Histological examination in sudden unexpected death in infancy: evidence base for histological sampling

Identification of bacterial pathogens in sudden unexpected death in infancy and childhood using 16S rRNA gene sequencing

Background

Sudden unexpected death in infancy (SUDI) is the most common cause of post-neonatal death in the developed world. Following an extensive investigation, the cause of ~40% of deaths remains unknown. It is hypothesized that a proportion of deaths are due to an infection that remains undetected due to limitations in routine techniques. This study aimed to apply 16S rRNA gene sequencing to post-mortem (PM) tissues collected from cases of SUDI, as well as those from the childhood equivalent (collectively known as sudden unexpected death in infancy and childhood or SUDIC), to investigate whether this molecular approach could help identify potential infection-causing bacteria to enhance the diagnosis of infection.

Methods

In this study, 16S rRNA gene sequencing was applied to de-identified frozen post-mortem (PM) tissues from the diagnostic archive of Great Ormond Street Hospital. The cases were grouped depending on the cause of death: (i) explained non-infectious, (ii) infectious, and (iii) unknown.

Results and conclusions

In the cases of known bacterial infection, the likely causative pathogen was identified in 3/5 cases using bacterial culture at PM compared to 5/5 cases using 16S rRNA gene sequencing. Where a bacterial infection was identified at routine investigation, the same organism was identified by 16S rRNA gene sequencing. Using these findings, we defined criteria based on sequencing reads and alpha diversity to identify PM tissues with likely infection. Using these criteria, 4/20 (20%) cases of unexplained SUDIC were identified which may be due to bacterial infection that was previously undetected. This study demonstrates the potential feasibility and effectiveness of 16S rRNA gene sequencing in PM tissue investigation to improve the diagnosis of infection, potentially reducing the number of unexplained deaths and improving the understanding of the mechanisms involved.

Prominent Intrapulmonary Shunt Vessels and Altered Lung Development in Infants With Sudden Unexplained Infant Death

The purpose of this study was to evaluate intrapulmonary arteriovenous shunts in patients with and without sudden unexplained infant death. We identified open intrapulmonary bronchopulmonary anastomoses as potential pathways for right-to-left shunt in a subset of infants with sudden unexplained infant death.

A Comprehensive Review of Pathological Examination in Forensic Medicine: Past, Present, and Future

Pathological examination (PE) encompasses a gross or macroscopy and histopathological or microscopic examination. It is prudent in finding the cause of death (COD) in clinical and medicolegal autopsies. There are various auxiliary techniques in the form of clinical history, communication, specialized training, and protocols for consolidation of the PE results. After a thorough search of the literature in PubMed with relevant keywords along with further analysis of the results, it emerged that even with the modernization of forensic medicine, a PE is unbeatable in detecting the COD. It has various useful aspects, apart from regular finding the COD, such as in student teaching, epidemiology of disease, audit tool, and quality assurance. There are also limitations of PE, which should be dealt with great caution. Hence, limitations must be understood by a forensic expert as well as a pathologist. In this review, all factors that are related to PE in any manner are discussed in detail, and the scope for improving the quality of PE to be relevant in the present scenario is reviewed. It is a comprehensive reassessment of the literature review that also casts light on the future along with a critical analysis of the facts that deal with PE.

Stillbirth and intrauterine fetal death: role of routine histological organ sampling to determine cause of death

OBJECTIVES

Guidelines for the investigation of intrauterine death and sudden unexpected death in infancy (SUDI) recommend, based on expert opinion, autopsy procedures and tissue sampling strategies for histological analysis. Although stillbirth is much more common than SUDI, there have been no large-scale studies published which evaluate the usefulness of histological evaluation of specific organs in stillbirth for determining cause of death. Our aim was to evaluate the use of macroscopic and microscopic assessment of internal organs to determine cause of intrauterine death.

METHODS

As part of a larger study evaluating several aspects of autopsy findings in intrauterine death, a dedicated database was used to collate antenatal and postmortem examination details for cases of intrauterine death examined between 2005 and 2013 at two tertiary specialist centers in London, UK. Histological findings for all organs were examined in relation to the final cause of death, as determined by objective criteria.

RESULTS

Among 1064 intrauterine deaths, the majority (> 80%) of cases had internal organs that were normal on both macroscopic and microscopic examination. There was no case in which histological cardiac examination provided the cause of death when the macroscopic appearance of the heart was normal. Microscopic examination of lung tissue revealed 13 (1%) cases with histological abnormalities that provided the cause of death when the macroscopic appearance was normal, but there was only one (0.1%) case in which the diagnosis would not have been apparent on placental examination: a case of congenital cytomegalovirus infection. There was no case in which microscopic examination of macroscopically normal liver, kidneys, adrenals, spleen, thymus, intestines, pancreas, brain or thyroid provided the cause of death.

CONCLUSION

In this large series of autopsies in cases of intrauterine death, only around 1% of cases demonstrated histological abnormalities which provided the cause of death when the internal organs appeared normal macroscopically. There was no case in which routine histological examination of most tissues provided diagnostically useful information that was not apparent from other examinations, such as placental pathology. There is little benefit, purely in terms of determining cause of death, in obtaining tissue from most macroscopically normal organs for routine histological examination. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Paediatric and perinatal postmortem imaging: the need for a subspecialty approach

Paediatric postmortem imaging is distinct and different from adult postmortem imaging due to differences in disease aetiology, pathology and imaging approaches, which require a particular skill set to maximise its yield and clinical utility. Practitioners need to have expertise in several aspects of radiology, including both plain radiographs and cross-sectional imaging modalities, knowledge of specialist techniques, and familiarity with the unique range of pathologies in this patient population, including perinatal pathology. Here we outline the training requirements that should be considered to establish such a service.

Parental acceptance of minimally invasive fetal and neonatal autopsy compared with conventional autopsy

OBJECTIVE

To determine parental acceptance of minimally invasive autopsy (MIA) involving postmortem imaging and organ tissue sampling compared with conventional autopsy and to compare the acceptability of percutaneous versus laparoscopic-guided biopsy.

METHODS

Following termination of pregnancy parents were offered the option of traditional autopsy and subsequently interviewed about their acceptance of MIA. The McNemar test for paired samples was used to assess the difference in acceptance of MIA and conventional autopsy. The Wilcoxon signed-rank test for paired samples was used to compare the acceptance score for percutaneous versus laparoscopic-guided biopsy. Logistic regression was selected to study the association of parental acceptance of conventional autopsy and MIA with different variables.

RESULTS

Conventional autopsy was accepted by 42 (60.0%) of the 70 parents. Regression analysis showed that non-Muslim faith was the only factor significantly associated with acceptance of conventional autopsy (p = 0.030). Of 28 parents who initially refused conventional autopsy, 13(46.4%) subsequently accepted MIA, increasing acceptance to 78.6% (p < 0.001). Regression analysis showed that none of the factors significantly affected MIA acceptance. Parents expressed no preference between postmortem percutaneous versus laparoscopic-guided biopsy (p = 0.061).

CONCLUSION

Post-mortem imaging combined with systematic organ biopsies is highly acceptable among all parents independent of their religion and the method used for organ biopsy.

Comparison of conventional autopsy and magnetic resonance imaging in determining the cause of sudden death in the young

BACKGROUND

Sudden death in the young is a tragic complication of a number of medical diseases. There is limited data regarding the utility of post-mortem Magnetic Resonance (MR) imaging and Computer Tomography (CT) scanning in determining the cause of sudden death. This study sought to compare the accuracy of post-mortem cross-sectional imaging (MR and CT) with the conventional autopsy in determining the cause of sudden death in the young.

METHODS

Consecutive patients from 2010 to 2012 (aged 1-35 years) who had sudden death were included. Patients were scanned by CT and 1.5 T MR imaging prior to the conventional autopsy being performed. The primary outcome was diagnostic congruence between imaging and conventional autopsy.

RESULTS

In 17 patients studied, the mean age at death was 23 ± 11 years, with a male predominance (n = 12; 71%). The most common cause of death was a primary cardiac pathology (n = 8; 47%), including ARVC (24%) and ischemic heart disease (12%). Non-cardiac causes identified included pulmonary embolism (6%), and aortic dissection (6%). MR imaging correctly identified the diagnosis in 12 patients who subsequently had positive findings at conventional autopsy, while the diagnosis in the remaining 5 cases remained unexplained. MR imaging was found to be highly sensitive (100%) with a high negative (100%) and positive (80%) predictive value.

CONCLUSIONS

Dedicated post-mortem MR imaging of the heart and brain is a useful modality in determining the cause of sudden death in children and young adults, particularly in situations where a conventional autopsy cannot be performed for logistic, cultural or personal reasons.

Minimally invasive, imaging guided virtual autopsy compared to conventional autopsy in foetal, newborn and infant cases: study protocol for the paediatric virtual autopsy trial

Background

In light of declining autopsy rates around the world, post-mortem MR imaging is a promising alternative to conventional autopsy in the investigation of infant death. A major drawback of this non-invasive autopsy approach is the fact that histopathological and microbiological examination of the tissue is not possible. The objective of this prospective study is to compare the performance of minimally invasive, virtual autopsy, including CT-guided biopsy, with conventional autopsy procedures in a paediatric population.

Methods/Design

Foetuses, newborns and infants that are referred for autopsy at three different institutions associated with the University of Zurich will be eligible for recruitment. All bodies will be examined with a commercial CT and a 3 Tesla MRI scanner, masked to the results of conventional autopsy. After cross-sectional imaging, CT-guided tissue sampling will be performed by a multifunctional robotic system (Virtobot) allowing for automated post-mortem biopsies. Virtual autopsy results will be classified with regards to the likely final diagnosis and major pathological findings and compared to the results of conventional autopsy, which remains the diagnostic gold standard.

Discussion

There is an urgent need for the development of alternative post-mortem examination methods, not only as a counselling tool for families and as a quality control measure for clinical diagnosis and treatment but also as an instrument to advance medical knowledge and clinical practice. This interdisciplinary study will determine whether virtual autopsy will narrow the gap in information between non-invasive and traditional autopsy procedures.

Trial Registration

ClinicalTrials.gov: NCT01888380

Post-mortem MRI versus conventional autopsy in fetuses and children: a prospective validation study

BACKGROUND

Post-mortem MRI is a potential diagnostic alternative to conventional autopsy, but few large prospective studies have compared its accuracy with that of conventional autopsy. We assessed the accuracy of whole-body, post-mortem MRI for detection of major pathological lesions associated with death in a prospective cohort of fetuses and children.

METHODS

In this prospective validation study, we did pre-autopsy, post-mortem, whole-body MRI at 1·5 T in an unselected population of fetuses (≤24 weeks' or >24 weeks' gestation) and children (aged <16 years) at two UK centres in London between March 1, 2007 and Sept 30, 2011. With conventional autopsy as the diagnostic gold standard, we assessed MRI findings alone, or in conjunction with other minimally invasive post-mortem investigations (minimally invasive autopsy), for accuracy in detection of cause of death or major pathological abnormalities. A radiologist and pathologist who were masked to the autopsy findings indicated whether the minimally invasive autopsy would have been adequate. The primary outcome was concordance rate between minimally invasive and conventional autopsy.

FINDINGS

We analysed 400 cases, of which 277 (69%) were fetuses and 123 (31%) were children. Cause of death or major pathological lesion detected by minimally invasive autopsy was concordant with conventional autopsy in 357 (89·3%, 95% CI 85·8-91·9) cases: 175 (94·6%, 90·3-97·0) of 185 fetuses at 24 weeks' gestation or less, 88 (95·7%, 89·3-98·3) of 92 fetuses at more than 24 weeks' gestation, 34 (81·0%, 66·7-90·0) [corrected] of 42 newborns aged 1 month or younger, 45 (84·9%, 72·9-92·1) of 53 infants aged older than 1 month to 1 year or younger, and 15 (53·6%, 35·8-70·5) of 28 children aged older than 1 year to 16 years or younger. The dedicated radiologist or pathologist review of the minimally invasive autopsy showed that in 165 (41%) cases a full autopsy might not have been needed; in these cases, concordance between autopsy and minimally invasive autopsy was 99·4% (96·6-99·9).

INTERPRETATION

Minimally invasive autopsy has accuracy similar to that of conventional autopsy for detection of cause of death or major pathological abnormality after death in fetuses, newborns, and infants, but was less accurate in older children. If undertaken jointly by pathologists and radiologists, minimally invasive autopsy could be an acceptable alternative to conventional autopsy in selected cases.

FUNDING

Policy research Programme, Department of Health, UK.

Relationship of red splenic arteriolar hyaline with rapid death: a clinicopathological study of 82 autopsy cases

Background

Little is known about the relationship between splenic arteriolar hyaline and cause of death. The purpose of this retrospective study was to evaluate the clinicopathological significance of splenic arteriolar hyaline in autopsy cases and estimate the applicability of hyaline for diagnosing the cause and rapidity of death.

Methods

Archival data and histological slides from 82 cases were reviewed retrospectively. One section of each spleen was evaluated microscopically. The tinctorial pattern of splenic arteriolar hyaline was examined with Heidenhain’s Azan trichrome stain, and the relationships between this pattern and age, cause of death, and rapidity of death were investigated.

Results

Fifty-four cases demonstrated hyaline change, with 3 different tinctorial patterns: red, blue, and a combination of red and blue. The 3 patterns coexisted in various proportions in each tissue section. Frequency of the blue pattern increased with age (P < 0.01) and was unrelated to cause of death. By contrast, the red pattern was unrelated to age and appeared with different frequency according to cause of death. The red pattern appeared with significantly higher frequency in the circulatory disease group and the drowning and asphyxia group (both P < 0.01). Moreover, the presence of the red pattern had high specificity for the detection of rapidly fatal cases. The combination of the 2 colors was excluded from clinicopathological analyses due to its admixed nature.

Conclusions

Estimation of splenic arteriolar hyaline with Heidenhain’s Azan trichrome stain is useful for assessment of the cause and rapidity of death.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1132441651796836

Whole-body post-mortem computed tomography compared with autopsy in the investigation of unexpected death in infants and children

OBJECTIVES

To investigate the contribution of whole-body post-mortem computed tomography (PMCT) in sudden unexpected death in infants and children.

METHODS

Forty-seven cases of sudden unexpected death in children investigated with radiographic skeletal survey, whole-body PMCT and autopsy were enrolled. For imaging interpretation, non-specific post-mortem modifications and abnormal findings related to the presumed cause of death were considered separately. All findings were correlated with autopsy findings.

RESULTS

There were 31 boys and 16 girls. Of these, 44 children (93.6 %) were younger than 2 years. The cause of death was found at autopsy in 18 cases (38.3 %), with 4 confirmed as child abuse, 12 as infectious diseases, 1 as metabolic disease and 1 as bowel volvulus. PMCT results were in accordance with autopsy in all but three of these 18 cases. Death remains unexplained in 29 cases (61.7 %) and was correlated with no abnormal findings on PMCT in 27 cases. Major discrepancies between PMCT and autopsy findings concerned pulmonary analysis.

CONCLUSIONS

Whole-body PMCT may detect relevant findings that can help to explain sudden unexpected death and is essential for detecting non-accidental injuries. We found broad concordance between autopsy and PMCT, except in a few cases of pneumonia. It is a non-invasive technique acceptable to relatives.

KEY POINTS

• Whole-body post-mortem computed tomography (PMCT) is an effective non-invasive method. • Whole-body PMCT is essential for detecting child abuse in unexpected death. • There is concordance on cause of death between PMCT and autopsy. • Whole-body PMCT could improve autopsy through dissection and sampling guidance. • PMCT shows findings that may be relevant when parents reject autopsy.

Sudden infant death in an 8-month-old baby with dengue virus infection: searching for virus in postmortem tissues by immunohistochemistry and Western blotting

Sudden infant death due to dengue virus infection is very rare. An 8-month-old male infant was found unresponsive during a nap in his nursery school. We emphasize the usefulness of dengue viral antigens as a postmortem diagnostic technique to demonstrate the presence of virus in human tissue specimens by immunohistochemistry and Western blotting.