BACKGROUND: Exertional heat stroke (EHS), which presents with extreme hyperthermia and alteration to the central nervous system, disproportionately affects the military, where warfighters are expected to perform in all types of environmental conditions. Because of an incomplete understanding of individualized recovery from EHS, there are several shortcomings with the current guidance on return to duty (RTD) following an EHS. The purpose of this manuscript is to provide an updated literature review of best practices for return to duty following EHS to guide decision making regarding EHS and explore areas of future research for medical staff who work with warfighters.
METHODS: A literature review related to EHS in both athlete and military populations, as well as any existing guidelines for RTD, was conducted using PubMed and Covidence.
RESULTS: Twenty-one articles were identified for this updated review on EHS and RTD, with recommendations focused during and after an EHS event, as well as the role of heat tolerance testing (HTT).
CONCLUSIONS: EHS has a high morbidity and mortality rate if not treated rapidly. Because the extent of end-organ damage is dependent on the amount of time that the individual is hyperthermic, rapid diagnosis via rectal thermometry, and efficient cooling methods are imperative to the wellbeing of EHS patients. Following EHS, gradual RTD recommendations within the limits of operational demand should be implemented to reduce the risk for a subsequent heat injury event. While many versions of HTT, most notably the Israeli Defense Force (IDF) protocol, have been created to guide RTD recommendations, a universal assessment for heat tolerance has yet to be adopted. As such, medical personnel should apply a multifactorial approach to ensure safe RTD.

UNASSIGNED: Heatstroke (HS) is a severe form of heat-related illness (HRI) associated with high morbidity and mortality, representing a condition that includes long-term multiorgan dysfunction and susceptibility to further heat illness.
UNASSIGNED: In a systematic review searching Medline PubMed from the studies conducted between 2009 and 2020, 16 papers were identified.
UNASSIGNED: A hallmark symptom of heat stroke is CNS dysfunction (a hallmark sign of HS) which manifests as mental status changes, including agitation, delirium, epilepsy, or coma at the time of the collapse. Acute kidney injury (AKI), gut ischemia, blood clots in the stomach and small intestine, cytoplasmic protein clumps in the spleen, and injury of skeletal muscle (rhabdomyolysis) are all characteristics of peripheral tissue damage. Severe heat stroke tends to be complicated by rhabdomyolysis, especially in patients with exertional heat stroke. Rhabdomyolysis may lead to systemic effects, including the local occurrence of compartment syndrome, hyperkalemic cardiac arrest, and/or lethal disseminated intravascular coagulopathy. Untreated heat stroke might exacerbate psychosis, lactic acidosis, consumptive coagulopathy, hematuria, pulmonary edema, renal failure, and other metabolic abnormalities. Core body temperature and level of consciousness are the most significant indicators to diagnose the severity of heat stroke and prevent unfavorable consequences. Heatstroke is a life-threatening illness if not promptly recognized and effectively treated.
UNASSIGNED: This review highlighted that core body temperature and white blood cell count are significant contributing factors affecting heat stroke outcomes. Other factors contributing to the poor outcome include old age, low GCS, and prolonged hospital stay. The prevalence of both classic and exertional heatstroke can be reduced by certain simple preventive measures, such as avoiding strenuous activity in hot environments and reducing exposure to heat stress.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a syndrome with potentially fatal consequences that results from an excessive immune response caused by malfunctioning natural killer cells and cytotoxic T lymphocytes. Secondary HLH, which is the predominant type in adults, is associated with various medical conditions, including infections, malignancies, and autoimmune diseases. Secondary HLH associated with heat stroke has not been reported.
METHODS: A 74-year-old male was admitted to the emergency department after being unconscious in a 42°C hot public bath. The patient was witnessed to be in the water for more than 4 hours. The patient\'s condition was complicated by rhabdomyolysis and septic shock, which were managed with mechanical ventilation, vasoactive agents, and continuous renal replacement therapy. The patient also showed evidence of diffuse cerebral dysfunction.
METHODS: While the patient\'s condition initially improved, the patient developed a fever, anemia, thrombocytopenia, and an acute rise in total bilirubin, which, we suspected, was caused by HLH. Further investigations revealed elevated serum ferritin and soluble interleukin-2 receptor levels.
METHODS: The patient received 2 cycles of serial therapeutic plasma exchange to lower the endotoxin burden. To manage HLH, high-dose glucocorticoid therapy was done.
RESULTS: Despite the best efforts, the patient did not recover and expired from progressive hepatic failure.
CONCLUSIONS: We report a novel case of secondary HLH associated with heat stroke. Diagnosing secondary HLH can be difficult since clinical manifestations of the underlying disease and HLH may present simultaneously. Early diagnosis and prompt initiation of treatment is required to improve the prognosis of the disease.

This report highlights the feasibility of electrical cardioversion intervention for the treatment of heat stroke complicated by rapid atrial fibrillation. There has never been any mentions in the previous literature of the possibility of electrical cardioversion in the event of heat stroke complicated by rapid arrhythmia. A 61-year-old man with classic heat stroke complicated by rapid atrial fibrillation was admitted to our emergency department. In the early stages of treatment, hemodynamics were not stable under the treatments of aggressive cooling and volume-expanding rehydration. It was considered to be related to rapid atrial fibrillation, and the administration of drug cardiover and control of ventricular rate failed. Subsequently, synchronous electrical cardioversion was given 3 times (biphasic wave, energy: 70J-80J-100J, respectively), successfully cardioversion and hemodynamically stable. Although the patient eventually died of progressive deterioration of multiple organ failure, timely cardioversion might be effective for the treatment of heat stroke complicated by rapid atrial fibrillation.

Although classic heat stroke (HS) is one of the most ancient conditions known to humans, the description of its early clinical manifestations, natural course, and complications remains uncertain.
A systematic review of the demographics, clinical characteristics, biomarkers, therapy, and outcomes of HS during the Muslim (Hajj) pilgrimage in the desert climate of Mecca, Saudi Arabia.
We searched the MEDLINE, Embase, Web of Science Core Collection, SCOPUS, and CINAHL databases from inception to April 2022. We summarized the data from eligible studies and synthesized them in narrative form using pooled descriptive statistics.
Forty-four studies, including 2632 patients with HS, met the inclusion criteria. Overweight or obesity, diabetes, and cardiovascular disease were prevalent among cases of HS. Evidence suggests that extreme hyperthermia (pooled mean = 42.0°C [95% confidence interval (CI): 41.9, 42.1], range 40-44.8°C) with hot and dry skin (>99% of cases) and severe loss of consciousness (mean Glasgow Coma Scale <8 in 53.8% of cases) were the dominant clinical characteristics of classic HS. Hypotension, tachypnea, vomiting, diarrhea, and biochemical biomarkers indicating mild-to-moderate rhabdomyolysis, acute kidney, liver, heart injury, and coagulopathy were frequent at the onset. Concomitantly, stress hormones (cortisol and catecholamines) and biomarkers of systemic inflammation and coagulation activation were increased. HS was fatal in 1 in 18 cases (pooled case fatality rate = 5.6% [95%CI: 4.6, 6.5]).
The findings of this review suggest that HS induces an early multiorgan injury that can progress rapidly to organ failure, culminating in death, if it is not recognized and treated promptly.

Heat-related illnesses, which range from heat exhaustion to heatstroke, affect thousands of individuals worldwide every year and are characterized by extreme hyperthermia with the core body temperature (CBT) usually > 40 °C, decline in physical and athletic performance, CNS dysfunction, and, eventually, multiorgan failure. The measurement of CBT has been shown to predict heat-related illness and its severity, but the current measurement methods are not practical for use in high acuity and high motion settings due to their invasive and obstructive nature or excessive costs. Noninvasive predictions of CBT using wearable technology and predictive algorithms offer the potential for continuous CBT monitoring and early intervention to prevent HRI in athletic, military, and intense work environments. Thus far, there has been a lack of peer-reviewed literature assessing the efficacy of wearable devices and predictive analytics to predict CBT to mitigate heat-related illness. This systematic review identified 20 studies representing a total of 25 distinct algorithms to predict the core body temperature using wearable technology. While a high accuracy in prediction was noted, with 17 out of 18 algorithms meeting the clinical validity standards. few algorithms incorporated individual and environmental data into their core body temperature prediction algorithms, despite the known impact of individual health and situational and environmental factors on CBT. Robust machine learning methods offer the ability to develop more accurate, reliable, and personalized CBT prediction algorithms using wearable devices by including additional data on user characteristics, workout intensity, and the surrounding environment. The integration and interoperability of CBT prediction algorithms with existing heat-related illness prevention and treatment tools, including heat indices such as the WBGT, athlete management systems, and electronic medical records, will further prevent HRI and increase the availability and speed of data access during critical heat events, improving the clinical decision-making process for athletic trainers and physicians, sports scientists, employers, and military officers.

Humans maintain core body temperature via a complicated system of physiologic mechanisms that counteract heat/cold fluctuations from metabolism, exertion, and the environment. Overextension of these mechanisms or disruption of body temperature homeostasis leads to bodily dysfunction, culminating in a syndrome analogous to exertional heat stroke (EHS). The inability of this thermoregulatory process to maintain the body temperature is caused by either thermal stress or certain drugs. EHS is a syndrome characterized by hyperthermia and the activation of systemic inflammation. Several drug-induced hyperthermic syndromes may resemble EHS and share common mechanisms. The purpose of this article is to review the current literature and compare exertional heat stroke (EHS) to three of the most widely studied drug-induced hyperthermic syndromes: malignant hyperthermia (MH), neuroleptic malignant syndrome (NMS), and serotonin syndrome (SS). Drugs and drug classes that have been implicated in these conditions include amphetamines, diuretics, cocaine, antipsychotics, metoclopramide, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and many more. Observations suggest that severe or fulminant cases of drug-induced hyperthermia may evolve into an inflammatory syndrome best described as heat stroke. Their underlying mechanisms, symptoms, and treatment approaches will be reviewed to assist in accurate diagnosis, which will impact the management of potentially life-threatening complications.

UNASSIGNED: Heat stroke is a potentially fatal condition that is caused by elevated core temperature. Guillain-Barré syndrome (GBS) induced by heat stroke is extremely rare and has only been reported in few case reports. The purpose of this case study was to evaluate the clinical symptoms, neuroelectrophysiological and imageological features of GBS after heat stroke.
UNASSIGNED: We reviewed our hospital records and previously published reports to find the cases of GBS after heat stroke. The clinical, imageological, and electrophysiological profiles, treatment and prognosis were presented and analyzed.
UNASSIGNED: We retrieved three cases of GBS induced by heat stroke from our hospital, which presented as lesions on multiple cranial and peripheral nerves and albuminocytologic dissociation in the cerebrospinal fluid. All of these patients had disorders of consciousness at the early stage of heat stroke and a \"pseudo-recovery period\" after they recovered from coma after heat stroke. After immunoglobulin administration and immunoregulation therapy, these patients\' neurological deficiencies were relieved significantly. But there are still disabilities and almost totally reliant on others.
UNASSIGNED: The number of the cases of GBS induced by HS reported in this study has been the most in the recent 5 years. Clinicians should pay attention to patients with heat stroke with sustained coma and the sudden quadriplegia. Early, exact and timely diagnosis and treatment of GBS need to be performed, to accelerate recovery and improve prognosis.

BACKGROUND: Athletes with spinal cord injury (SCI) have difficulties in maintaining thermal homeostasis during exercise due to their lower sweat capacity and skin vasodilation. Skin temperature (Tsk) assessment, as opposed to core temperature, has become more widely accepted due to its non-invasive nature. The aims of this systematic review was to collate research studies that measured Tsk of individuals with SCI during or after exercise, study their Tsk response, taking into account the method employed, the environmental and exercise conditions, and to identify the different cooling strategies and their effect during exercise.
METHODS: Pubmed, Web of Science and Scopus databases were searched to identify the articles published since year 2000. Two reviewers working independently extracted data and assessed the quality of the articles included. If they disagreed, a third reviewer was consulted. ROBINS-I scale was used to assess the quality of the articles, and the review has been conducted in agreement with PRISMA guidelines.
RESULTS: Twenty studies were included in this review. 84% of them presented moderate, serious or critical risk of bias. The entire of the studies assessed Tsk during exercise, but only seven studies measured it during rest or after exercise. Eighteen studies used contact thermometry to assess Tsk and the two remaining studies employed non-contact techniques. Seven studies were conducted in warm conditions (>31.5°C) and the remaining studies in moderate conditions (10°C to 26.6°C). According to cooling strategies, ice vests and water spray are effective in reducing Tsk and decreasing the risk of heat stroke.
CONCLUSIONS: The 90% of the studies applied contact thermometry and due to their effect in the data assessed, it is necessary more research into the SCI population using infrared thermography due to its differences in characteristics, methodology, and applications. The methodological differences among studies make difficult to perform a meta-analysis.

Background and Objectives: The purpose of this systematic review is to synthesize the influence cooling modality has on survival with and without medical complications from exertional heat stroke (EHS) in sport and military populations. Methods and Materials: All peer-reviewed case reports or series involving EHS patients were searched in the following online databases: PubMed, Scopus, SPORTDiscus, Medline, CINAHL, Academic Search Premier, and the Cochrane Library: Central Registry of Clinical Trials. Cooling methods were subdivided into \"adequate\" (>0.15 °C/min) versus \"insufficient\" (<0.15 °C/min) based on previously published literature on EHS cooling rates. Results: 613 articles were assessed for quality and inclusion in the review. Thirty-two case reports representing 521 EHS patients met the inclusion criteria. Four hundred ninety-eight (498) patients survived EHS (95.58%) and 23 (4.41%) patients succumbed to complications. Fischer\'s Exact test on 2 × 2 contingency tables and relative risk ratios were calculated to determine if modality cooling rate was associated with patient outcomes. EHS patients that survived who were cooled with an insufficient cooling rate had a 4.57 times risk of medical complications compared to patients who were treated by adequate cooling methods, regardless of setting (RR = 4.57 (95%CI: 3.42, 6.28)). Conclusions: This is the largest EHS dataset yet compiled that analyzes the influence of cooling rate on patient outcomes. Zero patients died (0/521, 0.00%) when treatment included a modality with an adequate cooling rate. Conversely, 23 patients died (23/521, 4.41%) with insufficient cooling. One hundred seventeen patients (117/521, 22.46%) survived with medical complications when treatment involved an insufficient cooling rate, whereas, only four patients had complications (4/521, 0.77%) despite adequate cooling. Cooling rates >0.15 °C/min for EHS patients were significantly associated with surviving EHS without medical complications. In order to provide the best standard of care for EHS patients, an aggressive cooling rate >0.15 °C/min can maximize survival without medical complications after exercise-induced hyperthermia.