Fatty degeneration in renal tubule epithelium in accidental hypothermia victims

The diagnosis "death due to hypothermia" is mainly based on circumstances and gross autopsy findings like frost erythema and gastric erosions. Up to now, there are no reliable histologic criteria available to confirm the diagnosis "death due to hypothermia." However, fatty changes of organs have been reported already in the literature as a histological finding contributing to the diagnosis "death due to hypothermia." To evaluate these reports, cases with well-documented hypothermia (study-group; n=83), cases with other causes of death (control-group; n=25) and additionally also seven cases with a past medical history of diabetes mellitus were investigated. Renal tissue autopsy samples were taken from both the left and the right kidney and investigated for signs of fatty degeneration within the renal tubule epithelium. The results were compared with regard to macroscopic signs of hypothermia (Wischnewski-ulcers, erythema), as reported in the autopsy protocols. The results lead to the conclusion, that fatty degeneration is a very reliable histologic diagnostic criterium in cases of hypothermia, comparable to the significance of Wischnewski-ulcers.     

Post-mortem investigation of calcium content in liver, heart, and skeletal muscle in accidental hypothermia cases

The identification of hypothermia as cause of the death was always quite problematic in the field of forensic medicine. The aim of the present study was to verify the determination of calcium content in post-mortem liver, heart, and skeletal muscle samples as the biochemical marker defining hypothermia as the cause of death. The study involved 43 autopsy cases in which the circumstances of death indicated the effects of overcooling. The control group consisted of material collected from the corpses of 30 persons who were not exposed to low temperatures but died due to technical injuries (n = 5), asphyxia (n = 6), intoxication with ethanol and other substances (n = 8), and acute myocardial infarction/ischemia (n = 11). The concentration of calcium in autopsy samples was determined applying flame atomic absorption spectroscopy. Our study showed no significant differences of calcium content in tissues of persons who died due to hypothermia, over those who died in normothermic conditions.     

MRI detects hemorrhages in the muscles of the back in hypothermia

Morphological findings in death due to hypothermia are variable and predominantly unspecific. Goal of this study was to check the usefulness of post-mortem cross-sectional imaging methods in the diagnosis of externally invisible findings in death due to hypothermia. Three consecutive forensic cases that died due to hypothermia were examined using post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) prior to autopsy. MSCT excluded traumatic skeletal and fatty tissue injury. Using MRI, it was possible to detect hemorrhages within the muscles of the back in all three cases, a so far unknown finding in death due to hypothermia. MRI also allowed the detection of hemorrhages in the iliopsoas muscles. Wishnewsky spots remained radiologically undetected using the present examination techniques. In conclusion, hemorrhages of the muscles of the back might serve as a new sign of death due to hypothermia; however, additional studies on their specificity are necessary. Post-mortem MRI is considered as a good diagnosing tool for muscular hemorrhages, with a great potential for examination and documentation.     

Hypothermia Secondary to Glioblastoma Multiforme? Autopsy Findings in Two Cases

Death due to accidental primary hypothermia in cold climates is relatively common, with previous case series reflecting this. In contrast, hypothermia‐related death as a result of an underlying medical cause, such as a brain tumor, is rare. The literature clearly illustrates a theoretical causal relationship between brain neoplasms and hypothermia through the infiltration of the hypothalamus; however, the number of reported cases is minimal. Two cases are presented where autopsy confirmed hypothermia as the cause of death with both cases revealing widespread glioblastoma multiforme in the brain. Both decedents were elderly with a number of comorbidities identified during autopsy that could explain death; however, hypothermia was deemed the most likely cause. It is proposed that both decedents died of hypothermia as a result of the tumor's effect on thermoregulation. These cases underline the importance of forensic pathologists to be aware of the relationship between brain tumors and hypothermia and to not dismiss death as being due to other disease processes.     

The influence of ethanol on the level of ketone bodies in hypothermia

Presently available possibilities of macro- and microscopic diagnosis of death from hypothermia are very limited as the changes observed are either weakly specific (ecchymoses in the mucous membrane of the stomach, histological features of haemorrhagic pancreatic necrosis, cardiomyocyte necrosis or decreased content of glycogen in hepatocytes) or represent only local action of low temperatures (frostbites, violet patches in the region of knees and elbows, red livores) and they may not be present in cases of death from cooling at environmental temperature close to zero or higher.The study evaluated the usefulness of acetoacetic acid (Ac-Ac), beta-hydroxybutyric acid (beta-HBA) and acetone determinations in blood, urine and vitreous humour for diagnosis of death from hypothermia. These three substances called ketone bodies, are easily assimilated energetic substrates that get oxidized preferentially before glucose and fatty acids. In hypoglycaemia (also hypothermia-induced one), the tissues dependent on glucose (e.g. the brain) cover most of their energetic needs from oxidation of these compounds.The analysis of 16 cases of death in circumstances suggesting hypothermia (mainly of the alcohol abusers) showed that the degree of ketosis was inversely proportional to the blood ethanol concentration. This relation may result from stimulation of insulin release and a decrease in the release of its antagonists by ethanol, as well as from inhibition of free fatty acid (FFA) beta-oxidation due to increase in the NADH/NAD ratio. So, the antiketonaemic effects of ethanol (together with its influence on the dilatation of the peripheral vessels and inhibition of shivering thermogenesis by muscle relaxation), explain increased sensitivity of intoxicated persons to low temperatures.     

Postmortem Diagnosis of Fatal Hypothermia by Fourier Transform Infrared Spectroscopic Analysis of Edema Fluid in Formalin-Fixed,Paraffin-Embedded Lung Tissues

The goal of this study was to investigate whether pulmonary edema could become a specific diagnostic marker for fatal hypothermia using Fourier transform infrared (FTIR) spectroscopy in combination with chemometrics. The spectral profile analysis indicated that hypothermia fatalities associated with pulmonary edema fluid contained more β-sheet protein conformational structures than the control causes of death, which included sudden cardiac death, brain injury, cerebrovascular disease, mechanical asphyxiation, intoxication, and drowning. Subsequently, the results of principal component analysis (PCA) further revealed that the content of β-sheet protein conformational structures in the pulmonary edema fluid was the main discriminatory marker between fatal hypothermia and the other causes of death. Ultimately, a robust postmortem diagnostic model for fatal hypothermia using a partial least-squares discriminant analysis (PLS-DA) algorithm was constructed. Pulmonary edema fluid spectra collected from eight new forensic autopsy cases that did not participate in the construction of the diagnostic model were predicted using the model. The results showed the causes of death of all these eight cases were correctly classified. In conclusion, this preliminary study demonstrates that FTIR spectroscopy in combination with chemometrics could be a promising approach for the postmortem diagnosis of fatal hypothermia.     

Wischnewski revisited. The diagnostic value of gastric mucosal ulcers in hypothermic deaths

Hypothermia is defined as a subnormal body temperature. In this article, hypothermia refers to the loss of core temperature from exposure. When death results from hypothermia, a series of gastric mucosal erosions known as "Wischnewski ulcers" (1) frequently occur. In examining case material of the Onondaga County Medical Examiner's Office, a characteristic pattern of these ulcerations was seen that was indicative of severe physiologic stress and/or hypothermia. While not pathognomonic of hypothermia, the incidence of the erosions in a specific pattern has been closely associated with deaths in which hypothermia played a significant role. In hypothermia, the erosions, usually shallow and approximately 0.1-0.5 cm in diameter, are set in lines with roughly equidistant spacing, thereby forming a pattern of rectangles with the corners marked by the ulcerations.     

Death from Hypothermia during a Training Course under “Extreme Conditions”: Related to Two Cases

Death from hypothermia following exhaustion or from various complicated pathologies is no longer a frequent cause of death among combat troops. During a training course under “extreme conditions” in the French Alps, two young African officers died. Confronted with these two clinically confirmed cases of hypothermia, the unknown anatomopathological and biological specificities associated with death from hypothermia were highlighted. In these typical and clinically confirmed cases of death from subacute exhaustion hypothermia, none of the signs revealed by the autopsy were specific. Although some recent publications have addressed the utility of postmortem biochemical markers when establishing a diagnosis, with no anamnesis, with no knowledge or analysis of the circumstances of death, and without an in situ examination of the body, it appears difficult, if not impossible, to confirm that death was caused by hypothermia.     

Changes in skeletal muscles in death caused by hypothermia

The review of 32 deaths resulting from hypothermia yielded mostly the common pathological findings as bright red livores, haemolytic frost marks of the skin and Wichnewski erosions of the gastric mucosa. In addition the muscle system of the body core (musc. ileopsoas) showed hemorrhages and histologically necrosis of its fibres in form of segmental and discoid sarcoplasmatic alteration. These changes are a quite specific sign of death due to hypothermia, as far as mechanical injury can be excluded. For best result however a special autopsy technique and an appropriate histological staining are advisable.     

Analysis of violent deaths of mountaineers and tourists at high altitudes

The principal causes of violent death of mountaineers and tourists at high altitudes are described with special reference to the character of injuries to the skin, soft tissues, bones, and internal organs inflicted by mechanical impacts. The cases of violent death from other factors are described, such as general hypothermia, atmospheric electricity, compression and obturation asphyxia of mountaineers and tourists who died in the epicenter of an avalanche. The additional criteria for forensic medical diagnostics of violent death of montaineers and tourists at high altitudes are considered.     

The expression of excitatory amino acid transporter 2 (EAAT2) in forensic autopsy cases

Glutamate is the major excitatory neurotransmitter and the greater part of this amino acid is removed from the synaptic cleft by excitatory amino acid transporter 2 (EAAT2) located on perisynaptic astrocytes. Recently, it was reported that the EAAT2 protein content changed in rats following forebrain ischemia and administration of methamphetamine. We planned to demonstrate the immunohistochemical distribution of EAAT2 in the human brain and discuss the significance of its pathophysiological roles. Thirty-two cases were used from forensic autopsies. The tissues were sampled from the cerebral cortex, striatum and hippocampus. The distribution of EAAT2 was difficult to identify in cases of electrical fatalities. However, continuous and extensive staining of EAAT2 was observed in cases of death from hypothermia. In almost all asphyxia death, we were able to observe a weak stain of EAAT2. In case of solvent abuse, EAAT2 staining was continuous and extensive as in the cases of hypothermia, and patchy negative zones were mixed. This study clearly showed the differences in EAAT2 localization according to the cause of death. These findings suggested that the differences in EAAT2 staining depended on the cause and course (pathophysiological conditions) of death.     

青壮年猝死综合征心肌细胞内Cx43的表达

目的观察连接蛋白43（Cx43）在青壮年猝死综合征（SMDS）者心肌细胞的表达,并探讨其法医学意义。方法筛选法医尸检案例45例,其中SMDS组、冠心病猝死组及对照组各15例。采用免疫组织化学和图像分析技术对不同组别Cx43蛋白在心肌细胞内的表达进行阳性单位（PU）定量检测,分析Cx43蛋白在各组表达的差异。所得数据进行统计学分析。结果 SMDS组心肌Cx43染色明显减弱,阳性着色条带分布不均、深浅不一,有的呈散在颗粒状;冠心病猝死组亦见类似变化;对照组未见明显变化。经统计分析发现,3组心肌细胞内Cx43表达的PU值存在显著性差异（P〈0.05）。结论 SMDS死前存在心肌缺血及心电紊乱,应属心性猝死范畴。     

Hypothermia-related Deaths: A 10-year Retrospective Study of Two Major Metropolitan Cities in the United States*

Hypothermia-related deaths affect vulnerable populations and are preventable. They account for the vast majority of weather-related deaths in the United States. The postmortem diagnosis of hypothermia can be challenging, as there are no pathognomonic signs. The electronic databases of the New York City Office of Chief Medical Examiner and Harris County Institute of Forensic Sciences were searched for all fatalities where the primary cause of death included hypothermia, between January 2009 and July 2019. There were 139 hypothermia deaths in New York City (NYC) with an average annualized rate of 1.7 per million. During this same time, there were 50 hypothermia deaths in Houston with an average annualized rate of 2.4 per million. Males were more likely to die of hypothermia compared to females in both cities. The rate ratio (RR) in NYC was 3.55 (95% CI 2.40, 5.25), while the RR in Houston was 2.83 (95% CI 1.50, 5.32). Age- and sex-specific standardized hypothermia mortality rates were 18.2 (95% CI 15.1, 21.2) per million in NYC and 30.1 (95% CI 21.7, 38.6) per million in Houston. The comparative hypothermia death ratio was 1.66 (95% CI 1.19, 2.30), indicating hypothermia mortality in Houston was 66% higher than in NYC. There was no correlation between zip code poverty rates and hypothermia-related deaths. The most consistent autopsy finding was Wischnewski spots (56.6%), and ethanol was the most common toxicological finding (36.5%). Local agencies can use this data to target these higher-risk populations and offer appropriate interventions to try to prevent these deaths.     

Immunohistochemical study of fibronectin for postmortem diagnosis of early myocardial infarction

The postmortem diagnosis of early myocardial infarction has been a puzzling problem in forensic practice. In the present study, an immunohistochemical study of fibronectin (FN) was performed for the first time on 34 autopsy hearts to determine early myocardial infarction with streptavidin/biotin/peroxidase technique. Five cases of definite myocardial infarction showed positive FN staining of cardiomyocytes; of 18 cases where early myocardial infarction was suspected, positive FN staining of cardiomyocytes was found in 15 cases, but no such staining was seen in 11 non-cardiac death controls. The results led to the conclusion that positive FN staining in cardiomyocytes is a reliable marker of acute myocardial infarction and could be used as a new, sensitive method for the postmortem diagnosis of early myocardial infarction. It is worth noting that all cases in this study were autopsied between 8 h and 4 days after death and 5 cases had been fixed in 10% formalin for over 10 years. FN immunohistochemistry still gave satisfactory results in those cases. It seemed that FN was not affected by postmortem autolysis and formalin-fixation and could be used in routine forensic practice, especially for retrospective analysis of cases.     

冠心病猝死心肌纤维连接蛋白免疫组化染色观察

目的研究纤维连接蛋白（FN）免疫组化染色对冠心病猝死（SCD）的病理学诊断价值。方法用兔抗人FN多克隆抗体对人SCD心肌、颅脑损伤和病毒性心肌炎致死者心肌进行FN-SP免疫组化染色观察，用图像分析处理系统对FN免疫组织化学染色阳性反应产物面积定量，所得数据进行统计分析。结果SCD组16例心肌组织内FN大量沉积；颅脑损伤致死组心肌细胞内FN染色阴性，病毒性心肌炎致死组部分心肌细胞内FN阳性；3组心肌细胞内的阳性反应面积存在显著性差异（P〈0．05）。冠心病猝死组阳性反应面积（μm^2）为54143．28±8474．92；颅脑损伤致组阳性反应面积（μm^2）为527．99±105．04；病毒性心肌炎组阳性反应面积（μm^2）为5483．53±1219．91。结论冠心病猝死者心肌FN免疫组化检测可为死因诊断提供可靠依据。     

A Comparison of Hypothermic Deaths in South Australia and Sweden

Case files from Forensic Science South Australia and the Swedish National Forensic Database were reviewed over a 6‐year period from 2006 to 2011 for cases where hypothermia either caused, or significantly contributed to, death. Data were analyzed for age, sex, time of year/season, place of discovery, circumstances of death, and underlying medical conditions. Despite the considerable demographic, geographic, and climatological differences, hypothermic deaths occurred at very similar rates in South Australia (3.9/100,000) and Sweden (3.3/100,000). Deaths from hypothermia in South Australia occurred predominantly indoors at home addresses, involving elderly females with multiple underlying illnesses and limited outside contacts. In contrast, Swedish hypothermic deaths generally occurred outdoors and involved middle‐aged elderly males. These data show that hypothermia may be a risk in warmer climates particularly for elderly, socially isolated individuals.     

青壮年猝死综合征心肌细胞内纤维连接蛋白免疫组化观察初探

本文应用免疫组化ＬＳＡＢ法首次对５例青壮年碎死综合征和１１例非心性死亡对照组进行心肌细胞内纤维连接蛋白的研究。发现青壮年猝死综合征５例中有３例心肌细胞内纤维连接蛋白阳性。１１例非心性死、对照组心肌细胞内纤维连接蛋白均呈阴性。说明上述３例青壮年猝死综合征的心肌细胞已发生不可逆损伤，实属早期心肌梗死。该研究为青壮年猝死综合征的死因研究提供了一个新的方向和手段。     

早期心肌梗死心肌细胞内纤维连接蛋白的免疫组化观察

应用免疫组化LSAB法，对34例尸检心脏标本，进行心肌细胞内纤维连接蛋白用于早期心肌梗死死后诊断的研究。其中尸检及组织学证实心肌梗死5例，其心肌细胞内纤维连接蛋白均呈阳性。冠状动脉有硬化或冠状动脉口狭窄的可疑心肌梗死18例，其中15例心肌细胞内纤维连接蛋白阳性。非心性死亡对照组11例，心肌细胞内纤维连接蛋白均呈阴性。实验表明，心肌细胞内纤维连接蛋白免疫组化观察在急性心肌梗死，尤其是早期心肌梗死死后诊断上具有重要价值，为早期心肌梗死的死后诊断提供了一个实用方法。     

An unusual case of accidental hypothermia due to cold water immersion

Accidental deaths due to hypothermia most commonly result from exposure to low environmental temperature. Generally, a cold climatic condition is present in a severe environmental setting. A case report is presented of a 58-year-old man who died from accidental hypothermia associated with immersion in cold water while on a farm during warm weather. The importance of an adequate death scene investigation is discussed.     

Disappearance of ethyl glucuronide during heavy putrefaction

Adrenocorticotropic hormone (ACTH) is involved in systemic reactions to stress. The aim of the present study was a comprehensive analysis of serum and cerebrospinal fluid (CSF) levels of ACTH, and the pituitary immunohistochemistry with special regard to fatal hypothermia in routine forensic autopsy cases (n=162: 5-97 years of age; 114 males and 48 females; 4 h to 3 days postmortem, median, 19.2 h). The ACTH concentrations were independent of the postmortem time, gender, or age of the subjects. The serum ACTH level was similar to the clinical reference value for sharp instrument injury, fire fatality, and hypothermia, but was lower in other groups including hyperthermia, in particular for asphyxia and poisoning. The CSF level was usually much higher than the serum level, but was significantly lower for hypothermia and hyperthermia than in other groups (p<0.01). The rate of ACTH-immunopositivity in the anterior pituitary was low in cases of fatal hypothermia and hyperthermia, while it was high in cases of blunt injury, fire fatality, and acute ischemic heart disease. These observations showed that ACTH levels in the serum and CSF depended on the cause of death. The serum level was maintained despite a low CSF level and pituitary immunopositivity for fatal hypothermia, while the serum and CSF levels as well as pituitary immunopositivity were decreased for hyperthermia.