Basal Subnuclear Vacuolization, Armanni-Ebstein Lesions, Wischnewsky Lesions, and Elevated Vitreous Glucose and β-Hydroxybuyrate: Is It Hypothermia, Diabetic Ketoacidosis, or Both?

Prominent black esophagus, Wischnewsky spots, and black duodenum in a fatal hypothermia case with an underlying diabetic ketoacidosis

Hypothermia can occur in patients with diabetic ketoacidosis (DKA), and these two conditions can exacerbate each other. Fatal hypothermia and DKA have overlapping features and findings such as Wischnewsky spots (WS), black esophagus, basal subnuclear vacuolization in the renal tubule, dehydration, and increased acetone levels. Therefore, it may be challenging to differentiate or clarify the context of these two conditions. Herein, we report a case of a 49-year-old man with type 1 diabetes who was found lying in his house in mid-winter. He experienced cardiopulmonary arrest 10 h after the initial discovery and died at the hospital. On autopsy, florid left cardiac blood was observed. Black discoloration of the distal part of the esophageal mucosa, widespread WS in the gastric mucosa, and black discoloration of the duodenal mucosa were observed. Histologically, neutrophil infiltration in the esophageal mucosa, neutrophil infiltration and bleeding in the gastric mucosa, basal subnuclear vacuolization and Armanni-Ebstein lesion in the renal tubule epithelium in the kidney, and hyalinization of the islets of Langerhans were observed in the pancreas. Blood acetone and β-hydroxybutyrate levels were 538 µg/mL and 8947 µmol/L, respectively. Glycated hemoglobin A1c and glucose levels were 16.2% and 883 mg/dL, respectively, while C-reactive protein level was 3.64 mg/dL. In conclusion, obnubilation due to DKA was assumed to be the underlying cause of hypothermia, and the combination of these two conditions led to the outcome of death. The concurrent presence of these conditions likely contributed to the conspicuous mucosal findings in the upper gastrointestinal tract.

Establishing vitreous glucose and beta-hydroxybutyrate thresholds to assist in the diagnosis of hypothermia

The post-mortem diagnosis of hypothermia is challenging to establish due to the lack of pathognomonic findings and the confounding problem that any comorbidity may account for death. A 4-year retrospective case-control study was performed to compare the vitreous glucose and beta-hydroxybutyrate (BHB) concentrations between hypothermia deaths and controls. Over the study period 34 cases of hypothermia and 39 controls were analyzed. Hypothermia deaths versus controls had higher mean vitreous glucose (2.93 mmol/L vs. 1.14 mmol/L; p < 0.0001), BHB (1.89 mmol/L vs. 1.35 mmol/L; p = 0.01), and combined glucose+BHB (4.83 mmol/L vs. 2.46 mmol/L; p < 0.0001). Receiver operating characteristic (ROC) curves showed that the best model for predicting hypothermia in all cases was a combined vitreous glucose+BHB threshold of 2.03 mmol/L (sensitivity 88.2 %; specificity 56.4 %). A sub-group analysis broken down by detectable levels of blood ethanol showed that cases of hypothermia with and without ethanol maintained higher median vitreous glucose relative to the controls (2.05 vs. 0.35 mmol/L and 2.70 vs. 0.65 mmol/L; p = 0.02), however median BHB was only significantly elevated when ethanol was absent (1.88 vs. 1.42 mmol/L; p < 0.0001). Subsequent ROC curve analysis demonstrated that a better model for predicting hypothermia was in cases when blood ethanol was absent. In those deaths vitreous BHB alone had the best area under the curve, with an optimum threshold of 1.83 mmol/L (sensitivity 83.3 %; specificity 96.3 %). This study shows that post-mortem vitreous glucose and BHB are useful ancillary studies to assist in the diagnosis of hypothermia. Ethanol however is a confounder and can alter the utility of vitreous BHB when diagnosing hypothermia in those who have consumed alcohol prior to death.

Wischnewski Spots in a Case of Hyperosmolar Hyperglycemic State

ABSTRACT

Wischnewski spots were first described as a common finding in gastric mucosa of decedents exposed to hypothermic environmental conditions. In recent literature, they were also reported in cases of diabetic ketoacidosis, pancreatitis, and fatal burns. Although Wischnewski spots are not specific to cases of hypothermia, we present a case that further supports this contention. We report a case of a middle-aged woman with type 2 diabetes who died of complications of hyperosmolar hyperglycemic state. Although there were no features of hypothermia, she presented with Wischnewski spots in the gastric mucosa. On histology, the gastric mucosa contained brown-black pigmentations with no neutrophilic infiltration. Biochemical analysis from vitreous humor and femoral blood showed marked elevation of glucose levels, low concentration of ketone bodies, pseudohyponatremia, and prerenal azotemia. The autopsy findings in this case discussion shed light to the possible genesis and pathophysiology of Wischnewski spots and highlight an additional differential diagnosis for these lesions.

Biological Mechanisms behind Wischnewsky Spots Finding on Gastric Mucosa: Autopsy Cases and Literature Review

Hypothermia is an emergency caused by the lowering of the central body temperature with a slowdown of basic vital functions. Reduced mobility, old age, psychiatric or metabolic disorders are relevant risk factors. Diagnosis of death from hypothermia is a challenge, as there are no pathognomonic signs, and supportive findings can be inconstant. Wischnewsky Spots (WS) are blackish lesions of gastric mucosa, typically associated with hypothermic death. The pathophysiology of these lesions is still uncertain. The aim of this paper is to investigate the pathological mechanisms determining the appearance of WS by analyzing the current scientific knowledge in this area. We performed a narrative review of the literature published in the last 20 years, comparing the results with three cases of hypothermia reported from our experience. The review proved that WS show a multifactorial etiology, i.e., not only body temperature decrease, but also various extrinsic and intrinsic factors, such as physical and psychological stress, agony, causa mortis and metabolic comorbidities. The review summarizes the current knowledge in the field of incidence, pathology and morphology of WS by proposing some scientific and technical points for clinical and forensic analysis of this phenomenon.

Renal Tubular Epithelial Subnuclear Vacuolization in Hypothermia and Diabetic Ketoacidosis-A Retrospective Autopsy Study

ABSTRACT

Subnuclear vacuolization of the renal tubular epithelium refers to discrete lipid vacuoles displacing the nuclei toward the lumen. This phenomenon has been associated with conditions sharing fatal ketoacidosis as a common denominator. This retrospective study aimed to investigate renal tubular epithelial subnuclear vacuolization and other postmortem examination findings in fatal hypothermia and diabetic ketoacidosis (DKA) cases.Fourteen cases with hypothermia and 19 cases with DKA were included. More cases with DKA had focal or diffuse subnuclear vacuolization compared with hypothermia cases (89% vs 43%; P = 0.007). In 6 cases with DKA, formalin pigment was detected within subnuclear vacuoles, whereas no case with hypothermia had formalin pigment deposition. Comparative analyses of hypothermia and DKA cases revealed further differences: Vitreous beta-hydroxybutyrate was higher in the DKA group compared with the hypothermia group (P = 0.044), whereas blood ethanol concentrations were higher in the latter (P = 0.008). Hypothermia cases were older compared with the DKA cases (P = 0.022).When all cases were included in the statistical analysis, cases with subnuclear vacuolization had higher vitreous beta-hydroxybutyrate and blood ethanol concentrations (P = 0.029 and 0.023, respectively). The findings corroborate the results of previous studies suggesting a link between subnuclear vacuolization and increased levels of ketoacidosis.

Clinicopathologic Appearance of Advanced Ketoacidosis With Basal Vacuolation in Renal Tubules

CONTEXT.—

Basal vacuolization (BV) in renal tubules is a histopathologic hallmark of advanced ketoacidosis that enables us to retrospectively diagnose these cases.

OBJECTIVE.—

To clarify the pathologic background and serologic findings of ketoacidosis with BV, and to reveal the pathologic findings by each pathologic background.

DESIGN.—

We examined 664 serial autopsy cases. A systemic histopathologic examination and measurement of serum β-hydroxybutyrate concentration were performed for the cases with BV. The extent of steatosis and fibrosis in the organs and the degree of coronary artery stenosis were semiquantitatively investigated. Immunohistochemistry for adipophilin was also performed to analyze its usefulness for the pathologic diagnosis.

RESULTS.—

Basal vacuolization was found in 16 cases, all of which showed a pathologic serum β-hydroxybutyrate concentration. The main background of ketoacidosis was considered as alcohol abuse in 6 cases, diabetes in 5, malnutrition in 3, and hypothermia and infection in 1 case each. Severe hepatic fibrosis was observed only in the alcohol-abuser group. Moreover, cardiac steatosis was more severe in patients with possible alcohol abuse than in those with other causes. Immunohistochemistry for adipophilin showed immunoreactivity consistent with BV in 13 of 16 cases. There was no correlation between β-hydroxybutyrate concentration and either the postmortem or storage interval.

CONCLUSIONS.—

Basal vacuolization may be a useful finding for detecting ketoacidosis cases in a postmortem investigation. Serum β-hydroxybutyrate was a stable and reliable compound for the definitive diagnosis of ketoacidosis in such cases. The present study showed that pathologic changes in some organs may vary by each pathologic background of ketoacidosis with BV.

The Vital Role of Thanatochemistry in the Postmortem Diagnostic of Diabetic Ketoacidosis-Case Report

Diabetic ketoacidosis (DKA) is a lethal acute hyperglycemic complication of diabetes mellitus (DM) and it represents the initial manifestation of DM in about 15-20% of cases in adults and about 30-40% of cases in children. Postmortem diagnosis of DKA can only be made by applying thanatochemistry. Biochemistry applied postmortem is viewed with skepticism by many practitioners in the forensic field, completely lacking in many forensic services around the world, and especially in the national ones. This article aims to underline the importance of the postmortem application of biochemistry by reviewing the case of a person in the third decade of life who died suddenly at home due to diabetic ketoacidosis (DKA), whose autopsy was performed at an early PMI of approximately 24 h. Routine postmortem examinations (macroscopic, anatomopathological, and toxicological) could not establish a clear cause of death. When attention was turned to biochemical determinations (i.e., determination of glycated hemoglobin, glucose and ketone bodies (acetone, beta-hydroxybutyrate) in the blood, vitreous humor, and cerebrospinal fluid), the identified values clarified the thanatogenic mechanisms by establishing the diagnosis of DKA.

Detection and Classification of Novel Renal Histologic Phenotypes Using Deep Neural Networks

With the advent and increased accessibility of deep neural networks (DNNs), complex properties of histologic images can be rigorously and reproducibly quantified. We used DNN-based transfer learning to analyze histologic images of periodic acid-Schiff-stained renal sections from a cohort of mice with different genotypes. We demonstrate that DNN-based machine learning has strong generalization performance on multiple histologic image processing tasks. The neural network extracted quantitative image features and used them as classifiers to look for differences between mice of different genotypes. Excellent performance was observed at segmenting glomeruli from non-glomerular structure and subsequently predicting the genotype of the animal on the basis of glomerular quantitative image features. The DNN-based genotype classifications highly correlate with mesangial matrix expansion scored by a pathologist (R.E.C.), which differed in these animals. In addition, by analyzing non-glomeruli images, the neural network identified novel histologic features that differed by genotype, including the presence of vacuoles, nuclear count, and proximal tubule brush border integrity, which was validated with immunohistologic staining. These features were not identified in systematic pathologic examination. Our study demonstrates the power of DNNs to extract biologically relevant phenotypes and serve as a platform for discovering novel phenotypes. These results highlight the synergistic possibilities for pathologists and DNNs to radically scale up our ability to generate novel mechanistic hypotheses in disease.

Biochemical Differences Between Vitreous Humor and Cerebral Spinal Fluid in a Death From Diabetic Ketoacidosis

Biochemical analysis of cerebrospinal fluid (CSF) and vitreous humor (VH) forms an important diagnostic ancillary test at autopsy. Cerebrospinal fluid can be sampled from the ventricular system (VA) and from lumbar puncture (LP), whereas VH can be sampled from the orbits. Biochemical electrolytes seem to vary between VH and CSF collected from different sites, but whether there is any difference in glucose and β-hydroxybutyrate is unclear. We present a case report of a 21-year-old man who died of diabetic ketoacidosis confirmed at autopsy. Ventricular system, LP, and VH were biochemically analyzed and showed that glucose was highest in VH (41 mmol/L) and was 6 and 8 mmol/L higher than CSF in the LP and VA, respectively. β-Hydroxybutyrate was also highest in VH (20 mmol/L) and was 5 and 6 mmol/L higher than LP and VA, respectively. Our findings suggest that postmortem CSF glucose and β-hydroxybutyrate may not truly reflect that of VH and vary between CSF sampling sites.