The effects of drying the rinsed dissected heart on postmortem heart weight.

Blood and blood clots should be removed from the heart chambers before being weighed. The actual method in removing blood and blood clots may vary and can include manual removal with subsequent rinsing the heart in water. It is unclear whether drying the rinsed heart affects the heart weight. The objective of this article was to investigate the effects drying the rinsed dissected heart (residual rinsing water) on postmortem heart weight. The prospective study compared 44 dissected heart weights after being rinsed and after being pat dried. An average 18-20 g of residual rinsing water (4% of heart weight) was present in the dissected heart. The amount of residual rinsing water correlates positively with heart weight. The effects of drying the rinsed dissected heart were considered clinically insignificant. Although being clinically insignificant, this study highlights the lack of standardized approach in weighing the heart and the potential implications in interpreting heart weights.

Heart Weight Is an Independent Factor Associated With, But Is a Poor Predictor for, Sudden Cardiac Death.

ABSTRACT: An enlarged heart can cause electrical instability and impaired contractility, leading to fatal arrhythmia and acute heart failure, and is associated with sudden cardiac death. However, there is limited postmortem evidence on whether heart weight is an independent factor associated with sudden cardiac death. This 18-month retrospective study examined 108 adult heart weights in which all the hearts were weighed after dissection, blood and blood clots removed, rinsed in water, and pat dried. The multivariate logistic regression analysis showed heart weight was an independent factor associated with sudden cardiac death. However, after normalization, the heart weight was a poor predictor of sudden cardiac death with an area under the curve less than 0.7 in the plotted receiver operating characteristic curve.

A 5-Year Retrospective Study on Infant Homicide Presenting as Cot Death: Are We Missing Infant Homicides?

ABSTRACT: Being found dead in cot or bed is the most common presentation encountered with infant deaths. These deaths are often associated with unsafe sleep environment. The postmortem examination in such cases is often negative, and along with family objections, cultural, and other factors, may lead to a coroner considering not authorizing a postmortem examination. However, not identifying a homicide is a potential risk if a postmortem examination is not performed. This 5-year retrospective study investigated the proportion of infant homicide death initially presenting as cot death. Of a total of 103 cases of infants initially presenting as being found dead in cot or bed, 3 (approximately 3%) were classified as homicides after postmortem examination. During the study period, a total of 9 infant homicides were reported, translating to 33% (3 of 9) of infant homicides presented as cot deaths. Postmortem radiology was a valuable adjunct, but was unable to recognize 2 of the homicide cases with traumatic head injuries (with subdural hemorrhage and brain injury only). We strongly advocate that all infant deaths presenting as cot death require a full postmortem examination.

Terminal Ileum Perforation: A Rare Complication of Verocytotoxigenic Escherichia coli Infection in an Adult With Prader-Willi Syndrome.

ABSTRACT: Intestinal perforation is an uncommon complication and presentation of verocytotoxigenic Escherichia coli (VTEC) infection in individuals with Prader-Willi syndrome (PWS). The common site of perforation from VTEC infection is in the colon (and almost exclusively in the pediatric population), whereas PWS is in the stomach. Terminal ileum perforation is uncommon and is not reported in either these 2 conditions. We report a death from terminal ileum perforations in an adult who had PWS and was infected with VTEC. Potential reasons why the perforation occurred at this rare location, rather than in other more common location, in an adult are discussed.

Classifying Microscopic Acute and Old Myocardial Infarction Using Convolutional Neural Networks.

ABSTRACT: Convolutional neural network (CNN) has advanced in recent years and translated from research into medical practice, most notably in clinical radiology and histopathology. Research on CNNs in forensic/postmortem pathology is almost exclusive to postmortem computed tomography despite the wealth of research into CNNs in surgical/anatomical histopathology. This study was carried out to investigate whether CNNs are able to identify and age myocardial infarction (a common example of forensic/postmortem histopathology) from histology slides. As a proof of concept, this study compared 4 CNNs commonly used in surgical/anatomical histopathology to identify normal myocardium from myocardial infarction. A total of 150 images of the myocardium (50 images each for normal myocardium, acute myocardial infarction, and old myocardial infarction) were used to train and test each CNN. One of the CNNs used (InceptionResNet v2) was able to show a greater than 95% accuracy in classifying normal myocardium from acute and old myocardial infarction. The result of this study is promising and demonstrates that CNN technology has potential applications as a screening and computer-assisted diagnostics tool in forensic/postmortem histopathology.

Levels of haemolysis have no effect on femoral vein post-mortem tryptase levels.

Haemolysis is reported to be an artefact that may alter post-mortem tryptase levels. However, previous studies did not sample peripheral blood using newly standardised methods. Recent studies have shown that some previously recognised peri- and post-mortem confounders can be muted by careful sample collection with first clamping and then sampling the femoral vein. This prospective study investigated the relationship between the degree of haemolysis of the blood samples and femoral vein post-mortem tryptase levels when sampled using this recommended method. Seventy consecutive post-mortem tryptase levels in non-anaphylactic deaths were compared to the degree of haemolysis of these samples, and results showed no significant correlation between them. The mean post-mortem tryptase level was 9.5 µg/L. This study demonstrated that the effects of haemolysis on femoral vein post-mortem tryptase was negligible when the blood was sampled using the recommended sampling method. Future studies on post-mortem tryptase as well as other typically used blood markers in forensics are recommended to adopt this method of blood sampling in routine practice.

Hemorrhagic Pseudocyst: A Rare Cerebral Mass Lesion Causing Death. A Case Report and Brief Review of Literature.

ABSTRACT: Mass lesions in the brain encompass a wide range neoplastic and nonneoplastic entities. These can present as a diagnostic pitfall, with nonspecific, overlapping symptoms and similar appearances on radiology. They may cause death through varied mechanisms, either specific to the underlying pathophysiology or due to the space-occupying effect of the lesion. We report a case of fatal hemorrhagic cerebral pseudocyst, a rare mass lesion, associated with a cerebral varix, causing death in a morbidly obese individual. To the best of our knowledge, there is no previous documentation in the postmortem literature of this entity as a cause of death. This case aims to document this rare entity in the differential diagnosis of a tumor-like lesion in the brain, highlight the clinical difficulty in its assessment, and demonstrate an uncommon mechanism of death, of a mass lesion acting as a focus causing seizures, with resulting hypoxia due to effects of morbid obesity and heart failure.

Differences Between Central and Peripheral Postmortem Tryptase Levels.

ABSTRACT: Postmortem tryptase is a commonly used biochemical test to aid in the diagnosis of fatal anaphylaxis, which is currently recommended to be sampled from peripheral (femoral) veins because of a research showing comparatively elevated levels from central blood sources. Previous studies have used nonstandardized or nondocumented sampling methods; however, more recent research demonstrates that tryptase levels may vary depending on the sampling method. This study used the recommended sampling method of aspirating the femoral vein after clamping and compared in a pairwise comparison with aspiration of central venous and arterial blood sources (inferior vena cava and aorta) in 2 groups of 25 nonanaphylactic deaths. We found no statistically significant differences in postmortem tryptase between central and femoral vein blood; however, sporadic outliers in central blood (particularly aortic blood reaching levels above documented cutoffs for fatal anaphylaxis) were observed. Our findings provide evidence for the existing recommendations that femoral vein blood remains the preferred sample for postmortem tryptase over central blood.

Identifying gross post-mortem organ images using a pre-trained convolutional neural network.

Identifying organs/tissue and pathology on radiological and microscopic images can be performed using convolutional neural networks (CNN). However, there are scant studies on applying CNN to post-mortem gross images of visceral organs. This proof-of-concept study used 537 gross post-mortem images of dissected brain, heart, lung, liver, spleen, and kidney, which were randomly divided into a training and teaching datasets for the pre-trained CNN Xception. The CNN was trained using the training dataset and subsequently tested on the testing dataset. The overall accuracies were >95% percent for both training and testing datasets and have an F1 score of >0.95 for all dissected organs. This study showed that small datasets of post-mortem images can be classified with a very high accuracy using a pre-trained CNN. This novel area has the potential for future application in data mining, education and teaching, case review, research, quality assurance, auditing purposes, and identifying pathology.

Identifying Fatal Head Injuries on Postmortem Computed Tomography Using Convolutional Neural Network/Deep Learning: A Feasibility Study.

Postmortem computed tomography (PMCT) is a relatively recent advancement in forensic pathology practice that has been increasingly used as an ancillary investigation and screening tool. One area of clinical CT imaging that has garnered a lot of research interest recently is the area of "artificial intelligence" (AI), such as in screening and computer-assisted diagnostics. This feasibility study investigated the application of convolutional neural network, a form of deep learning AI, to PMCT head imaging in differentiating fatal head injury from controls. PMCT images of a transverse section of the head at the level of the frontal sinus from 25 cases of fatal head injury were combined with 25 nonhead-injury controls and divided into training and testing datasets. A convolutional neural network was constructed using Keras and was trained against the training data before being assessed against the testing dataset. The results of this study demonstrated an accuracy of between 70% and 92.5%, with difficulties in recognizing subarachnoid hemorrhage and in distinguishing congested vessels and prominent falx from head injury. These results are promising for potential applications as a screening tool or in computer-assisted diagnostics in the future.

Combining Postmortem Cerebrospinal Fluid Biochemistry With Lung-to-Body Ratio to Aid the Diagnosis of Salt Water Drowning.

Diagnosing drowning as a cause of death can pose many challenges for the forensic pathologist and a number of ancillary tests have been proposed to assist in the diagnosis, whether the body was in salt water or fresh water. Although elevated vitreous humor sodium and chloride is a reliable marker, its limitation to prolonged immersion has resulted in the recent investigation of cerebrospinal fluid (CSF) sodium and chloride as alternative matrix in cases of longer or unknown immersion times. This study investigated postmortem CSF from lumbar puncture (CSF_L_Na_Cl) and ventricular aspiration (CSF_Vent_Na_Cl), as well as lung/body (LB) ratio in the diagnosis of salt water drowning and performed comparison and combination testing of methods to improve diagnostic accuracy of the drowning diagnosis. This study found that CSF_L_Na_Cl was the most accurate method (89%) in the given cohort, but that CSF_Vent_Na_Cl and LB combined was the second most accurate method (83%), exceeding CSF_Vent_Na_Cl (77%) and LB (81%) used alone. These findings are useful for stratifying and prioritizing postmortem samples in the investigation of salt water drowning and also have significance for future studies using this methodology to combine and compare the accuracy of different investigations.

Significant Differences in PostMortem Heart Weight Before and After Dissection Using the Short-Axis Dissecting Method.

Correctly assessing heart weight can be critical at postmortem examination. The current international guidelines advocate using the short-axis method in dissecting the heart and the heart weighed when the blood is emptied. However, it did not specify at what point the heart should be weighed or how the blood should be emptied. This study compared heart weights at three different time points during the heart examination (immediately after dissecting out of the pericardial sac with blood still in chambers, blood washed/removed from heart chambers without the heart opened, and the heart completely opened, blood emptied, and pad dried). This was to illustrate the variation in measurement and potential errors when the heart is weighed at different time of dissection. The results show that there were statistical and clinical significant differences between the heart weights at each weighing points. We recommend the heart to be completely dissected with any blood and residual washing/rinsing water emptied before being weighed. Although performed in this study, the effect of pad drying the heart on heart weight was not explored and was a limitation in this study.

Ruptured Esophageal Varices From Metastatic Tumor in the Liver: A Case Report and Brief Review of Literature.

Ruptured esophageal varices can present as sudden death from gastrointestinal hemorrhage. The most common underlying pathology causing esophageal varices is cirrhosis leading to portal hypertension. However, not all esophageal varices arise from portal hypertension, and not all portal hypertensions are caused by cirrhosis. We present a rare case of ruptured esophageal varices casing death in an individual with metastatic tumor (high-grade) neuroendocrine tumor in the liver causing portal hypertension. This is, to the best of our knowledge, the first case report in the literature reporting a neuroendocrine tumor causing esophageal varices. This case report aims to document this rather rare entity, highlight another mechanism on how metastatic disease can result in sudden death, and give a brief review of literature on metastatic tumor in the liver causing esophageal varices.

Postmortem Tryptase Level in 120 Consecutive Nonanaphylactic Deaths: Establishing a Reference Range as <23 µg/L.

Postmortem tryptase is a useful biochemical test to aid the diagnosis of anaphylaxis. Multiple perimortem and postmortem factors have been documented to cause an elevation in postmortem tryptase level. One factor that was recently recognized to have an impact on postmortem tryptase level is correct sampling technique. A recent study recommended aspirating blood samples from a clamped femoral/external iliac vein to be used for reliable postmortem tryptase analysis. This study sampled 120 consecutive nonanaphylactic deaths in which all the peripheral bloods were sampled as recommended. Postmortem interval, resuscitation, different nonanaphylactic causes of death, sex, and age did not show any statistical significant relation to postmortem tryptase level in Student t test, Pearson correlation, and univariate and multivariate analyses. The mean (SD) postmortem tryptase level was 8.4 (5.2) µg/L (minimum, 1.0 µg/L; maximum, 36.1 µg/L; median, 7.3 µg/L). Using nonparametric methods, the postmortem tryptase reference range in nonanaphylactic death was established as <23 µg/L (97.5th percentile).

Elevation of Postmortem Cerebrospinal Fluid Sodium and Chloride Levels Is a Potential Adjunct Test in the Diagnosis of Salt Water Drowning.

Postmortem vitreous humor biochemistry is a useful test in the diagnosis of salt water drowning (SWD). A significant limitation of vitreous humor is the potential effect of prolonged immersion. A recent animal study and case report suggested that cerebrospinal fluid biochemistry may be an alternative to vitreous because it is more resistant to the effects of immersion, given its protected anatomical location. This study compared postmortem cerebrospinal fluid sodium and chloride (PMCSC) levels collected via ventricular aspiration (PMCSC_V) and via lumbar puncture (PMCSC_L) in 13 SWD and 31 nonimmersion deaths. It showed a significant elevation in PMCSC levels in SWD deaths for both PMCSC_V and PMCSC_L (P < 0.05). The areas under the curve on the receiver operating characteristic curves for PMCSC_V and PMCSC_L were 0.73 and 0.83, respectively. The optimal cutoff for PMCSC_V was 216 mmol/L (sensitivity, 0.60; specificity, 0.72; likelihood ratio, 1.80; positive predictive value, 0.45) and for PMCSC_L was 241 mmol/L (sensitivity, 0.78; specificity, 0.73; likelihood ratio, 2.89; positive predictive value, 0.46). This study supports PMCSC levels as another biochemical test that can potentially aid in the diagnosis of SWD, particularly in cases where vitreous humor samples are unavailable or uninterpretable.