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.

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.

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.

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.

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.

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.

The Potential Diagnostic Accuracy of Autopsy Lung Weights, Lung-Heart Ratio, and Lung-Body Ratio in Drowning Deaths.

Lung weights are often increased in drowning deaths as well as in other types of deaths. Lung weights may also vary with age, sex, and body weight. A variety of methods have been proposed to utilize lung weight data to assist with the diagnosis of drowning. The present study compared lung weight, lung-heart ratio (LH), and lung-body ratio (LB) between 50 consecutive drowning and 50 nonimmersion deaths in order to assess the accuracy in diagnosing drowning. Analysis revealed both LH and LB to be statistically higher in drowning deaths (P < 0.05), with LB being the most robust measurement. However, the overall diagnostic accuracies of lung weight, LH, and LB were poor to fair, and should therefore be used only in conjunction with the other diagnostic criteria.

Higher Heart Weight in New Zealand Maori and Pacific Islanders.

Heart weight is dependent on sex, age, height, and weight. Although previous autopsy studies showed no differences in heart weight between different ethnic groups, none have examined the New Zealand population of Maori and Pacific Islanders (Polynesians). The presented study compared heart weights between 101 European and 85 Polynesian suicide hanging deaths from New Zealand. Univariate linear regression coefficients for age, male sex, height, body weight, body mass index, and Polynesian ethnicity were positive and significant (P < 0.05). Apart from body mass index, subsequent multivariate analysis showed that all regression coefficients remained positive and significant (P < 0.05). Polynesian ethnicity seemed to be an independent predictor for increased heart weight in the study population. Apart from possible genetic factors, the higher heart weight in Polynesians may have other underlying reasons. Caution is required when interpreting heart weight in cases of sudden natural deaths, especially in this population.

Combining Postmortem Vitreous Sodium and Chloride and Lung-Body Ratio in Aiding the Diagnosing Saltwater Drowning.

Diagnosing death due to drowning can be difficult, and several postmortem findings have been postulated to aid the diagnosis. Increased lung weights are often seen in drowning deaths. Lung-body (LB) ratio was described to be the best anatomical lung measurement in diagnosing drowning. Postmortem vitreous humor sodium and chloride (PMVSC) was reported to be a useful biochemical test in diagnosing saltwater drowning when the immersion time is less than 1 hour (SWD1). The presented study compared the diagnostic accuracies between LB ratio, PMVSC, and their combination in diagnosing SWD1 in 20 SWD1 and 50 nonimmersion deaths. Classification tree models were used for analysis and revealed that combination of PMVSC and LB ratio was most accurate in diagnosing SWD1 (misclassification rate, 4%), followed by PMVSC (misclassification rate, 10%) and LB ratio (misclassification rate, 24%). A quantifiable diagnostic improvement was established when both LB ratio and PMVSC were used. After adjusting for interlaboratory variations, the developed tree models can be a reliable way in aiding the diagnosis of SWD1.

Elevated Postmortem Vitreous Sodium and Chloride Level in a Salt Water Drowning Death During Self-Contained Underwater Breathing Apparatus Diving With Diving Mask in Place: Case Report.

Elevation of postmortem vitreous sodium and chloride (PMVSC) levels in salt water drowning (SWD) is hypothesized to result from electrolyte changes in blood from salt water inhalation/ingestion during drowning. After approximately 1 hour after death, electrolytes may diffuse into the vitreous humor via the eye coverings. This hypothesis was based on a study where bovine eyeballs were immersed in salt water. There is no human study that could confirm that SWD would result in an initial elevation of PMVSC with no effects from immersion. We present an SWD during self-contained underwater breathing apparatus diving in which the face mask remained in its correct position while the deceased was underwater. The face mask would have prevented the orbits from being in direct contact with salt water and therefore stopped any effects of immersion on PMVSC. The PMVSC was 294 mmol/L, above control levels, and the reported cut-off of 259 mmol/L for a diagnosis SWD. The elevated PMVSC would unlikely be owing to immersion but SWD. This case report supports the observation that during SWD PMVSC would initially increase from salt water inhalation and ingestion and not from immersion.

Differences in Sampling Site on Postmortem Cerebrospinal Fluid Biochemistry: A Preliminary Study.

Cerebrospinal fluid (CSF) is often analyzed at postmortem. The presented preliminary study compared postmortem CSF samples for biochemical analysis from the subarachnoid space around the spinal cord and ventricular space of the brain. This study compared 15 paired CSF samples in which the CSF from the subarachnoid space via lumbar puncture had higher sodium and chloride levels and lower magnesium and potassium levels than CSF from the ventricles. The differences correlated significantly with the deceased's age and had a similar trend with postmortem interval. This study suggests that CSF from different collection sites has different electrolyte concentrations, which are age and possibly postmortem interval dependent. When collecting CSF, the pathologist should document the collection site, age, and postmortem interval, and the mixing of CSF samples from different sites should be avoided. Further studies are warranted to clarify other possible reasons to explain the observed differences.

Evaluation of autopsy and police reports in the investigation of sudden unexplained death in the young.

To evaluate police and autopsy reports in sudden unexplained deaths in 0-40 year olds. A structured, blind review of police and autopsy reports send to a cardiac genetic service from before (February 2006-December 2007) and after (January-December 2009) new best practice guidelines were introduced in Australia and New Zealand was performed. The reviews focused on reporting on: (1) presentation and clinical history, (2) cardiac autopsy, (3) histological tests and toxicology, and (4) detailed examination of coronary arteries. 110 reports were evaluated against the guidelines. 100 % reported location, 95 % activity at time of death, and 84 % some clinical history. Less than 25 % reported on family history, presence/absence of illicit drugs or alcohol, recorded a possible arrhythmic trigger, or history of fits/faints or collapses. Over 95 % listed heart weight, valvular examinations, pulmonary and some myocardial histology. Less than 50 % commented on septal, LV (left ventricle) and RV (right ventricle) wall thickness. Less than 50 % mentioned site of histology samples, or gave specific description of LV or RV histology or conduction system. Toxicology was not mentioned in a third. Histology of coronary arteries was described in only 18 %. Post guidelines reporting increased in some areas, e.g. in 1-40 year olds: antecedent symptoms (22-61 %), number and location of histology samples (0-47 %), and histology of coronary arteries (6-50 %). Most police and autopsy reports fall short of best practice guidelines. They have improved somewhat after the new guidelines were introduced, but need to be more consistent and particularly need to include significant negative findings.

Mortality after discharge from hospital following an episode of diabetic ketoacidosis.

AIMS: The rate of inpatient mortality associated with diabetic ketoacidosis (DKA) has steadily decreased in recent decades. However, there remains a significantly increased outpatient death rate following an episode of survived DKA. We undertook this study to investigate the observed increase in mortality following an episode of DKA. METHODS: We completed a retrospective cohort study to investigate rates and causes of death in people admitted to our hospital with DKA between 2013 and 2018. DKA was confirmed by pre-defined biochemical parameters and cause of death data was extracted from multiple sources. Follow-up was for two years after discharge for all participants with one-year mortality being the main time point for analysis. RESULTS: We identified 818 admissions to hospital with DKA, affecting 284 people. Twenty people died as inpatients and a further 40 people died during the two-year follow-up. Of these 60 participants, cause of death was able to be determined for 41 (68%), with most deaths occurring due to infection or macrovascular disease. Risk factors for death within a year of hospital discharge included older age, vascular complications of diabetes, intellectual impairment and residential care living. Those who survived an episode of DKA had a one-year age-corrected mortality rate 13 times higher than the general population. This was more marked in the younger cohort with those aged 15-39 years being 49 times more likely to die in the year after surviving a DKA admission compared to their general population counterparts. CONCLUSION: An episode of diabetic ketoacidosis is associated with a significant outpatient mortality risk with most deaths due to infectious or macrovascular causes. This study should prompt investigation of predictive scoring tools to identify those at increased mortality risk after DKA and encourage the development of targeted interventions to reduce mortality.

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.

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.

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.

An outbreak of deaths associated with AMB-FUBINACA in Auckland NZ.

BACKGROUND: AMB-FUBINACA is a synthetic cannabinoid that has been associated with periodic outbreaks of acute poisonings, but few fatalities. In late May, June and July 2017 Auckland, New Zealand, experienced an outbreak of deaths associated with AMB-FUBINACA that continued at a rate of about 2-3 per month through February 2019. The aim of this study was to define the demographic, circumstantial, pathological and toxicological characteristics of this outbreak. METHODS: All records of the Northern Forensic Pathology Service, Auckland Hospital, were reviewed in which the word "AMB-FUBINACA" was referenced, including initial police reports, autopsy reports and toxicology reports. Recorded data included age, sex, race/ethnicity, times and locations, cause of death, autopsy and toxicology findings, and a brief summary of the circumstances of death. Descriptive statistics were performed using IBM® SPSS® Statistics Version 24 and Microsoft® Excel® Version 14.7.2. FINDINGS: Sixty-four cases were identified. One sudden infant death and five cases where cause of death was due to trauma were excluded. Of the remaining 58 cases, 88% were male. Mean age was 42 years. In 95% of the deaths, AMB-FUBINACA alone or in combination with alcohol or another drug was listed as the primary or contributory cause of death. In 41 cases postmortem blood concentrations of AMB-FUBINACA acid were available, ranging from <45 ng/mL to >1000 ng/mL, mean 229 ng/mL, median 140 ng/mL. Comorbidities identified included mixed intoxications (29%), heart disease (47%) and obesity (16%). A mental health diagnosis was reported in 50%, and 40% were on antipsychotic medications. INTERPRETATION: This study presents characteristics, comorbidities and toxicological findings in a unique outbreak of deaths associated with the synthetic cannabinoid AMB-FUBINACA in Auckland, NZ. FUNDING: All work was funded as part of the usual employment of the authors in their respective institutions. No special funding sources are reported.