A systematic review of body temperature variations in older people

Electroacupuncture stimulation improves cognitive ability and regulates metabolic disorders in Alzheimer's disease model mice: new insights from brown adipose tissue thermogenesis

Background

Metabolic defects play a crucial role in Alzheimer's disease (AD) development. Brown adipose tissue (BAT) has been identified as a novel potential therapeutic target for AD due to its unique role in energy metabolism. Electroacupuncture (EA) shows promise in improving cognitive ability and brain glucose metabolism in AD, but its effects on peripheral and central metabolism are unclear.

Methods

In this study, SAMP8 mice (AD model) received EA stimulation at specific acupoints. Cognitive abilities were evaluated using the Morris water maze test, while neuronal morphology and tau pathology were assessed through Nissl staining and immunofluorescence staining, respectively. Metabolic variations and BAT thermogenesis were measured using ELISA, HE staining, Western blotting, and infrared thermal imaging.

Results

Compared to SAMR1 mice, SAMP8 mice showed impaired cognitive ability, neuronal damage, disrupted thermoregulation, and metabolic disorders with low BAT activity. Both the EA and DD groups improved cognitive ability and decreased tau phosphorylation (p<0.01 or p<0.05). However, only the EA group had a significant effect on metabolic disorders and BAT thermogenesis (p<0.01 or p<0.05), while the DD group did not.

Conclusion

These findings indicate that EA not only improves the cognitive ability of SAMP8 mice, but also effectively regulates peripheral and central metabolic disorders, with this effect being significantly related to the activation of BAT thermogenesis.

Infrared Thermography in Symptomatic Knee Osteoarthritis: Joint Temperature Differs Based on Patient and Pain Characteristics

The aim of this study was to evaluate osteoarthritis (OA) patients with infrared thermography to investigate imaging patterns as well as demographic and clinical characteristics that influence knee inflammation. Forty patients with one-sided symptomatic knee OA were included and evaluated through knee-specific PROMs and the PainDETECT Questionnaire for neuropathic pain evaluation. Thermograms were captured using a thermographic camera FLIR-T1020 and temperatures were extracted using the software ResearchIR for the overall knee and the five ROIs: medial, lateral, medial patella, lateral patella, and suprapatellar. The mean temperature of the total knee was 31.9 ± 1.6 °C. It negatively correlated with age (rho = −0.380, p = 0.016) and positively correlated with BMI (rho = 0.421, p = 0.007) and the IKDC objective score (tau = 0.294, p = 0.016). Men had higher temperatures in the knee medial, lateral, and suprapatellar areas (p = 0.017, p = 0.019, p = 0.025, respectively). Patients with neuropathic pain had a lower temperature of the medial knee area (31.5 ± 1.0 vs. 32.3 ± 1.1, p = 0.042), with the total knee negatively correlating with PainDETECT (p = 0.045). This study demonstrated that the skin temperature of OA symptomatic knees is influenced by demographic and clinical characteristics of patients, with higher joint temperatures in younger male patients with higher BMI and worst objective knee scores and lower temperatures in patients affected by neuropathic pain.

Feasibility, Acceptability, and Performance of a Continuous Temperature Monitor in Older Adults and Staff in Congregate-Living Facilities

OBJECTIVES

Residents of congregate-living facilities are susceptible to disability and mortality from infection given the presence of advanced age, multimorbidity, and frailty-as demonstrated in the recent COVID pandemic. This study assessed the feasibility, acceptability, and applicability of a continuous temperature monitoring device in a congregate-living facility with residents of independent living, assisted living, and their care-providing staff. We hypothesized that a wearable device compared with daily manual temperature assessment would be well tolerated and more effective at detecting temperature variances than current standard of care body temperature assessment.

DESIGN

Feasibility study.

SETTING AND PARTICIPANTS

Residents of assisted and independent living and staff of a retirement community.

METHODS

Thirty-five participants, including residents in assisted- and independent-living facilities (25) and staff (10) were enrolled in a 90-day feasibility study and wore a continuous temperature sensor from March to July 2021. Primary outcomes included study completion, ability to reapply the sensor, temperature data acquisition, and data availability from the sensors. A secondary analysis of the temperature data involved comparing the method of obtaining temperature using the continuous monitoring device against standard of care using traditional manual thermometers.

RESULTS

Overall, 91.3% of residents, who were in the study during the first reapplication, were able to apply the device without assistance (21 of 23), and 80% of resident participants completed the study (20 of 25). For staff participants, completion rates and reapplication rates were 100%. Data acquisition rates from the continuous temperature devices were much higher than manual temperatures. Four episodes of fever were detected by the devices; manual temperature checks did not identify these events.

CONCLUSIONS AND IMPLICATIONS

Continuous temperature monitoring in an older adult population and the staff in congregate-living facilities is feasible and acceptable. This approach identified fever undetected by current standard of care indicating the capability of this device for earlier detection of fevers.

The effect of age on fever response among nursing home residents with SARS-COV-2 infection

Over 15,000 veterans in 135 VA nursing homes were systematically tested for SARS-CoV-2 and had daily temperatures assessed from March to August, 2020. Lower baseline temperatures, and in SARS-CoV-2+ , lower maximum temperatures were observed with advancing age. Clinicians should be aware of the potential diminished fever response in the elderly with SARS-CoV-2.

Climate change and neurodegenerative diseases

The climate change induced global warming, and in particular the increased frequency and intensity of heat waves, have been linked to health problems. Among them, scientific works have been reporting an increased incidence of neurological diseases, encompassing also neurodegenerative ones, such as Dementia of Alzheimer's type, Parkinson's Disease, and Motor Neuron Diseases. Although the increase in prevalence of neurodegenerative diseases is well documented by literature reports, the link between global warming and the enhanced prevalence of such diseases remains elusive. This is the main theme of our work, which aims to examine the connection between high temperature exposure and neurodegenerative diseases. Firstly, we evaluate the influence of high temperatures exposure on the pathophysiology of these disorders. Secondly, we discuss its effects on the thermoregulation, already compromised in affected patients, and its interference with processes of excitotoxicity, oxidative stress and neuroinflammation, all of them related with neurodegeneration. Finally, we investigate chronic versus acute stressors on body warming, and put forward a possible interpretation of the beneficial or detrimental effects on the brain, which is responsible for the incidence or progression of neurological disorders.

Assessment of the impact of age and of blood-derived inflammatory markers in horses with colitis

OBJECTIVES

To determine the impact of age on survival in horses with colitis and to elucidate whether a lower type-1/type-2 cytokine ratio or an exaggerated inflammatory state contribute to reduced survival in aged horses.

DESIGN

Part 1: Retrospective cohort analysis. Part 2: Analytic observational study.

ANIMALS

Part 1: One hundred twenty-four adult horses with colitis. Part 2: Twenty-nine adult horses with new diarrhea onset while hospitalized.

MEASUREMENTS AND MAIN RESULTS

Part 1: Patient signalment, select clinicopathological data, diagnoses, treatment, hospitalization length, and invoice were compared between survivors (n = 101) and nonsurvivors (n = 23). Only age and plasma transfusion retained statistical significance in the final multivariate outcome model, with 8.5 times lower odds of survival in transfused horses (95% confidence interval [CI], 2.6-27.2%). Additionally, the likelihood of nonsurvival increased by 11.8% (95% CI, 4-20.2%) for every year the horse aged (P = 0.002). Similarly, geriatric horses (≥20 years) were 15.2 times more likely to die than young-adults (2-12 years, P = 0.03), independent of financial investment, documented comorbidities, and duration of hospitalization. Part 2: Select cytokine analyses were performed on serum collected from hospitalized horses within 1 hour of diarrhea onset (T0) and 6 hours later. At T0, all recorded clinicopathological variables were comparable between geriatric and young-adult horses, suggesting a similar degree of systemic illness. The median concentration of type-2 cytokines interleukin-4 and interleukin-10, and type-1 cytokine interferon-γ did not differ between age groups. Inflammatory cytokines interleukin-6 and tumor necrosis factor-α were significantly higher in geriatric compared to young-adult horses at both sampling time points.

CONCLUSIONS

Outcome of colitis was less favorable in aging horses and patients receiving a plasma transfusion. Although an exaggerated inflammatory state, based on increased interleukin-6 and tumor necrosis factor-α concentrations, in geriatric horses may contribute to reduced survival, a lower type-1/type-2 cytokines ratio was not identified in our geriatric population.

COVID-19 disease trajectories among nursing home residents

Introduction

Older adults are at greater risk of both infection with and mortality from COVID‐19. Many U.S. nursing homes have been devastated by the COVID‐19 pandemic, yet little has been described regarding the typical disease course in this population. The objective of this study is to describe and identify patterns in the disease course of nursing home residents infected with COVID‐19.

Setting and Methods

This is a case series of 74 residents with COVID‐19 infection in a nursing home in central Indiana between March 28 and June 17, 2020. Data were extracted from the electronic medical record and from nursing home medical director tracking notes from the time of the index infection through August 31, 2020. The clinical authorship team reviewed the data to identify patterns in the disease course of the residents.

Results

The most common symptoms were fever, hypoxia, anorexia, and fatigue/malaise. The duration of symptoms was extended, with an average of over 3 weeks. Of those infected 25 died; 23 of the deaths were considered related to COVID‐19 infection. A subset of residents with COVID‐19 infection experienced a rapidly progressive, fatal course.

Discussion/Conclusions

Nursing home residents infected with COVID‐19 from the facility we studied experienced a prolonged disease course regardless of the severity of their symptoms, with implications for the resources needed to care for and support of these residents during active infection and post‐disease. Future studies should combine data from nursing home residents across the country to identify the risk factors for disease trajectories identified in this case series.

Body Temperature Is Associated With Cognitive Performance in Older Adults With and Without Mild Cognitive Impairment: A Cross-sectional Analysis

Wearable devices for remote and continuous health monitoring in older populations frequently include sensors for body temperature measurements (i.e., skin and core body temperatures). Healthy aging is associated with core body temperatures that are in the lower range of age-related normal values (36.3 ± 0.6°C, oral temperature), while patients with Alzheimer's disease (AD) exhibit core body temperatures above normal values (up to 0.2°C). However, the relation of body temperature measures with neurocognitive health in older adults remains unknown. This study aimed to explore the association of body temperature with cognitive performance in older adults with and without mild cognitive impairment (MCI). Eighty community-dwelling older adults (≥65 years) participated, of which 54 participants were cognitively healthy and 26 participants met the criteria for MCI. Skin temperatures at the rib cage and the scapula were measured in the laboratory (single-point measurement) and neuropsychological tests were conducted to assess general cognitive performance, episodic memory, verbal fluency, executive function, and processing speed. In a subgroup (n = 15, nine healthy, six MCI), skin and core body temperatures were measured continuously during 12 h of habitual daily activities (long-term measurement). Spearman's partial correlation analyses, controlled for age, revealed that lower median body temperature and higher peak-to-peak body temperature amplitude was associated with better general cognitive performance and with better performance in specific domains of cognition; [e.g., rib median skin temperature (single-point) vs. processing speed: rs = 0.33, p = 0.002; rib median skin temperature (long-term) vs. executive function: rs = 0.56, p = 0.023; and peak-to-peak core body temperature amplitude (long-term) vs. episodic memory: rs = 0.51, p = 0.032]. Additionally, cognitively healthy older adults showed lower median body temperature and higher peak-to-peak body temperature amplitude compared to older adults with MCI (e.g., rib median skin temperature, single-point: p = 0.035, r = 0.20). We conclude that both skin and core body temperature measures are potential early biomarkers of cognitive decline and preclinical symptoms of MCI/AD. It may therefore be promising to integrate body temperature measures into multi-parameter systems for the remote and continuous monitoring of neurocognitive health in older adults.

One size does not fit all: Assuming the same normal body temperature for everyone is not justified

Despite the increasing personalization of medicine, surprisingly ~37.0°C (98.6°F) continues as the estimate of normal temperature. We investigated between-subject and within-subject thermal variability, whether a significant percentage of individuals have a low mean oral temperature, and whether these differ by sex, age, time of day, ethnicity, body mass index (BMI), or menstrual phase. Oral temperature was measured by Life Brand^® Fast-Read Digital Oral Thermometers and sampled 14 times over two weeks, seven morning and seven evening readings. The volunteer sample consisted of 96 adults (42 men, 54 women; 27 couples, 42 singletons), ages 18–67 years. We found sizeable individual differences in body temperature and that the normal temperature of many individuals is considerably lower than 37.0°C (98.6°F). Mean temperatures ranged from 35.2°C (95.4°F) to 37.4°C (99.3°F). The mean temperature across all participants was 36.1°C (97.0°F)—lower than most studies have reported, consistent with recent evidence of temperature declining over decades. 77% had mean temperatures at least 0.55°C (1°F) lower than 37.0°C (98.6°F). Mean temperature did not differ by age, but women had higher temperatures than men, even within a couple with room temperature and warmth of clothing equated. Although oral temperature varied widely across individuals, it showed marked stability within individuals over days. Variability of temperature over days did not differ by sex, but was larger among younger adults. Using 37.0°C (98.6°F) as the assumed normal temperature for everyone can result in healthcare professionals failing to detect a serious fever in individuals with a low normal temperature or obtaining false negatives for those individuals when using temperature to screen for COVID-19, mistaking their elevated temperature as normal. Some have called for lowering the estimate of normal temperature slightly (e.g., 0.2°C [0.36°F]). That still seems an overly high estimate. More important, using any standardized “normal” temperature will lead to errors for many people. Individual differences are simply too great. Personalizing body temperature is needed. Temperature could be measured at yearly doctor visits, as blood pressure is now. That would be simple to implement. Since our results show marked thermal stability within an individual, sampling temperature only once yearly could provide an accurate indication of a person’s normal temperature at that time of day. Such records over time would also provide a more accurate understanding of how temperature changes over the lifespan.

Noncontact Body Temperature Measurement: Uncertainty Evaluation and Screening Decision Rule to Prevent the Spread of COVID-19

The need to measure body temperature contactless and quickly during the COVID-19 pandemic emergency has led to the widespread use of infrared thermometers, thermal imaging cameras and thermal scanners as an alternative to the traditional contact clinical thermometers. However, limits and issues of noncontact temperature measurement devices are not well known and technical–scientific literature itself sometimes provides conflicting reference values on the body and skin temperature of healthy subjects. To limit the risk of contagion, national authorities have set the obligation to measure body temperature of workers at the entrance to the workplace. In this paper, the authors analyze noncontact body temperature measurement issues from both clinical and metrological points of view with the aim to (i) improve body temperature measurements accuracy; (ii) estimate the uncertainty of body temperature measurement on the field; (iii) propose a screening decision rule for the prevention of the spread of COVID-19. The approach adopted in this paper takes into account both the traditional instrumental uncertainty sources and clinical–medical ones related to the subjectivity of the measurand. A proper screening protocol for body temperature measurement considering the role of uncertainty is essential to correctly choose the threshold temperature value and measurement method to access critical places during COVID-19 pandemic emergency.

Effect of perioperative acetaminophen on body temperature after cardiovascular surgery with cardiopulmonary bypass: A single-center retrospective study

Context:

Postoperative hyperthermia, which may lead to cognitive decline, is a common complication of cardiovascular surgery with cardiopulmonary bypass (CPB).

Aims:

The aim of this study was to examine the effectiveness of perioperative intravenous acetaminophen on body temperature in adult patients after cardiovascular surgery with CPB.

Settings and Design:

This was a single-center retrospective study focusing on adult patients who underwent elective cardiovascular surgery with CPB at a university hospital in Japan.

Subjects and Methods:

Patients were divided into two groups based on whether they received acetaminophen perioperatively. In the acetaminophen group, 15 mg/kg intravenous acetaminophen solution was infused at 30 min after discontinuation of CPB and every 6 h after intensive care unit (ICU) admission.

Statistical Analysis Used:

The primary outcome was the maximum axillary temperature within 12 h after ICU admission. The effects of acetaminophen on postoperative body temperature were estimated by the standardization and inverse probability weighting using propensity scores.

Results:

A total of 201 patients were included in the final analysis (acetaminophen group, n = 101; non-acetaminophen group, n = 100). The maximum axillary temperature within 12 h after ICU admission was 37.20 ± 0.54°C in the acetaminophen group and 37.78 ± 0.59°C in the non-acetaminophen group. Acetaminophen lowered the standardized mean of primary endpoint (−0.54°C, 95% confidence interval, −0.69 to −0.38) compared to non-acetaminophen.

Conclusions:

Perioperative intravenous acetaminophen inhibited body temperature elevation after cardiovascular surgery with CPB, compared with the non-acetaminophen group.

Age-Related Changes in the Thermoregulatory Properties in Bank Voles From a Selection Experiment

As with many physiological performance traits, the capacity of endotherms to thermoregulate declines with age. Aging compromises both the capacity to conserve or dissipate heat and the thermogenesis, which is fueled by aerobic metabolism. The rate of metabolism, however, not only determines thermogenic capacity but can also affect the process of aging. Therefore, we hypothesized that selection for an increased aerobic exercise metabolism, which has presumably been a crucial factor in the evolution of endothermic physiology in the mammalian and avian lineages, affects not only the thermoregulatory traits but also the age-related changes of these traits. Here, we test this hypothesis on bank voles (Myodes glareolus) from an experimental evolution model system: four lines selected for high swim-induced aerobic metabolism (A lines), which have also increased the basal, average daily, and maximum cold-induced metabolic rates, and four unselected control (C) lines. We measured the resting metabolic rate (RMR), evaporative water loss (EWL), and body temperature in 72 young adult (4 months) and 65 old (22 months) voles at seven ambient temperatures (13-32°C). The RMR was 6% higher in the A than in the C lines, but, regardless of the selection group or temperature, it did not change with age. However, EWL was 12% higher in the old voles. An increased EWL/RMR ratio implies either a compromised efficiency of oxygen extraction in the lungs or increased skin permeability. This effect was more profound in the A lines, which may indicate their increased vulnerability to aging. Body temperature did not differ between the selection and age groups below 32°C, but at 32°C it was markedly higher in the old A-line voles than in those from other groups. As expected, the thermogenic capacity, measured as the maximum cold-induced oxygen consumption, was decreased by about 13% in the old voles from both selection groups, but the performance of old A-line voles was the same as that of the young C-line ones. Thus, the selection for high aerobic exercise metabolism attenuated the adverse effects of aging on cold tolerance, but this advantage has been traded off by a compromised coping with hot conditions by aged voles.

Risk factors for predicting mortality in elderly patients with COVID-19: A review of clinical data in China

While elderly patients are at high risk of fatality, research concerning COVID-19 has largely been done on clarifying the clinical features. As such, the present work aims to identify risk factors for mortality in elderly patients with COVID-19. Given that single-centre studies are less likely informative as elderly remains a minority in the total Chinese population, the present study reviewed the clinical data of geriatric COVID-19 patients gathered from different sources in the public domain. Based on the data of 154 individuals from 26 provinces, age remained a key mortality risk factor among geriatric patients of different ages. While dyspnoea and chest pain/discomfort were more commonly seen in deceased patients as they represented severe pneumonia, fever was more prominent in surviving patients. This was likely due to the lower baseline body temperature observed in elderly which translated to a lower maximum temperature of fever. However, lowering the threshold temperature for fever is not recommended in surveillance. Instead, baseline body temperature measured on a regular basis should be used to define the threshold temperature for fever. Against mixed results, more research should be done on identifying comorbidities associated with mortality in geriatric patients.

Hypothermia as a risk factor for Alzheimer disease

Alzheimer disease (AD), which is associated with chronic and progressive neurodegeneration, is the most prevalent cause of dementia linked to aging. Among the risk factors for AD, age stands as the greatest one, with the vast majority of people with AD being 65 years of age or older. Nevertheless, the pathophysiologic mechanisms underlying the link between aging and the development of AD, although not completely understood, might reveal important aspects for the understanding of this pathology. Thus, there is significant evidence that the impaired thermal homeostasis associated with normal aging leads to a variety of metabolic changes that could be associated with AD development. In this chapter, we assess the clinical and biochemical evidence implicating hypothermia as a risk factor for the development of AD and the impact of hypothermia on the two pathologic hallmarks of AD: accumulation of senile plaques of amyloid-beta and neurofibrillary tangles of aberrant hyperphosphorylated tau protein.

Lower temperatures reduce type I interferon activity and promote alphaviral arthritis

Chikungunya virus (CHIKV) belongs to a group of mosquito-borne alphaviruses associated with acute and chronic arthropathy, with peripheral and limb joints most commonly affected. Using a mouse model of CHIKV infection and arthritic disease, we show that CHIKV replication and the ensuing foot arthropathy were dramatically reduced when mice were housed at 30°C, rather than the conventional 22°C. The effect was not associated with a detectable fever, but was dependent on type I interferon responses. Bioinformatics analyses of RNA-Seq data after injection of poly(I:C)/jetPEI suggested the unfolded protein response and certain type I interferon responses are promoted when feet are slightly warmer. The ambient temperature thus appears able profoundly to effect anti-viral activity in the periphery, with clear consequences for alphaviral replication and the ensuing arthropathy. These observations may provide an explanation for why alphaviral arthropathies are largely restricted to joints of the limbs and the extremities.

Variation in Normal Ear Temperature

BACKGROUND

Variation in baseline ear temperature, taken in the unadjusted mode, has yet to be established in different age groups. Because normal body temperatures show large variations, the same may be expected for increased temperatures in fever. The aims were to study variations in normothermic body temperatures measured with an ear thermometer and to determine differences between actual and perceived body temperature during a febrile episode (referred to as difftemp) in apparently healthy children and adults.

METHODS

Ear temperature was measured once in 2,006 individuals (61.7% females): 683 children aged 2 and 4 years, 492 adolescents aged 10-18 years, 685 adults aged 19-65 years and 146 elderly aged 66-89 years. Difftemp was estimated as the difference between the individual's ear body temperature, measured in the present study, and the respondent's reported temperature when feverish.

RESULTS

Mean ear temperature was 36.4 ± 0.6°C overall and in the child and adult groups. In adolescents, it was 36.5 ± 0.5°C, and in elderly, 36.1 ± 0.5°C. Temperature in men was 36.3 ± 0.6°C, and in women, 36.5 ± 0.5°C. Difftemp was 1.1 ± 0.7°C in adolescents, 1.5 ± 0.7°C in children and adults, and 1.6 ± 0.7°C in those >65 years.

CONCLUSIONS

Ear body temperature is lower than traditionally reported and differs with age and sex. An individual difftemp of 1.0-1.5°C along with malaise might indicate fever.

Tympanic temperature versus temporal temperature in patients with pyrexia and chills

Accurate body temperature (BT) measurement is critical for immediate and correct estimation of core BT; measurement of changes in BT can provide physicians the initial information for selecting appropriate diagnostic approach and may prevent unnecessary diagnostic investigation. This study aimed to assess differences in tympanic and temporal temperatures among patients with fever in different conditions, especially in those with and without chills. This prospective study included patients from the emergency department between 2011 and 2012. All temperature measurements were obtained using tympanic thermometers and infrared skin thermometers. Differences in tympanic and temporal temperatures were analyzed according to 6 age groups, 5 ambient temperature groups, and 6 tympanic and temporal temperature subgroups. General linear model analysis and receiver operating characteristic curve analysis were used to estimate the differences in mean tympanic and temporal temperatures. Of the 710 patients enrolled, 246 had tympanic temperature more than 38.0°C, including 46 with chills (18.7%). Fourteen patients (3.0%) had chills and tympanic temperature less than 38°C. In the tympanic temperature subgroup of 39.0 to less than 39.5°C, approximately one-third of the patients had chills (32.3%). In the tympanic temperature subgroup of 38.0 to less than 39.0°C, the tympanic temperature was 0.4°C higher than the temporal temperature in patients without chills and 0.9°C higher in patients with chills. In the tympanic temperature subgroup of 39.0°C or more, tympanic temperature was 0.7°C higher than temporal temperature in patients without chills and 0.8°C higher in patients with chills. Temporal thermometer is more reliable in the age group of less than 1 year and 18 to less than 65 years. When the patients show tympanic temperature range of 38.0 to less than 39.0°C, 0.4°C should be added for patients without chills and 0.9°C for patients with chills to obtain core temperature. However, in patients with tympanic temperature of 39.0°C or more, 0.7°C to 0.8°C should be added, regardless of the presence of chills.

Adequacy of initial evaluation of fever in long-term care facilities

AIM

Febrile residents in long-term care facilities (LTCF) might be inadequately evaluated by caregivers. The present study aimed to examine the factors associated with inadequacy of initial fever evaluations by caregivers at night in LTCF.

METHODS

We carried out a cross-sectional study among a convenience sample of caregivers employed at 11 LTCF in Japan using a vignette-based questionnaire. The respondents were randomly assigned to one of two scenarios describing a mild or severe febrile episode in an LTCF resident at night. The respondents' thinking patterns were classified based on influential factors in their fever evaluation. Associations between adequacy of evaluation and respondents' characteristics were evaluated using generalized linear mixed models.

RESULTS

A total of 34% of fever evaluations among caregivers were considered to be inadequate regarding the necessity for examination by a physician, due in most cases to underestimating the severity of the fever. Respondents' thinking patterns in fever evaluation were significantly associated with the adequacy of the evaluation. Caregivers who placed particular importance on the preferences of residents and families versus other factors including the resident's febrile condition, were more likely to make an inadequate evaluation than those who did not.

CONCLUSIONS

Our findings here suggest that eagerness to comply with residents' preference in fever evaluation could prompt caregivers not to call for an appropriate diagnostic procedure. Geriatr Gerontol Int 2017; 17: 1294-1299.

LPS alters pattern of sickness behavior but does not affect glutathione level in aged male rats

Behavioral symptoms of sickness, such as fever and motor activity are a coordinated set of changes that develop during infection. The aim of study was to compare the sickness behaviour (SB) in healthy old and young rats treated with pyrogenic dose of endotoxin and to check their glutathione level. Before experimentation male Wistar rats were selected according to standard body mass, motor activity, and white blood cells count. Intraperitoneal injection of lipopolysaccharide (LPS) from E. coli was used to provoke SB. The level of liver glutathione, interleukin (IL) -6, deep body temperature (Tb) and motor activity were measured. Glutathione level in old and young rats did not differ significantly. In both young and old rats LPS administration provoked fever (the mean value of Tb was 38.06 ± 0.01 °C in old rats, and 38.19 ± 0.06 °C in young rats). LPS injection affected night-time activity in both groups (12 h averages were 1.56 ± 0.40 counts in old LPS-treated rats vs 2.74 ± 0.53 counts in not-treated old rats and 3.44 ± 0.60 counts for young LPS-treated vs 4.28 ± 0.57 counts for young not-treated rats). The injection of LPS provoked an elevation of plasma IL-6 concentration (from values below the lowest detectable standard in not-treated groups of animals to 6322.82 ± 537.00 pg/mL in old LPS-treated rats and 7415.62 ± 451.88 pg/mL in young LPS-treated rats). Based on these data, we conclude that good health of aged rats prevents decrease in the glutathione level. Old rats are still able to develop SB in response to pyrogenic dose of LPS, although its components have changed pattern compared to young animals.

The older adult experiencing sepsis

Sepsis is a potentially fatal response to infection affecting patients across the life span. Sepsis can progress from systemic inflammatory response to severe sepsis and septic shock if not recognized promptly and managed effectively. Risk factors for sepsis include age, gender, the presence of invasive devices (eg, urinary catheters), and chronic medical conditions (eg, chronic obstructive pulmonary disease). Sepsis awareness is essential and includes identification of population-focused risk factors, recognition of clinical signs and symptoms, and timely implementation of interventions. The purpose of this article was to examine sepsis in older adults, including prevalence, atypical presentation of the condition, and considerations for sepsis management in the elderly population.

Temperature and toxic Tau in Alzheimer's disease: new insights

Alzheimer's disease (AD), the most common dementia in the elderly, is characterized by cognitive impairment and severe autonomic symptoms such as disturbance in core body temperature (Tc), which may be predictors or early events in AD onset. Inclusions of phosphorylated Tau (p-Tau) are a hallmark of AD and other neurodegenerative disorders called “Tauopathies.” Animal and human studies show that anesthesia augments p-Tau levels through reduction of Tc, with implications for AD. Additionally, hypothermia impairs memory and cognitive function. The molecular networks related to Tc that are associated with AD remain poorly characterized. Under physiological conditions, Tau binds microtubules, promoting their assembly and stability. The dynamically regulated Tau-microtubule interaction plays an important role in structural remodeling of the cytoskeleton, having important functions in neuronal plasticity and memory in the hippocampus. Hypothermia-induced increases in p-Tau levels are significant, with an 80% increase for each degree Celsius below normothermic conditions. Although the effects of temperature on Tau phosphorylation are evident, its effects on p-Tau degradation remain poorly understoodWe review information concerning the mechanisms of Tau regulation of neuron plasticity via its effects on microtubule dynamics, with focus on pathways regulating the abundance of phosphorylated Tau species.  We highlight the effects of temperature on molecular mechanisms influencing the development of Tau-related diseases. Specifically, we argue that cold might preferentially affects central nervous system structures that are highly reliant upon plasticity, such as the hippocampus, and that the effect of cold on Tau phosphorylation may constitute a pathology-initiating trigger leading to neurodegeneration.

Presentation of infection in older patients--a prospective study

BACKGROUND

Traditional wisdom suggests that infections in older patients have atypical presentation, including blunted febrile response. Data are scarce.

DESIGN

We analyzed data from a prospectively collected database on presentation of infection in 4,308 patients, and compared the presentation of older patients (≥ 75 years) versus adults (< 75 years).

SETTINGS

Single tertiary medical center.

PARTICIPANTS

Patients admitted with suspected bacterial infection during 2002-2004 and 2010-2011.

MEASUREMENTS

We evaluated clinical presentation on day of admission, including vital signs and laboratory parameters.

RESULTS

No difference in fever values as a presenting sign of infection was found between older patients and adults (median fever 38.3°C, interquartile range [IQR] 37.4-39.0°C; and 38.4°C, IQR 37.3-39.0°C, respectively, P = 0.08). Median leukocyte count was significantly higher in older patients (median 11.60, IQR 8.30-15.72 in older patients; 10.84, 7.50-15.00 in adults, P < 0.001). Presentation with septic shock, acute renal failure, and reduced consciousness was significantly more common in older patients. These findings were also consistent in the subgroups of bacteremic patients and patients with microbiologically documented infection.

CONCLUSION

Elevated fever and leukocytosis were found to be at least equally common in older patients compared to younger adults as part of the presentation of infection.

Role of body temperature in diagnosing bacterial infection in nursing home residents

OBJECTIVES

To provide empirically based recommendations for incorporating body temperature into clinical decision-making regarding diagnosing infection in nursing home (NH) residents.

DESIGN

Retrospective.

SETTING

Twelve North Carolina NHs.

PARTICIPANTS

NH residents (N = 1,007) with 1,858 randomly selected antibiotic prescribing episodes.

MEASUREMENTS

Maximum prescription-day temperature plus the three most recent nonillness temperatures were recorded for each prescribing episode. Two empirically based definitions of fever were developed: population-based (population mean nonillness temperature plus 2 population standard deviations (SDs)) and individualized (individual mean nonillness temperature plus 2 population SDs). These definitions were used along with previously published fever criteria and Infectious Diseases Society of America (IDSA) criteria to determine how often each prescribing episode was associated with a "fever" according to each definition.

RESULTS

Mean population nonillness temperature was 97.7 ± 0.5 ºF. If "normal" were defined as less than 2 SDs above the mean, fever would be defined as any temperature above 98.7 ºF, and the previously published fever cutpoints and the IDSA criteria are 4.8 SDs above this mean. Between 30% and 32% of the 1,858 prescribing episodes examined were associated with temperatures more than 2 SDs above the population mean nonillness temperature, whereas only 10% to 11% of episodes met the previously published and IDSA fever definitions.

CONCLUSION

Clinicians should apply empirically based definitions to assess fever in NH residents. Furthermore, low fever prevalence in residents treated with antibiotics according to all definitions suggests that some prescribing may not be associated with acute bacterial infection.

Clinical and translational aspects of hypothermia in major trauma patients: from pathophysiology to prevention, prognosis and potential preservation

The human body strives at maintaining homeostasis within fairly tight regulated mechanisms that control vital regulators such as core body temperature, mechanisms of metabolism and endocrine function. While a wide range of medical conditions can influence thermoregulation the most common source of temperature loss in trauma patients includes: exposure (environmental, as well as cavitary), the administration of i.v. fluids, and anaesthesia/loss of shivering mechanisms, and blood loss per se. Loss of temperature can be classified either according to the aetiology (i.e. accidental/spontaneous versus trauma/haemorrhage-induced temperature loss), or according to an unintended, accidental induction in contrast to a medically intended therapeutic hypothermia. Hypothermia occurs infrequently (prevalence<10% of all injured), but more often (30-50%) in the severely injured. Hypothermia usually come together with and may aggravate acidosis and coagulopathy (the "lethal triad of trauma"), which again may be associated with a high mortality. However, recent studies disagree in the independent predictive role of hypothermia and mortality. Prevention of hypothermia is imperative through all phases of trauma care and must be an interest among all team members. Hypothermia in the trauma setting has attracted focus in the past from a pathophysiological, preventive and prognostic perspective; yet recent focus has shifted towards the potential for using hypothermia for pre-emptive and cellular protective purposes. This paper gives a brief update on some of the clinically relevant aspects of hypothermia in the injured patient.

Validating emergency department vital signs using a data quality engine for data warehouse

Background :

Vital signs in our emergency department information system were entered into free-text fields for heart rate, respiratory rate, blood pressure, temperature and oxygen saturation.

Objective :

We sought to convert these text entries into a more useful form, for research and QA purposes, upon entry into a data warehouse.

Methods :

We derived a series of rules and assigned quality scores to the transformed values, conforming to physiologic parameters for vital signs across the age range and spectrum of illness seen in the emergency department.

Results :

Validating these entries revealed that 98% of free-text data had perfect quality scores, conforming to established vital sign parameters. Average vital signs varied as expected by age. Degradations in quality scores were most commonly attributed logging temperature in Fahrenheit instead of Celsius; vital signs with this error could still be transformed for use. Errors occurred more frequently during periods of high triage, though error rates did not correlate with triage volume.

Conclusions :

In developing a method for importing free-text vital sign data from our emergency department information system, we now have a data warehouse with a broad array of quality-checked vital signs, permitting analysis and correlation with demographics and outcomes.

Assessment of body temperature measurement options

Assessment of body temperature is important for decisions in nursing care, medical diagnosis, treatment and the need of laboratory tests. The definition of normal body temperature as 37°C was established in the middle of the 19th century. Since then the technical design and the accuracy of thermometers has been much improved. Knowledge of physical influence on the individual body temperature, such as thermoregulation and hormones, are still not taken into consideration in body temperature assessment. It is time for a change; the unadjusted mode should be used, without adjusting to another site and the same site of measurement should be used as far as possible. Peripheral sites, such as the axillary and the forehead site, are not recommended as an assessment of core body temperature in adults. Frail elderly individuals might have a low normal body temperature and therefore be at risk of being assessed as non-febrile. As the ear site is close to the hypothalamus and quickly responds to changes in the set point temperature, it is a preferable and recommendable site for measurement of body temperature.

Relationships between brain and body temperature, clinical and imaging outcomes after ischemic stroke

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using (1)H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.

Comparison of three different thermometers in evaluating the body temperature of healthy young adult individuals

The aim of this study was to compare the measurement values obtained with a non-contact infrared thermometer, a tympanic thermometer and a chemical dot thermometer. The research population was composed of students studying in two departments of a university in Ankara. A total of 452 students who fit the inclusion criteria of the study and volunteered to participate were included in the sample. Body temperature measurements with different thermometers were performed by the same researcher at the same room temperature. Data were analyzed in a computerized environment by SPSS 15.0 statistical program pack and Bland-Altman graph. Mean age of healthy young adults participating in the study was 19.66 ± 0.94, and 55.1% of them were female. The agreement limits for non-contact infrared and chemical dot was between -1.30 and 0.32°C; for non-contact infrared and tympanic was between -1.26 and 0.13°C; and for chemical dot and tympanic -0.89 and 0.74°C. It was determined that, although the measurement values of the tympanic membrane and chemical dot thermometers conformed with each other, the conformity of the non-contact infrared thermometer was weak.

Temporal profile of body temperature in acute ischemic stroke: relation to stroke severity and outcome

Background

Pyrexia after stroke (temperature ≥37.5°C) is associated with poor prognosis, but information on timing of body temperature changes and relationship to stroke severity and subtypes varies.

Methods

We recruited patients with acute ischemic stroke, measured stroke severity, stroke subtype and recorded four-hourly tympanic (body) temperature readings from admission to 120 hours after stroke. We sought causes of pyrexia and measured functional outcome at 90 days. We systematically summarised all relevant previous studies.

Results

Amongst 44 patients (21 males, mean age 72 years SD 11) with median National Institute of Health Stroke Score (NIHSS) 7 (range 0–28), 14 had total anterior circulation strokes (TACS). On admission all patients, both TACS and non-TACS, were normothermic (median 36.3°C vs 36.5°C, p=0.382 respectively) at median 4 hours (interquartile range, IQR, 2–8) after stroke; admission temperature and NIHSS were not associated (r²=0.0, p=0.353). Peak temperature, occurring at 35.5 (IQR 19.0 to 53.8) hours after stroke, was higher in TACS (37.7°C) than non-TACS (37.1°C, p<0.001) and was associated with admission NIHSS (r²=0.20, p=0.002). Poor outcome (modified Rankin Scale ≥3) at 90 days was associated with higher admission (36.6°C vs. 36.2°C p=0.031) and peak (37.4°C vs. 37.0°C, p=0.016) temperatures. Sixteen (36%) patients became pyrexial, in seven (44%) of whom we found no cause other than the stroke.

Conclusions

Normothermia is usual within the first 4 hours of stroke. Peak temperature occurs at 1.5 to 2 days after stroke, and is related to stroke severity/subtype and more closely associated with poor outcome than admission temperature. Temperature-outcome associations after stroke are complex, but normothermia on admission should not preclude randomisation of patients into trials of therapeutic hypothermia.

Age-dependent changes in temperature regulation - a mini review

It is now well recognized that the body temperature of older men and women is lower than that of younger people and that their tolerance of thermal extremes is more limited. The regulation of body temperature does not depend on a single organ, but rather involves almost all the systems of the body, i.e. systems not exclusively dedicated to thermoregulatory functions such as the cardiovascular and respiratory systems. Since these deteriorate naturally with advancing age, the decrement in their functions resonates throughout all the bodily processes, including those that control body temperature. To the extent that the age-related changes in some of these, e.g. in the musculoskeletal system, can be slowed, or even prevented, by certain measures, e.g. fitness training, so can the decrements in thermoregulatory functions. Some deficits, however, are unavoidable, e.g. structural skin changes and metabolic alterations. These impact directly on the ability of the elderly to maintain thermal homeostasis, particularly when challenged by ambient thermal extremes. Since the maintenance of a relatively stable, optimal core temperature is one of the body's most important activities, its very survival can be threatened by these disorders. The present article describes the principal, age-associated changes in physiological functions that could affect the ability of seniors to maintain their body temperature when exposed to hot or cold environments.