[Mesoamerican nephropathy - a new challenge for occupational physicians]. / Nefropatia mezoamerykanska ­ nowe wyzwanie dla lekarzy medycyny pracy.

Mesoamerican nephropathy (MeN) is an endemic form of chronic kidney disease (CKD) that is not related to risk factors for CKD, such as diabetes and hypertension. It primarily affects men, rural and agricultural laborers, who work in an extremely hot and dry environment. The greatest increase in the prevalence of CKD, particularly since the late 1990s, has been reported in Central America and Southern Mexico, where the prevalence is almost 9 times higher than in the USA. The highest mortality associated with CKD is reported in El Salvador where a 10-fold increase was recorded in 1984-2005. In histological examination, MeN patients manifest tubulointerstitial lesions and, in some cases, also lesions in the glomeruli. The cause of MeN remains unclear. Repeated episodes of occupational heat stress, and sweating accompanied by water loss, have a significant impact on the disease development. The disease is a significant social and economic problem, and a challenge in the field of diagnostics, therapy and prevention for physicians of many specialties, especially for occupational physicians. Med Pr. 2020;71(3):353-61.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update.

The Wilderness Medical Society convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures, as well as best practice recommendations for both field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and balance the benefits and risks or burdens for each modality. This is an updated version of the original Wilderness Medical Society Practice Guidelines for the Treatment and Prevention of Heat-Related Illness published in 2013.

Timing and Predictors of Mild and Severe Heat Illness among New Military Enlistees.

PURPOSE: Heat illnesses are important and potentially fatal conditions among physically active individuals. We determined predictors of heat illness among enlistees in a large military population experiencing common physical activity patterns. METHODS: We estimated the adjusted odds of mild (MHI) and severe (SHI) heat illness associated with demographic, health-related, and geographic factors among active-duty, US Army soldiers enlisting between January 2011 and December 2014 (N = 238,168) using discrete-time multivariable logistic regression analyses. RESULTS: We observed 2612 incident cases of MHI and 732 incident cases of SHI during 427,922 person-years of follow-up, with a mean and median of 21.6 and 21 months per subject. During the first 6 duty months, 71.3% of the MHIs and 60.2% of the SHIs occurred, peaking at month 2. The odds of MHI quadrupled among those with prior SHI (odds ratio [OR], 4.02; 95% confidence interval [CI], 2.67-6.03). Body mass index (BMI) extremes increased the odds substantially (OR at BMI ≥30 kg·m: for MHI, 1.41 (CI, 1.19-1.67); for SHI, 1.94 (CI, 1.47-2.56); OR at BMI <18.5 kg·m: for MHI, 1.50 (CI, 1.01-2.21); for SHI, 2.26 (CI, 1.16-4.39)). Tobacco use was associated with a 55% increase (CI, 1.37-1.77) in MHI odds. The odds of MHI increased if taking nonsteroidal anti-inflammatory drugs, opioids, or methylphenidate stimulants. Lower age and lower entry aptitude scores were associated with progressively increased MHI odds. CONCLUSIONS: Most heat illnesses occurred at the outset of service, indicating the need for focused prevention methods at the initiation of military duty. Prior heat illness, BMI extremes, medications, and tobacco use represent potentially actionable risk factors to address by education, policy, and/or clinician intervention.

Classification of Heat-Related Illness Symptoms Among Florida Farmworkers.

BACKGROUND: Farmworkers working in hot and humid environments have an increased risk for heat-related illness (HRI) if their thermoregulatory capabilities are overwhelmed. The manifestation of heat-related symptoms can escalate into life-threatening events. Increasing ambient air temperatures resulting from climate change will only exacerbate HRI in vulnerable populations. We characterize HRI symptoms experienced by farmworkers in three Florida communities. METHODS: A total of 198 farmworkers enrolled in 2015-2016 were asked to recall if they experienced seven HRI symptoms during the previous work week. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between selected sociodemographic characteristics and reporting three or more symptoms. Latent class analysis was used to identify classes of symptoms representing the HRI severity range. We examined sociodemographic characteristics of the farmworkers across the latent classes. RESULTS: The mean age (±SD) of farmworkers was 38.0 (±8) years; the majority were female (60%) and Hispanic (86%). Most frequently reported symptoms were heavy sweating (66%), headache (58%), dizziness (32%), and muscle cramps (30%). Females had three times the odds of experiencing three or more symptoms (OR = 2.86, 95% CI 1.18-6.89). Symptoms fell into three latent classes, which included mild (heavy sweating; class probability = 54%), moderate (heavy sweating, headache, nausea, and dizziness; class probability = 24%), and severe (heavy sweating, headache, nausea, dizziness, muscle cramps; class probability = 22%). CONCLUSIONS: Farmworkers reported a high burden of HRI symptoms that appear to cluster in physiologic patterns. Unrecognized accumulation of symptoms can escalate into life-threatening situations if untreated. Our research can inform interventions to promote early recognition of HRI, on-site care, and appropriate occupational health policy. Administrative or engineering workplace controls may also reduce the manifestation of HRI. CLINICAL RELEVANCE: This study advances the current knowledge of HRI symptoms in farmworkers and moves beyond reporting individual symptoms by utilizing latent class analysis to identify how symptoms tend to co-occur together in this population. It acknowledges multiple symptoms occurring as a result of occupational heat exposure and highlights the importance of symptom recognition.

Effect of WBGT Index Measurement Location on Heat Stress Category Classification.

UNLABELLED: The location of the wet bulb globe temperature (WBGT) index measurement may affect heat stress flag category classification. PURPOSE: This study aimed to compare WBGT measurements at three locations along the Boston Marathon race course and compare WBGT estimates for meteorological stations and 72-h advanced WBGT forecasts. METHODS: WBGT was measured hourly from 1000 to 1400 h at approximately 7 km, approximately 18 km, and approximately 30 km on the Boston Marathon race course. Simultaneous WBGT estimates were made for two meteorological stations southeast of the course via a commercial online system, which also provided 72-h advanced forecasts. RESULTS: The measurement difference (mean ± SD) among course locations was 0.2°C ± 1.8°C WBGT (ANOVA, P > 0.05). The difference between course and stations was 1.9°C ± 2.4°C WBGT (t-test, P < 0.05). Station values underestimated (n = 98) or overestimated (n = 13) course values by >3°C WBGT (>0.5 flag category) in 111 of 245 paired comparisons (45%). Higher black globe and lower wet bulb temperatures explained over- and underestimates, respectively. Significant underestimates of WBGT resulted in misclassification of green (labeled white) and black (labeled red) course flag categories (χ2, P < 0.05). Forecast data significantly underestimated red (labeled amber) and black (labeled red) course flag categories. CONCLUSIONS: Differences in WBGT index along 23 km of the Boston Marathon race route can be small enough to warrant single measurements. However, significant misclassification of flag categories occurred using WBGT estimates for meteorological stations; thus, local measurements are preferred. If the relation between station WBGT forecasts and the race sites can be established, the forecast WBGT values could be corrected to give advanced warning of approximate flag conditions. Similar work is proposed for other venues to improve heat stress monitoring.

Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update.

The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.

A new 'bio-comfort' perspective for Melbourne based on heat stress, air pollution and pollen.

Humans are at risk from exposure to extremes in their environment, yet there is no consistent way to fully quantify and understand the risk when considering more than just meteorological variables. An outdoor 'bio-comfort' threshold is defined for Melbourne, Australia using a combination of heat stress, air particulate concentration and grass pollen count, where comfortable conditions imply an ideal range of temperature, humidity and wind speed, acceptable levels of air particulates and a low pollen count. This is a new approach to defining the comfort of human populations. While other works have looked into the separate impacts of different variables, this is the first time that a unified bio-comfort threshold is suggested. Composite maps of surface pressure are used to illustrate the genesis and evolution of the atmospheric structures conducive to an uncomfortable day. When there is an uncomfortable day due to heat stress conditions in Melbourne, there is a high pressure anomaly to the east bringing warm air from the northern interior of Australia. This anomaly is part of a slow moving blocking high originating over the Indian Ocean. Uncomfortable days due to high particulate levels have an approaching cold front. However, for air particulate cases during the cold season there are stable atmospheric conditions enhanced by a blocking high emanating from Australia and linking with the Antarctic continent. Finally, when grass pollen levels are high, there are northerly winds carrying the pollen from rural grass lands to Melbourne, due to a stationary trough of low pressure inland. Analysis into days with multiple types of stress revealed that the atmospheric signals associated with each type of discomfort are present regardless of whether the day is uncomfortable due to one or multiple variables. Therefore, these bio-comfort results are significant because they offer a degree of predictability for future uncomfortable days in Melbourne.

Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness.

The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat-related illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best-practice recommendations for both field- and hospital-based therapeutic management of heat-related 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.

[Classification of heat illness].

In the type of heat illness, several medical terms such as heat syncope, heat cramp, heat exhaustion, heat stroke are included. But their Japanese medical terms are neither unified nor clearly defined. To eliminate this problem, the new classification for heat illness is proposed. By the severity of heat illness, they are divided into three grades. Grade I is corresponded to heat cramp and heat syncope. Grade III is corresponded to heat stroke, and used for any one of the three following clinical findings, (1) Central nervous system dysfunction, i.e., consciousness disturbance, seizure, ataxia. (2) Liver and kidney dysfunction. (3) Clotting disorder, i.e., DIC. This classification can be beneficial not only to the diagnosis in the hospital, but also to the early detection and management of heat illness in the field.

A modern classification of the exercise-related heat illnesses.

This article proposes a novel framework classification for the heat illnesses. It argues that heat stroke is the only described condition that is truly a "heat illness" since it is the only condition in which there is clear evidence for a pathological elevation of the core body temperature. If this is correct the non-descript terms such as heat fatigue, heat exhaustion and heat syncopy should be removed from the modern lexicon. Since the evidence is that most cases of post-exercise collapse are due to the development of postural hypotension immediately on the cessation of exercise, it is further proposed that more specific terms such as exercise-associated postural hypotension should be used, when appropriate, to replace the non-descript terms such as heat exhaustion, heat fatigue or heat syncopy. Furthermore this novel classification acknowledges that heat stroke may occur in some as a result of accelerated rates of endogenous heat production (thermogenesis). It also suggests that the elevated body temperature alone may not be the sole cause of fatal outcomes in heat stroke but that toxic chemicals released from damaged muscles by the processes causing this accelerated thermogenesis may also be involved.

Environmental factors influencing heat stress in feedlot cattle.

Data from 3 summer feedlot studies were utilized to determine the environmental factors that influence heat stress in cattle and also to determine wind speed (WSPD; m.s(-1)) and solar radiation (RAD; W.m(-2)) adjustments to the temperature-humidity index (THI). Visual assessments of heat stress, based on panting scores (0 = no panting to 4 = severe panting), were collected from 1400 to 1700. Mean daily WSPD, black globe temperature at 1500, and minimums for nighttime WSPD, nighttime black globe THI, and daily relative humidity were found to have the greatest influence on panting score from 1400 to 1700 (R2 = 0.61). From hourly values for THI, WSPD, and RAD, panting score was determined to equal -7.563 + (0.121 x THI) - (0.241 x WSPD) + (0.00082 x RAD) (R2 = 0.49). Using the ratio of WSPD to THI and RAD to THI (- 1.992 and 0.0068 for WSPD and RAD, respectively), adjustments to the THI were derived for WSPD and RAD. On the basis of these ratios and the average hourly data for 1400 to 1700, the THI, adjusted for WSPD and RAD, equals [4.51 + THI - (1.992 x WSPD) + (0.0068 x RAD)]. Four separate cattle studies, comparable in size, type of cattle, and number of observations to the 3 original studies, were utilized to evaluate the accuracy of the THI equation adjusted for WSPD and RAD, and the relationship between the adjusted THI and panting score. Mean panting score derived from individual observations of black-hided cattle in these 4 studies were 1.22, 0.94, 1.32, and 2.00 vs. the predicted panting scores of 1.15, 1.17, 1.30, and 1.96, respectively. Correlations between THI and panting score in these studies ranged from r = 0.47 to 0.87. Correlations between the adjusted THI and mean panting score ranged from r = 0.64 to 0.80. These adjustments would be most appropriate to use, within a day, to predict THI during the afternoon hours using hourly data or current conditions. In addition to afternoon conditions, nighttime conditions, including minimum WSPD, minimum black globe THI, and minimum THI, were also found to influence heat stress experienced by cattle. Although knowledge of THI alone is beneficial in determining the potential for heat stress, WSPD and RAD adjustments to the THI more accurately assess animal discomfort.

Heat illness in athletes: the dangerous combination of heat, humidity and exercise.

In 1980, 1700 people died during a prolonged heat wave in a region under-prepared for heat illness prevention. Dramatically underreported, heat-related pathology contributes to significant morbidity as well as occasional mortality in athletic, elderly, paediatric and disabled populations. Among US high school athletes, heat illness is the third leading cause of death. Significant risk factors for heat illness include dehydration, hot and humid climate, obesity, low physical fitness, lack of acclimatisation, previous history of heat stroke, sleep deprivation, medications (especially diuretics or antidepressants), sweat gland dysfunction, and upper respiratory or gastrointestinal illness. Many of these risk factors can be addressed with education and awareness of patients at risk. Dehydration, with fluid loss occasionally as high as 6-10% of bodyweight, appears to be one of the most common risk factors for heat illness in patients exercising in the heat. Core body temperature has been shown to rise an additional 0.15-0.2 degrees C for every 1% of bodyweight lost to dehydration during exercise. Identifying athletes at risk, limiting environmental exposure, and monitoring closely for signs and symptoms are all important components of preventing heat illness. However, monitoring hydration status and early intervention may be the most important factors in preventing severe heat illness.

Heat strain reduction by ice-based and vapor compression liquid cooling systems with a toxic agent protective uniform.

BACKGROUND: The purpose of this study was to compare a vapor compression microclimate cooling system (MCC) and a personal ice cooling system (PIC) for their effectiveness in reducing physiological strain when used with cooling garments worn under the impermeable self-contained toxic environment protective outfit (STEPO). A second comparison was done between the use of total body (TOTAL) and hooded shirt-only (SHIRT) cooling garments with both the MCC and PIC systems. It was hypothesized that the cooling systems would be equally effective, and total body cooling would allow 4 h of physical work in the heat while wearing STEPO. METHODS: Eight subjects (six men, two women) attempted four experiments at 38 degrees C (100 degrees F), 30% rh, 0.9 m x sec(-1) wind, while wearing the STEPO. Subjects attempted 4 h of treadmill walking (rest/exercise cycles of 10/20 min) at a time-weighted metabolic rate of 303 +/- 50 W. RESULTS: Exposure time was not different between MCC and PIC, but exposure time was greater with TOTAL (131 +/- 66 min) than with SHIRT (83 +/- 27 min) for both cooling systems (p < 0.05). Cooling rate was not different between MCC and PIC, but cooling rate while wearing TOTAL (362 +/- 52 W) was greater than with SHIRT (281 +/- 48 W) (p < 0.05). Average heat storage was lower with MCC (39 +/- 20 W x m(-2)) than with PIC (50 +/- 17 W x m(-2)) in both TOTAL and SHIRT (p < 0.05). Also, average heat storage while wearing TOTAL (34 +/- 19 W x m(-2)) was less than with SHIRT (55 +/- 13 W x m(-2)) for both cooling systems (p < 0.05). The Physiological Strain Index (PSI) was lower in MCC-TOTAL (2.4) than MCC-SHIRT (3.7), PIC-SHIRT (3.8), and PIC-TOTAL (3.3) after 45 min of heat exposure (p < 0.05). CONCLUSIONS: Total body circulating liquid cooling was more effective than shirt-only cooling under the impermeable STEPO uniform, providing a greater cooling rate, allowing longer exposure time, and reducing the rate of heat storage. The MCC and PIC systems were equally effective during heat exposure, but neither system could extend exposure for the 4 h targeted time.

Wet bulb globe temperature (WBGT)--to what extent is GT essential?

BACKGROUND: Industrial and military safety personnel often require an easy, quick and accurate assessment of heat stress as a potential risk. The widely used WBGT index to evaluate heat stress is cumbersome and suited for a fixed site station rather than a mobile situation. Recently, a modified discomfort index (MDI) compiled from ambient temperature (Ta) and wet bulb temperature (Tw) was suggested to evaluate heat stress. HYPOTHESIS: Validation of the simple and easy-to-operate MDI on an independent database can determine whether this index is able to serve as a reliable and valid alternative to WBGT. METHODS: Four separate database sets obtained from the Marine Corps Training Site on Parris Island, SC, served to validate this index. Hourly weather measurements were collected daily during 4 yr, representing a wide range of environmental conditions. RESULTS: The MDI validity was tested vs. the WBGT index. A highly significant correlation coefficient (r) greater than 0.95 (p < 0.001) was found in each of the four database sets. CONCLUSIONS: The simply constructed and user friendly MDI is easier to calculate and use than WBGT, and it has the potential to serve as an attractive alternative to the WBGT index in assessing heat stress.

Transtorno do estresse pós-traumatico: definiçao, classificaçäo e tratamento / Post-traumatic stress disorder: definition, classification and treatment

As consequências psicológicas de evento traum tico foram descritas h muito tempo. Entretanto, somente em 1980, os critérios diagnósticos do transtorno do estresse pós-traum tico(PSTD) foram incluídos no manual de classificaçäo dos transtornos psiqui tricos da Associaçäo Psiqui trica Americana. A partir disso, houve aumento consider vel no número de publicaçöes sobre PTSD, incluindo modelos etiológicos, conceitualizaçäo e tratamento com abordagens medicamentosas e psicoter picas. No Brasil, nota-se ainda certo desconhecimento a respeito desse assunto. Este trabalho apresenta revisäo da literatura atual sobre os diversos aspectos do PTSD e tem a finalidade de informar profissionais da rea de saúde para melhor atendimento aos portadores desse transtorno

Heat illness in the services.

In spite of considerable progress in prevention, heat illness remains a significant occupational risk in the Services. A retrospective analysis of cases reported through the Defence Analytical Services Agency for the years 1981-91 shows higher numbers in the second part of this period, though this may be due to reporting differences. Overall, there was an average of 135 servicemen and women admitted to hospital each year for heat-related conditions though only 15.5 of them required sick leave for more than a week. Annual incidence was higher in the Army (73 per 100,000) than in the RN (14) and the RAF (5). Tri-service incidence was 42 per 100,000 for males and 11 for females. There were 11 deaths, all in the Army, but only 5 servicemen were discharged because of heat illness. Although the largest number of cases was reported from Great Britain, the incidence of cases in troops in Hong Kong and Cyprus was greater. In all locations, cases occurred in the coldest part of the year, but were commoner in the warmer months. Heat exhaustion (73.6%) seems more frequent than heat stroke (13%), but there are problems with definition and reporting. Current preventive measures are outlined and suggestions are made for more accurate monitoring of heat illness in the future. In the light of recent literature, recommendations are made for the grading and management of servicemen following heat illness.