Hyperthermia and postmortem biochemical investigations

The Value of Myocardium and Kidney Histopathological and Immunohistochemical Findings in Accidental Hypothermia-Related Fatalities

Background and Objectives: The post-mortem diagnosis of hypothermia is challenging in forensics. The aim of our study was to detect the kidney and heart histopathological changes that occurred in a group of hypothermia-related fatalities. Materials and Methods: The cohort included 107 cases identified in the database of our department between 2007 and 2021, which have been associated with extreme cold stress. Demographic and clinicopathological data were collected from the medico-legal reports. Archived tissue samples were evaluated to identify the histopathological features, in routine haematoxylin-eosin (H&E), Periodic acid-Schiff (PAS), and Masson's trichrome stainings, while cardiac sirtuin1 (SIRT1) and renal ubiquitin (Ub) immunostaining have been performed. Results: The majority of cases exposed to low temperatures were males (76%) from rural regions (68.2%) during the cold season. Paradoxical undressing was documented in 9.3% of cases. The common comorbidities included alcoholism (50.5%), neuropsychiatric diseases (10.3%), diabetes mellitus (3.7%), and lung tuberculosis (4.7%). The microscopic heart exam revealed areas of myocardial degeneration (100%), contraction bands (95.3%), fatty change (13.1%) and focal wavy contractile myocardial cells. Basal vacuolisation of renal tubular epithelial cells (Armanni-Ebstein lesions) (21.5%), focal tubular necrosis (7.5%), tubular renal cysts (7.5%), interstitial haemorrhages (5.6%), diabetic kidney disease (3.7%), background benign nephroangiosclerosis (42.1%), variable thickening of tubules and corpuscles basement membranes, capsular space amorphous material, and intratubular casts were identified in kidney tissue samples. Myocardial cells displayed SIRT1 weak expression, with a loss of immunopositivity correlated with areas with contraction bands, while a variable Ub expression was observed in renal corpuscles capsules, proximal, distal, and collecting renal tubules, Henle's loops, urothelium, and intratubular casts. Conclusions: In the context of the current concept that death associated with hypothermia is still a diagnosis of exclusion, our findings suggest that the microscopic exam provides relevant data that support the diagnosis of hypothermia-related fatalities in appropriate circumstances of death. A deeper insight into the histopathologic findings in hypothermic patients may lead to new therapeutic approaches in these cases.

Heat-Related Illness in Emergency and Critical Care: Recommendations for Recognition and Management with Medico-Legal Considerations

Hyperthermia is an internal body temperature increase above 40.5 °C; normally internal body temperature is kept constant through natural homeostatic mechanisms. Heat-related illnesses occur due to exposure to high environmental temperatures in conditions in which an organism is unable to maintain adequate homeostasis. This can happen, for example, when the organism is unable to dissipate heat adequately. Heat dissipation occurs through evaporation, conduction, convection, and radiation. Heat disease exhibits a continuum of signs and symptoms ranging from minor to major clinical pictures. Minor clinical pictures include cramps, syncope, edema, tetany, and exhaustion. Major clinical pictures include heatstroke and life-threatening heat stroke and typically are expressed in the presence of an extremely high body temperature. There are also some categories of people at greater risk of developing these diseases, due to exposure in particular geographic areas (e.g., hot humid environments), to unchangeable predisposing conditions (e.g., advanced age, young age (i.e., children), diabetes, skin disease with reduced sweating), to modifiable risk factors (e.g., alcoholism, excessive exercise, infections), to partially modifiable risk factors (obesity), to certain types of professional activity (e.g., athletes, military personnel, and outdoor laborers) or to the effects of drug treatment (e.g., beta-blockers, anticholinergics, diuretics). Heat-related illness is largely preventable.

Attenuated total reflection-Fourier transform infrared spectroscopy: a universal analytical technique with promising applications in forensic analyses

Contemporary criminal investigations are based on the statements made by the victim and the eyewitnesses. They also rely on the physical evidences found in the crime scene. These evidences, and more particularly biological ones, have a great judicial value in the courtroom. They are usually used to revoke the suspect’s allegations and confirm or refute the statements made by the victim and the witnesses. Stains of body fluids are biological evidences highly sought by forensic investigators. In many criminal cases, the success of the investigation relies on the correct identification and classification of these stains. Therefore, the adoption of reliable and accurate forensic analytical methods seems to be of vital importance to attain this objective. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) is a modern and universal analytical technique capable of fingerprint recognition of the analyte using minimal amount of the test sample. The current systematic review aims to through light on the fundamentals of this technique and to illustrate its wide range of applications in forensic investigations. ATR-FTIR is a nondestructive technique which has demonstrated an exceptional efficiency in detecting, identifying and discriminating between stains of various types of body fluids usually encountered in crime scenes. The ATR-FTIR spectral data generated from bloodstains can be used to deduce a wealth of information related to the donor species, age, gender, and race. These data can also be exploited to discriminate between stains of different types of bloods including menstrual and peripheral bloods. In addition, ATR-FTIR has a great utility in the postmortem investigations. More particularly, in estimating the postmortem interval and diagnosing death caused by extreme weather conditions. It is also useful in diagnosing some ambiguous death causes such as fatal anaphylactic shock and diabetic ketoacidosis.

Classic and exertional heatstroke

In the past two decades, record-breaking heatwaves have caused an increasing number of heat-related deaths, including heatstroke, globally. Heatstroke is a heat illness characterized by the rapid rise of core body temperature above 40 °C and central nervous system dysfunction. It is categorized as classic when it results from passive exposure to extreme environmental heat and as exertional when it develops during strenuous exercise. Classic heatstroke occurs in epidemic form and contributes to 9-37% of heat-related fatalities during heatwaves. Exertional heatstroke sporadically affects predominantly young and healthy individuals. Under intensive care, mortality reaches 26.5% and 63.2% in exertional and classic heatstroke, respectively. Pathological studies disclose endothelial cell injury, inflammation, widespread thrombosis and bleeding in most organs. Survivors of heatstroke may experience long-term neurological and cardiovascular complications with a persistent risk of death. No specific therapy other than rapid cooling is available. Physiological and morphological factors contribute to the susceptibility to heatstroke. Future research should identify genetic factors that further describe individual heat illness risk and form the basis of precision-based public health response. Prioritizing research towards fundamental mechanism and diagnostic biomarker discovery is crucial for the design of specific management approaches.

Fatal pediatric hyperthermia: A forensic review

This paper examines a pediatric hyperthermia homicide in which the decedent was placed into a room with only a diaper on and left unattended overnight. There were no furnishings in the room except for a 1500-W space heater and a stroller. The following morning, emergency personnel were summoned to the residence. A caretaker said the decedent playing normally 5 min before making the 911 call. The decedent's initial rectal temperature was 42.2°C. Law enforcement asked how long the child had to be exposed to a high temperature in order to induce fatal hyperthermia in an empty bedroom. The scene was reconstructed using the child's residence and the same heater. Environmental data were gathered over a 16-h period. The thermal parameters of the room and environment were analyzed using a lumped-element thermal model. These parameters were then fed into an adapted Gagge's two-node model of human thermal regulation, which provided a time-window of exposure necessary to elicit hyperthermia, which in this case, depending on certain variables, ranged from 45 min to 4 h.

Hypothermia causes platelet activation in the human spleen

BACKGROUND

Accidental hypothermia results in various dysfunctions in the human body. Additionally, coagulation disorder can lead to a life-threatening condition. We previously demonstrated that platelets stored in the spleen were activated and thus triggered coagulation disorder in a mouse model of hypothermia. In the present study, we wanted to investigate if this phenomenon in mice also occurs in humans as a reaction to hypothermia.

METHODS

We analyzed splenic tissue collected from 22 deceased subjects who have died from hypothermia. These samples were compared with 22 control cases not exposed to cold environment. We performed immunohistochemical staining for CD61 (a marker of all platelets) and CD62P (a marker of activated platelets). We also evaluated the morphology of platelets in the spleen with scanning electron microscopy.

RESULTS

Immunohistochemical analysis revealed no significant changes in the amounts of CD61-positive platelets between the hypothermia and control cases. However, the hypothermia cases contained abundant CD62P-positive platelets compared with those of the control cases. Immunohistochemical analysis also revealed that the activated platelets formed aggregates and adhered to splenic sinusoidal endothelial cells in the hypothermia cases. However, we observed no significant fibrin formation around the activated platelets.

CONCLUSIONS

Hypothermia resulted in splenic platelet activation, which may be used as a postmortem marker of hypothermia. The release of activated platelets from the spleen into to circulation upon rewarming may promote coagulation disturbances.

Long-lasting agony and failure to provide assistance in a case of mixed methadone-prescription drugs acute intoxication

Methadone overdoses are usually considered "slow" and avoidable deaths. Despite being frequently witnessed, the type and duration of the agonal time are rarely documented and challenging to be reconstructed. Here we report a case in which a young male was found dead in a parked car, shortly after discharge from a compulsory psychiatric treatment. Death scene investigation, clinical records collection, analysis of video recordings from surveillance cameras and private videos, post-mortem examination, GC-MS and LC-MS/MS toxicological analyses were performed and allowed to assess an acute fatal intoxication by methadone and prescription drugs. The case here-in reported is a rare example of a witnessed and recorded prolonged agonal phase due to methadone and drug intoxication, which lasted at least 12 hours. The loss of consciousness and a worsening pattern of respiratory depression, including gasping, were reported by the friends of the victim, but no one called for help, arising the suspect of failure to provide assistance. The possibility of a long-lasting agony with respiratory gasping should be considered in the evaluation of similar intoxication cases.

Evaluation of cytokines and structural proteins to analyze the pathology of febrile central nervous system disease

This study was designed to examine the pathophysiological differences in interleukin (IL) and structural protein levels between central nervous system (CNS) disorders associated with heat stroke and CNS stimulants. We measured the concentrations of IL-6, IL-8, neuron-specific enolase (NSE), and myelin basic protein (MBP) in blood and cerebrospinal fluid (CSF) from 87 autopsy cases. In addition, to examine changes in each marker, we cultured nerve cells at 40 °C as a heat stroke model and administered 4-aminopyridine and ephedrine in cultured cells as a CNS stimulant model. IL-6 levels in blood and CSF were significantly higher in the stimulant compared with the heat stroke group. IL-8 levels in blood and CSF were relatively high in the stimulant, heat stroke, and psychotropic addiction groups. NSE levels in blood were high in the stimulant and heat stroke groups, while those in CSF were significantly higher in the heat stroke group. MBP levels in blood were markedly higher in the stimulant and heat stroke groups, but no differences were seen in CSF. Compared with the CNS stimulant model, the heat stroke model with cultured human nerve cells showed high values for each marker. The results of the autopsy and laboratory tests in the present cases and those of cultured cell experiments indicated that CNS disorders caused by CNS stimulants such as amphetamines led to changes in IL-6 as an immune response, which suggests that IL-8 may help protect nerve cells in cases involving heat stroke and stimulants.

The Estimation of Postmortem Serum Urea via the Ultrafiltration of Hemolyzed Blood

Postmortem serum urea has been demonstrated as an objective indicator for the forensic diagnosis of cause of death. However, samples used in postmortem biochemical analysis are always affected by hemolysis. To investigate whether hemolysis affects the biochemical analysis of urea and to explore the feasibility of using ultrafiltration to process hemolyzed blood samples, three different levels of hemolyzed blood samples were used to assess the influence of hemolysis on postmortem biochemical analysis of urea, and two ultrafiltration methods were used to process the hemolyzed blood samples. Bias% was used to assess the interference of hemolysis. Our results showed that heavy hemolysis had a significant influence on the biochemical analysis of urea. Both ultrafiltration methods in the present study could significantly reduce the interference of hemolysis, with the |bias%| of methods A and B decreasing from 69.74% ± 99.14% to 12.18% ± 7.23% and 10.77% ± 8.09%, respectively, compared to the original serum. After regression correction, there was no significant difference between the urea concentration in the ultrafiltrates of the two ultrafiltration methods and that in the original serum, which suggested that the postmortem serum urea concentration could be estimated by the corrected urea concentration in the ultrafiltrate. The current study also provided possible pretreatment methods for postmortem biochemical analysis of other biomarkers in hemolyzed blood samples of forensic practice.

RHDV2 epidemic in UK pet rabbits. Part 1: clinical features, gross post mortem and histopathological findings

Objectives

To report clinical features, gross post mortem and histopathological findings from an investigation into sudden or unexpected death in rabbits that was undertaken during an outbreak of rabbit haemorrhagic disease.

Materials and Methods

Using a standard protocol, veterinarians were invited to submit case histories and results of their post mortem examination of pet rabbits that died unexpectedly. Histopathological examination of heart, lungs, liver, spleen and kidney samples was collated with macroscopic appearance and clinical details.

Results

Hepatocellular necrosis, characteristic of rabbit haemorrhagic disease, was observed in 185 of 300 (62%) submissions, often accompanied by glomerular thrombosis and changes in other organs. Evidence of rabbit haemorrhagic disease was not apparent on histopathology in 113 of 300 (38%) rabbits. Gross post mortem examination by veterinary practitioners did not always reflect reported histopathological changes. No macroscopic abnormalities were seen in 78/185 (42%) of rabbit haemorrhagic disease cases. Rapid death and death of other rabbits in the household were common features of rabbit haemorrhagic disease. Ante mortem clinical signs included anorexia, collapse, lethargy, seizures, icterus, bleeding from the mouth, dyspnoea, hypothermia, pyrexia, bradycardia or poor blood clotting.

Clinical Importance

Rabbit haemorrhagic disease can be suspected from a history of sudden death, especially if multiple rabbits are affected. There is not always macroscopic evidence of the disease but histopathology is useful to support or refute a diagnosis of rabbit haemorrhagic disease and provide information about other causes of death.

Fatal α-PVP and amphetamine poisoning during a sauna and autoerotic practices

We describe the sudden death of a middle-aged man while having a sauna under the influence of α-pyrrolidinovalerophenone (α-PVP) (PM blood concentration: 0.8 mg/L), amphetamine (0.34 mg/L), and other drugs (buprenorphine, benzodiazepines), and engaging in solitary sexual activities. The drugs’ effects on the cardio-circulatory system and on body thermoregulation combined with the high temperatures are likely to have been central mechanisms leading to death. The high levels of adrenaline triggered by sexual arousal and the respiratory depression caused by buprenorphine, in association with benzodiazepines, may have also contributed to his death. This previously unreported type of accidental autoerotic death illustrates the risk of using amphetamine-like sympathomimetic drugs (e.g. cathinone derivates) in hot environments such as a sauna, and during sexual activities therein.

Postmortem diagnosis of fatal hypothermia/hyperthermia by spectrochemical analysis of plasma

Postmortem diagnosis of extreme-weather-related deaths is a challenging forensic task. Here, we present a state-of-the-art study that employed attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy in combination with Chemometrics for postmortem diagnosis of fatal hypothermia/hyperthermia by biochemical investigation of plasma in rats. The results of principal component analysis (PCA) and spectral analysis revealed that plasma samples from the fatal hypothermia, fatal hyperthermia, and control groups, are substantially different from each other based on the spectral variations associated with the lipid, carbohydrate and nucleic acid components. Two partial least squares-discriminant analysis (PLS-DA) classification models (hypothermia-nonhypothermia and hyperthermia-nonhyperthermia binary models) with a 100% accuracy rate were constructed. Subsequently, internal cross-validation was performed to assess the robustness of these two models, which resulted in 98.1 and 100% accuracy. Ultimately, classification predictions of 42 unknown plasma samples were performed by these two models, and both models achieved 100% accuracy. Additionally, our results demonstrated that hemolysis and postmortem hypothermic/hyperthermic effects did not weaken the prediction ability of these two classification models. In summary, this work demonstrates ATR-FTIR spectroscopy's great potential for postmortem diagnosis of fatal hypothermia/hyperthermia.

Biochemical detection of fatal hypothermia and hyperthermia in affected rat hypothalamus tissues by Fourier transform infrared spectroscopy

It is difficult to determinate the cause of death from exposure to fatal hypothermia and hyperthermia in forensic casework. Here, we present a state-of-the-art study that employs Fourier-transform infrared (FTIR) spectroscopy to investigate the hypothalamus tissues of fatal hypothermic, fatal hyperthermic and normothermic rats to determine forensically significant biomarkers related to fatal hypothermia and hyperthermia. Our results revealed that the spectral variations in the lipid, protein, carbohydrate and nucleic acid components are highly different for hypothalamuses after exposure to fatal hypothermic, fatal hyperthermic and normothermic conditions. In comparison with the normothermia group, the fatal hypothermia and hyperthermia groups contained higher total lipid amounts but were lower in unsaturated lipids. Additionally, their cell membranes were found to have less motional freedom. Among these three groups, the fatal hyperthermia group contained the lowest total proteins and carbohydrates and the highest aggregated and dysfunctional proteins, while the fatal hypothermia group contained the highest level of nucleic acids. In conclusion, this study demonstrates that FTIR spectroscopy has the potential to become a reliable method for the biochemical characterization of fatal hypothermia and hyperthermia hypothalamus tissues, and this could be used as a postmortem diagnostic feature in fatal hypothermia and hyperthermia deaths.

Possible fatal hyperthermia involving drug abuse in a vehicle: case series

Major interplaying causes of heat stroke (HS) and fatal hyperthermia are climate, physical activity, artificial extreme ambient temperatures, confinement in a small compartment, and effects of drugs and chemicals, combined with predispositions and complications. A common and unfortunate cause of HS is vehicular hyperthermia (VH) death. Hyperthermia in a vehicle is a type of environmental thermal disorder, involving victim's susceptibility, confinement with restraint, and possible influences of drugs and poisons, including exhaust gas containing complex fumes, carbon dioxide and monoxide. Whereas VH typically occurs when babies or young children are being left unattended in parked vehicles in direct sunlight, it has been reported only anecdotally for adult subjects. Three cases of adult fatal VH will be herein presented. In each presented case the corpse was found enclosed in a vehicle on spring/summer days. During crime scene investigation (CSI) psychoactive substances were found near to the corpses leading to the suspect of a suicidal fatal drug intoxication. Basing on this misleading suspect in Case 2 and 3 a forensic expert was not charged for the CSI and a fatal VH was not suspected nor properly investigated. Later, a comprehensive autopsy, including biochemical and toxicological analyses, excluded a death related to natural causes, fatal intoxications, ketoacidosis and traumas. On the other hand, the reconstruction of the temperature, the humidity, the heat index and the related risk of HS allowed the diagnosis of fatal VH in all the reported cases. In particular, death occurred because of the long-lasting stay into a hot parked vehicle which was facilitated from self-administration of psychoactive drugs with related neuro-depression. This case series confirms that a comprehensive CSI followed by an autopsy including histology, biochemical and toxicological analysis remains mandatory in cases of forensic interest, as well as when a corpse is found enclosed in a vehicle. Anyway, sometimes the diagnosis of heat-related fatalities remains a medley of investigative and medicolegal observations.

Increased cerebral expressions of MMPs, CLDN5, OCLN, ZO1 and AQPs are associated with brain edema following fatal heat stroke

Human brain samples were collected from 46 autopsy cases, including 23 fatal heat stroke cases and 23 age-matched controls. Nine candidate reference genes (PES1, POLR2A, IPO8, HMBS, SDHA, GAPDH, UBC, B2M, ACTB) were evaluated in the cerebral cortex of 10 forensic autopsy cases (5 heat stroke and 5 controls), using the geNorm module in qBase^plus software. SDHA, POLR2A, IPO8 and HMBS were identified as the most stable reference genes. Using these validated reference genes, mRNA expressions of Matrix metalloproteinases (MMPs, MMP2 and MMP9), Claudin5 (CLDN5), Occludin (OCLN), Zona occludens protein-1 (ZO1) and Aquaporins (AQPs, AQP1 and AQP4) in the cerebral cortex were examined. Relative mRNA quantification using Taqman real-time PCR assay demonstrated increased calibrated normalized relative quantity (CNRQ) values of MMP9, CLDN5, OCLN, ZO1 and AQP4 in heat stroke cases. Heat stroke cases showed an increase in brain water content, which was found to be positively correlated with MMP9, OCLN, ZO1 and CLDN5 mRNA. When using one conventional reference gene (GAPDH or ACTB) for normalization, no difference was detected between heat stroke and controls. In immunostaining, only AQP4 showed more intense staining in most heat stroke cases. The present study, for the first time, reports increased cerebral MMP9, CLDN5, OCLN, ZO1 and AQP4 in heat stroke and suggest a crucial role of reference gene selection when using postmortem human tissues.

Electric fences and accidental death

Deaths which occur in association with agricultural electric fences are very rare. In fact, electric fences have undoubtedly saved numerous human and animal lives by safely and reliably keeping livestock confined to their fields and enclosures and thus preventing motor vehicle incidents when livestock get onto roads and highways. Accidental and intentional human contact with electric fences occurs regularly and causes little more than transient discomfort, however, on exceptional occasions, contact with electric fences appears to be directly related to the death of the individual. The precise pathophysiological cause of these deaths is unclear. We present two cases of deaths associated with electric fences, discuss the possible pathophysiological mechanisms in these cases, and suggest a universal approach to the medico-legal investigation and documentation of these deaths.

Exposures to conducted electrical weapons (including TASER® devices): how many and for how long are acceptable?

TASER(®) conducted electrical weapons (CEWs) are an important law-enforcement tool. The purposes of this study are a) to review recent literature regarding potential pathophysiological responses to applications of CEWs, and other related issues and b) to evaluate whether enough data exist to determine the acceptability of longer-duration (or repeated) exposures. This is a narrative review, using a multidisciplinary approach of analyzing reports from physiological, legal-medical, and police-strategy literature sources. In general, short-duration exposures to CEWs result in limited effects. Longer-duration or repeated exposures may be utilized with caution, although there are currently not enough data to determine the acceptability of all types of exposures. Data examined in the literature have inherent limitations. Appropriateness of specific types of CEW usage may be determined by individual police agencies, applying risk/benefit analyses unique to each organization. While more research is recommended, initial concepts of potential future long-duration or repeated CEW applications are presented.