical benefit rate for lactate combined with the SOFA score.

CONCLUSIONS

Lactate is an independent risk factor for severe heatstroke-related death as well as a risk factor for AKI, DIC, and myocardial injury associated with severe heatstroke. Thus, combining lactate with the SOFA score can significantly improve its predictive efficacy in patients with severe heatstroke.

Neurological patients confronting climate change: A potential role for the glymphatic system and sleep

Interest in the health consequences of climate change (global warming, heatwaves) has increased in the neurological community. This review addresses the impact of elevated ambient temperatures and heatwaves on patients with neurological and mental health disorders, including multiple sclerosis, synucleinopathies, dementia, epilepsies, mental health, and stroke. Patients with such conditions are highly vulnerable during heatwaves because of functional disorders affecting sleep, thermoregulation, autonomic system reactivity, mood, and cognitive ability. Several medications may also increase the risk of heatstroke. Special attention is devoted to the involvement of common underlying mechanisms, such as sleep and the glymphatic system. Disease prevention and patient care during heatwaves are major issues for caregivers. Beyond the usual recommendations for individuals, we favor artificially induced acclimation to heat, which provides preventive benefits with proven efficacy for healthy adults.

Exploring the Potential of CarbonCool® in Rapid Prehospital Cooling for Severe Heat Stroke

OBJECTIVE

Heat stroke is a life-threatening condition that is characterized by body temperatures above 40 °C and central nervous system dysfunction. Immediate cooling is imperative to prevent irreversible cellular damage and improve patient outcomes. Here, we report two cases of heat stroke that highlight the use of a novel cooling suit (CarbonCool®) as a rapid cooling intervention administered in the prehospital setting, primarily focusing on patients with classic heat stroke.

METHODS

This study was a retrospective review of two cases involving older patients with severe classic heat stroke, wherein CarbonCool® was used. The device was deployed at the scene of the incidents, throughout transport, and into the emergency department setting, allowing for continuous cooling and medical intervention as needed. The effectiveness of the cooling device was assessed based on the rate of temperature reduction and overall clinical outcomes of the patients.

RESULTS

In both cases, CarbonCool® facilitated a rapid reduction in body temperature, aligning with the crucial requirement of immediate cooling for the management of heat stroke. The first case involved a comatose 90-year-old woman whose body temperature decreased from 42.0 to 35.8 °C within 60 min. The second case involved a comatose 70-year-old man who experienced a decrease in body temperature from 41.2 to 36.6 °C over 196 min. CarbonCool® allowed for the execution of concurrent resuscitative procedures and was compatible with various imaging modalities (including computed tomographic scan), allowing for continuous application from the scene to the intensive care unit. Moreover, both patients showed marked improvements in consciousness and were stabilized without the need for more invasive cooling procedures that are typically employed in hospital settings for such cases. Both patients were discharged without any disabilities.

CONCLUSION

We present an innovative approach to prehospital care for patients with heat stroke through the use of CarbonCool®, highlighting its efficacy for rapid cooling and its potential impact on patient outcomes. However, further studies are warranted to fully confirm the efficacy of the system.

Risk factors for brain injury in patients with exertional heatstroke: A 5-year experience

PURPOSE

Minimal data exist on brain injury in patients with exertional heatstroke (EHS) in developing country. In this study, we explored the risk factors for brain injury induced by EHS 90-day after onset.

METHODS

A retrospective cohort study of patients with EHS was conducted in the intensive care unit of the General Hospital of Southern Theater Command of PLA in China from April 2014 to June 2019. Patients were divided into non-brain injury (fully recovered) and brain injury groups (comprising deceased patients or those with neurological sequelae). The brain injury group was further subdivided into a death group and a sequela group for detailed analysis. General information, neurological performance and information on important organ injuries in the acute stage were recorded and analysed. Multivariable logistic regression was used to identify risk factors for brain injury after EHS and mortality risk factors for brain injury, and Kaplan-Meier survival curve was used to evaluate the effect of the neurological dysfunction on survival.

RESULTS

Out of the 147 EHS patients, 117 were enrolled, of which 96 (82.1%) recovered, 13 (11.1%) died, and 8 (6.8%) experienced neurological sequelae. Statistically significant differences were found between non-brain injury and brain injury groups in age, hypotension, duration of consciousness disorders, time to drop core body temperature below 38.5°C, lymphocyte counts, platelet counts, procalcitonin, alanine aminotransferase, aspartate aminotransferase, creatinine, cystatin C, coagulation parameters, international normalized ratio, acute physiology and chronic health evaluation II scores, sequential organ failure assessment (SOFA) scores, and Glasgow coma scale scores (all p < 0.05). Multivariate logistic regression showed that age (OR = 1.090, 95% CI: 1.02 - 1.17, p = 0.008), time to drop core temperature (OR = 8.223, 95% CI: 2.30 - 29.40, p = 0.001), and SOFA scores (OR = 1.676, 95% CI: 1.29 - 2.18, p < 0.001) are independent risk factors for brain injury induced by EHS. The Kaplan-Meier curves suggest significantly prolonged survival (p < 0.001) in patients with early Glasgow coma scale score > 8 and duration of consciousness disorders ≤ 24 h.

CONCLUSIONS

Advanced age, delayed cooling, and higher SOFA scores significantly increase the risk of brain injury post-EHS. These findings underscore the importance of rapid cooling and early assessment of organ failure to improve outcomes in EHS patients.

Management of Heat-Related Illness and Injury in the ICU: A Concise Definitive Review

OBJECTIVES

The increasing frequency of extreme heat events has led to a growing number of heat-related injuries and illnesses in ICUs. The objective of this review was to summarize and critically appraise evidence for the management of heat-related illnesses and injuries for critical care multiprofessionals.

DATA SOURCES

Ovid Medline, Embase, Cochrane Clinical Trials Register, Cumulative Index to Nursing and Allied Health Literature, and ClinicalTrials.gov databases were searched from inception through August 2023 for studies reporting on heat-related injury and illness in the setting of the ICU.

STUDY SELECTION

English-language systematic reviews, narrative reviews, meta-analyses, randomized clinical trials, and observational studies were prioritized for review. Bibliographies from retrieved articles were scanned for articles that may have been missed.

DATA EXTRACTION

Data regarding study methodology, patient population, management strategy, and clinical outcomes were qualitatively assessed.

DATA SYNTHESIS

Several risk factors and prognostic indicators for patients diagnosed with heat-related illness and injury have been identified and reported in the literature. Effective management of these patients has included various cooling methods and fluid replenishment. Drug therapy is not effective. Multiple organ dysfunction, neurologic injury, and disseminated intravascular coagulation are common complications of heat stroke and must be managed accordingly. Burn injury from contact with hot surfaces or pavement can occur, requiring careful evaluation and possible excision and grafting in severe cases.

CONCLUSIONS

The prevalence of heat-related illness and injury is increasing, and rapid initiation of appropriate therapies is necessary to optimize outcomes. Additional research is needed to identify effective methods and strategies to achieve rapid cooling, the role of immunomodulators and anticoagulant medications, the use of biomarkers to identify organ failure, and the role of artificial intelligence and precision medicine.

l-Carnitine pretreatment ameliorates heat stress-induced acute kidney injury by restoring mitochondrial function of tubular cells

A major complication of heat-related illness is the development of acute kidney injury (AKI) and damage to kidney tubular cells. Because kidney tubular cells use fatty acids as a major energy source, impaired fatty acid oxidation (FAO) may be associated with kidney injury due to heat stress. Carnitine is essential in the transportation of fatty acid into mitochondria for FAO. To date, there has been little attention given to the role of carnitine in heat-related illness and AKI. To evaluate the relationship between carnitine inadequacy and heat-related illness severity or AKI, we examined serum carnitine levels in patients with heat-related illness. We also used heat-stressed mice to investigate the effect of l-carnitine pretreatment on various kidney functions such as mitochondrial activity, proinflammatory changes in kidney macrophages, and histological damage. We observed an elevation in serum acylcarnitine levels, indicating carnitine insufficiency in patients with severe heat-related illness and/or AKI. l-Carnitine pretreatment ameliorated ATP production in murine tubular cell mitochondria and prevented a change in the kidney macrophage population dynamics observed in AKI: a decrease in tissue-resident macrophages, influx of bone marrow-derived macrophages, and change toward proinflammatory M1 polarization. In conclusion, carnitine insufficiency may be closely associated with severe heat-related illness and related AKI. Enhancement of the FAO pathway by l-carnitine pretreatment may prevent heat stress-induced AKI by restoring mitochondrial function.NEW & NOTEWORTHY Enhancing fatty acid oxidation (FAO) after acute kidney injury (AKI) improves renal outcomes. This report shows that carnitine insufficiency, which could inhibit FAO, correlates to severe heat-related illness and AKI in a clinical study. We also demonstrate that administering l-carnitine to mice improves mitochondrial respiratory function and prevents deleterious changes in renal macrophage, resulting in improved renal outcomes of heat-induced AKI. l-Carnitine may be an effective preventive treatment for severe heat-related illness and related AKI.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.

Hygrothermal stress increases malignant arrhythmias susceptibility by inhibiting the LKB1-AMPK-Cx43 pathway

High mortality due to hygrothermal stress during heat waves is mostly linked to cardiovascular malfunction, the most serious of which are malignant arrhythmias. However, the mechanism associated with hygrothermal stress leading to malignant arrhythmias remains unclear. The energy metabolism regulated by liver kinase B1 (LKB1) and adenosine monophosphate-activated protein kinase (AMPK) and the electrical signaling based on gap junction protein, connexin43 (Cx43), plays important roles in the development of cardiac arrhythmias. In order to investigate whether hygrothermal stress induces arrhythmias via the LKB1-AMPK-Cx43 pathway, Sprague-Dawley rats were exposed to high temperature and humidity for constructing the hygrothermal stress model. A final choice of 40 °C and 85% humidity was made by pre-exploration based on different gradient environmental conditions with reference to arrhythmia event-inducing stability and risk of sudden death. Then, the incidence of arrhythmic events, as well as the expression, phosphorylation at Ser368, and distribution of Cx43 in the myocardium, were examined. Meanwhile, the adenosine monophosphate-activated protein kinase activator, Acadesine, was also administered to investigate the role played by AMPK in the process. Our results showed that hygrothermal stress induced malignant arrhythmias such as ventricular tachycardia, ventricular fibrillation, and severe atrioventricular block. Besides, hygrothermal stress decreased the phosphorylation of Cx43 at Ser368, induced proarrhythmic redistribution of Cx43 from polar to lateral sides of the cardiomyocytes, and also caused LKB1 and phosphorylated-AMPK expression to be less abundant. While, pretreatment with Acadesine significantly actived the LKB1-AMPK-Cx43 pathway and thus ameliorated malignant arrhythmias, indicating that the hygrothermal stress-induced arrhythmias is associated with the redistribution of gap junctions in cardiomyocytes and the organism's energy metabolism.

The relationship between climate change, globalization and non-communicable diseases in Africa: A systematic review

Climate change and non-communicable diseases (NCDs) are considered the 21st Century's major health and development challenges. Both pose a disproportionate burden on low- and middle-income countries that are unprepared to cope with their synergistic effects. These two challenges pose risks for achieving many of the sustainable development goals (SDGs) and are both impacted by globalization through different pathways. While there are important insights on how climate change and or globalization impact NCDs in the general literature, comprehensive research that explores the influence of climate change and or globalization on NCDs is limited, particularly in the context of Africa. This review documents the pathways through which climate change and or globalization influence NCDs in Africa. We conducted a comprehensive literature search in eight electronic databases-Web of Science, PubMed, Scopus, Global Health Library, Science Direct, Medline, ProQuest, and Google Scholar. A total of 13864 studies were identified. Studies that were identified from more than one of the databases were automatically removed as duplicates (n = 9649). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a total of 27 studies were eventually included in the final review. We found that the impacts of climate change and or globalization on NCDs act through three potential pathways: reduction in food production and nutrition, urbanization and transformation of food systems. Our review contributes to the existing literature by providing insights into the impact of climate change and or globalization on human health. We believe that our findings will help enlighten policy makers working on these pathways to facilitate the development of effective policy and public health interventions to mitigate the effects of climate change and globalization on the rising burden of NCDs and goal 3 of the SDG, in particular.

Case report and literature review: Acute rhabdomyolysis caused by overheating of electric blanket complicated with Guillain-Barré syndrome

Rhabdomyolysis (RM) induced by electric blankets is exceedingly rare, with only three cases identified in our literature review. Both RM and Guillain-Barré syndrome (GBS) present with similar clinical manifestations of myalgia and muscle weakness, posing a potential challenge for accurate diagnosis in clinical settings. This report presents the case of a 22-year-old man who developed RM subsequent to the use of an electric blanket. Despite undergoing plasma exchange and renal replacement therapy, the patient continued to exhibit poor muscle strength in both lower limbs. Subsequent comprehensive evaluation revealed the presence of concurrent GBS. Following a 5-day course of intravenous gamma globulin treatment, the patient experienced rapid recovery of muscle strength and was discharged. Additionally, we reviewed seven cases from the literature of coexistent RM and GBS. This indicated that investigation of the timing of onset of muscle strength decline in RM patients could help to identify potential concurrent neurological or muscular disorders. In cases in which concurrent GBS and RM cannot be definitively ascertained during early hospitalization, prioritizing plasma exchange treatment may lead to improved patient outcomes.

Multimodal imaging shows acute multilayered retinal hemorrhages in heatstroke-a rare case report

Background

Heatstroke is a life-threatening disease clinically characterized by central nervous system dysfunction, multiorgan failure, and extreme hyperthermia. There are no reports about eye involvement in heat stroke. Here, we report a rare case of multilayered retinal hemorrhages in a patient with heatstroke.

Case presentation

A 55-year-old male with a one-month history of blurry vision in both eyes presented at our department after suffering from heatstroke. His visual acuity was 5/20 OD and 10/20 OS. Fundus examination revealed retinal hemorrhages in both eyes. Fundus autofluorescence images and near-infrared reflectance images revealed well-defined retinal lesions. Optical coherence tomography helped to accurately locate the different layers of the lesions, including the nerve fiber layer, sub-inner limiting membrane, outer plexiform layer, ellipsoid zone and Henle fiber layer hemorrhages. We followed up with the patient for 8 months. At the last follow-up, his visual acuity was 20/20 in both eyes, and fundus examination showed that retinal hemorrhages were almost completely absorbed.

Conclusion

To our knowledge, this is the first report on multilayered retinal hemorrhages secondary to heat stroke. Intraretinal and preretinal hemorrhages can gradually resolve, and the patient's vision will improve with the absorption of the retinal hemorrhages. Multimodal imaging may help to reveal additional details about retinal lesions and monitor the course of the disease.

Heatstroke presentations to urban hospitals during BC's extreme heat event: lessons for the future

BACKGROUND

Climate change is leading to more extreme heat events in temperate climates that typically have low levels of preparedness. Our objective was to describe the characteristics, treatments, and outcomes of adults presenting to hospitals with heatstroke during BC's 2021 heat dome.

METHODS

We conducted a review of consecutive adults presenting to 7 hospitals in BC's Lower Mainland. We screened the triage records of all patients presenting between June 25th and 30th, 2021 for complaints related to heat, and reviewed the full records of those who met heatstroke criteria. Our primary outcome was in-hospital mortality. We used Mann-Whitney U tests and logistic regression to investigate associations between patient and treatment factors and mortality.

RESULTS

Among 10,247 consecutive presentations to urban hospitals during the extreme heat event, 1.3% (139; 95% confidence intervals [CI] 1.1-1.6%) met criteria for heatstroke. Of heatstroke patients, 129 (90.6%) were triaged into the two highest acuity levels. Patients with heatstroke had a median age of 84.4 years, with 122 (87.8%) living alone, and 101 (84.2%) unable to activate 911 themselves. A minority (< 5, < 3.6%) of patients presented within 48 h of the onset of extreme heat. Most patients (107, 77.0%) required admission, and 11.5% (16) died in hospital. Hypotension on presentation was associated with mortality (odds ratio [OR] 5.3).

INTERPRETATION

Heatstroke patients were unable to activate 911 themselves, and most presented with a 48-h delay. This delay may represent a critical window of opportunity for pre-hospital and hospital systems to prepare for the influx of high-acuity resource-intensive patients.

The Impact of Climate Change and Extreme Weather Conditions on Cardiovascular Health and Acute Cardiovascular Diseases

Climate change is widely recognized as one of the most significant challenges facing our planet and human civilization. Human activities such as the burning of fossil fuels, deforestation, and industrial processes release greenhouse gases into the atmosphere, leading to a warming of the Earth's climate. The relationship between climate change and cardiovascular (CV) health, mediated by air pollution and increased ambient temperatures, is complex and very heterogeneous. The main mechanisms underlying the pathogenesis of CV disease at extreme temperatures involve several regulatory pathways, including temperature-sympathetic reactivity, the cold-activated renin-angiotensin system, dehydration, extreme temperature-induced electrolyte imbalances, and heat stroke-induced systemic inflammatory responses. The interplay of these mechanisms may vary based on individual factors, environmental conditions, and an overall health background. The net outcome is a significant increase in CV mortality and a higher incidence of hypertension, type II diabetes mellitus, acute myocardial infarction (AMI), heart failure, and cardiac arrhythmias. Patients with pre-existing CV disorders may be more vulnerable to the effects of global warming and extreme temperatures. There is an urgent need for a comprehensive intervention that spans from the individual level to a systemic or global approach to effectively address this existential problem. Future programs aimed at reducing CV and environmental burdens should require cross-disciplinary collaboration involving physicians, researchers, public health workers, political scientists, legislators, and national leaders to mitigate the effects of climate change.

Gastrointestinal manifestations of critical ill heatstroke patients and their associations with outcomes: A multicentre, retrospective, observational study

BACKGROUND

Extreme heat exposure is a growing health problem, and the effects of heat on the gastrointestinal (GI) tract is unknown. This study aimed to assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes.

AIM

To assess the incidence of GI symptoms associated with heatstroke and its impact on outcomes.

METHODS

Patients admitted to the intensive care unit (ICU) due to heatstroke were included from 83 centres. Patient history, laboratory results, and clinically relevant outcomes were recorded at ICU admission and daily until up to day 15, ICU discharge, or death. GI symptoms, including nausea/vomiting, diarrhoea, flatulence, and bloody stools, were recorded. The characteristics of patients with heatstroke concomitant with GI symptoms were described. Multivariable regression analyses were performed to determine significant predictors of GI symptoms.

RESULTS

A total of 713 patients were included in the final analysis, of whom 132 (18.5%) patients had at least one GI symptom during their ICU stay, while 26 (3.6%) suffered from more than one symptom. Patients with GI symptoms had a significantly higher ICU stay compared with those without. The mortality of patients who had two or more GI symptoms simultaneously was significantly higher than that in those with one GI symptom. Multivariable logistic regression analysis revealed that older patients with a lower GCS score on admission were more likely to experience GI symptoms.

CONCLUSION

The GI manifestations of heatstroke are common and appear to impact clinically relevant hospitalization outcomes.

Idiopathic segmental anhidrosis in an older patient presenting with recurrent dizziness

Dizziness is one of the most common complaints encountered in the outpatient clinic, which is difficult to diagnose, especially in older patients because of the multifactorial nature of the disease. Although not commonly recognised, anhidrosis can also cause dizziness.We report a case of a woman in her 70s who presented with long-term recurrent dizziness. She had a history of frequent hospitalisations for heatstroke. Physical examination revealed markedly less sweating in the left axilla and soles than in the right. Minol test revealed that most of the left side of her body, including the face, was anhidrotic. She was diagnosed with idiopathic segmental anhidrosis. We administered steroid pulse therapy without observing any significant effects.Although anhidrosis is a rare disorder, a careful interview and physical examination should be conducted to confirm a history of heatstroke and the absence of sweating to avoid missing the disease.

The pathogenesis and therapeutic strategies of heat stroke-induced myocardial injury

Heat stroke (HS) is a febrile illness characterized by an elevation in the core body temperature to over 40°C, accompanied by central nervous system impairment and subsequent multi-organ dysfunction syndrome. In recent years, the mortality rate from HS has been increasing as ambient temperatures continue to rise each year. The cardiovascular system plays an important role in the pathogenesis process of HS, as it functions as one of the key system for thermoregulation and its stability is associated with the severity of HS. Systemic inflammatory response and endothelial cell damage constitute pivotal attributes of HS, other factors such as ferroptosis, disturbances in myocardial metabolism and heat shock protein dysregulation are also involved in the damage to myocardial tissue in HS. In this review, a comprehensively detailed description of the pathogenesis of HS-induced myocardial injury is provided. The current treatment strategies and the promising therapeutic targets for HS are also discussed.

Amide proton transfer imaging in rats after heatstroke

Metabolic acidosis is the most common acid-base change following heatstroke. This study aimed to evaluate the internal environment changes caused by heatstroke using amide proton transfer (APT) imaging. Nineteen male Sprague-Dawley rats were randomly divided into the control group (CTRL, n  = 7) and the heatstroke group (HS, n  = 12). All the rats underwent a 7.0-T MRI, which included T2-weighted imaging (T2WI) and APT imaging. Subsequently, the surviving HS group rats repeated the same magnetic resonance scanning after 25 days and were designated as the follow-up group (FU, n  = 7). APT values were measured in the hippocampus, thalamus, and corpus callosum. The APT values of the three groups were statistically analyzed and found in the hippocampus (CTRL vs. HS, P  = 0.011; CTRL vs. FU, P  = 0.078; HS vs. FU, P  = 0.484; η ² = 0.276), left thalamus (CTRL vs. HS, P  = 0.004; CTRL vs. FU, P  = 0.014; HS vs. FU, P  = 0.822; η ² = 0.331), right thalamus (CTRL vs. HS, P  = 0.003; CTRL vs. FU, P  = 0.015; HS vs. FU P  = 0.769; η ² = 0.336), and corpus callosum (CTRL vs. HS, P  < 0.001; CTRL vs. FU, P  = 0.005; HS vs. FU, P  = 0.523; η ² = 0.437). APT imaging can be a viable and practical tool for diagnosing heatstroke and monitoring its progression.

Molecular and immunological origins of catatonia

Catatonia occurs secondary to both primary psychiatric and neuromedical etiologies. Emerging evidence suggests possible linkages between causes of catatonia and neuroinflammation. These include obvious infectious and inflammatory etiologies, common neuromedical illnesses such as delirium, and psychiatric entities such as depression and autism-spectrum disorders. Symptoms of sickness behavior, thought to be a downstream effect of the cytokine response, are common in many of these etiologies and overlap significantly with symptoms of catatonia. Furthermore, there are syndromes that overlap with catatonia that some would consider variants, including neuroleptic malignant syndrome (NMS) and akinetic mutism, which may also have neuroinflammatory underpinnings. Low serum iron, a common finding in NMS and malignant catatonia, may be caused by the acute phase response. Cellular hits involving either pathogen-associated molecular patterns (PAMP) danger signals or the damage-associated molecular patterns (DAMP) danger signals of severe psychosocial stress may set the stage for a common pathway immunoactivation state that could lower the threshold for a catatonic state in susceptible individuals. Immunoactivation leading to dysfunction in the anterior cingulate cortex (ACC)/mid-cingulate cortex (MCC)/medial prefrontal cortex (mPFC)/paralimbic cortico-striato-thalamo-cortical (CSTC) circuit, involved in motivation and movement, may be particularly important in generating the motor and behavioral symptoms of catatonia.