A practical classification schema incorporating consideration of possible asphyxia in cases of sudden unexpected infant death

The National Association of Medical Examiners Position Paper on the Investigation and Certification of Pediatric Deaths From Environmental Neglect

ABSTRACT

Pediatric deaths that occur because of environmental neglect often involve 4 common scenarios: (1) hyperthermia due to environmental exposure, (2) ingestion of an accessible drug or poison, (3) unwitnessed/unsupervised drownings, and (4) unsafe sleep practices. Given the same fact pattern, the manner of death will vary from accident to homicide to undetermined based on local custom and/or the certifier's training and experience. Medical examiner/coroner death certifications are administrative public health determinations made for vital statistical purposes. Because the manner of death is an opinion, it is understandable that manner determinations may vary among practitioners. No prosecutor, judge, or jury is bound by the opinions expressed on the death certificate. This position paper does not dictate how these deaths should be certified. Rather, it describes the challenges of the investigations and manner determinations in these deaths. It provides specific criteria that may improve consistency of certification. Because pediatric deaths often are of public interest, this paper provides the medical examiner/coroner with a professional overview of such manner determination issues to assist various stakeholders in understanding these challenges and variations.

Assessing Neglect in Pediatric Environmental Deaths: A Survey of Manner of Death Determinations

ABSTRACT

There are 4 common types of environmental pediatric deaths that may involve various degrees of neglect: hyperthermia, ingestion, drownings, and unsafe infant sleep practices. Because the circumstances surrounding each are disparate, there is no set of standards by which these factors may be weighed and interpreted. Given the same facts, the manner of death certification may differ depending upon training/experience and/or local practice.To assess certification variations, 147 board-certified forensic pathologists were surveyed for the choice of manner in scenarios with different degrees of negligence intent. In addition to evaluating certification consistency, the survey examined whether certain factors affected the choice. The results demonstrated strong consistency in certain scenarios and widely disparate certifications in others.Medical examiner/coroner certifications are administrative decisions for vital statistical purposes. The manner of death reflects an evidence-based conclusion, but because it is ultimately an opinion, determinations may vary. Based on the survey, some certification criteria were identified (ie, intent, child age, and knowingly placing a child in an environment with a reasonable risk of harm). Using these criteria may improve consistency, but it is unreasonable to expect 100% concordance. Understanding the certificate's role helps to place the manner in the proper legal and public health contexts.

A systematic review of the burden and risk factors of sudden infant death syndrome (SIDS) in Africa

Background

While sudden infant death syndrome (SIDS) has long been recognized as a leading preventable cause of infant mortality in high-income countries, little is known about the burden of SIDS in Africa. To address this knowledge gap, we conducted the first systematic review of SIDS-related publications in Africa. Our objective was to assess the prevalence of SIDS and its risk factors in Africa.

Methods

We systematically searched PubMed, Embase, Web of Science, Cochrane, and Google Scholar to identify studies published until December 26, 2020. Review authors screened titles and abstracts, and selected articles independently for full-text review. Risk of bias was assessed using the Newcastle Ottawa Scale (NOS) or a modification. Data on the proportion of infants who died of SIDS and reported prevalence of any risk factors were extracted using customized data extraction forms in Covidence.

Results

Our analysis rested on 32 peer-reviewed articles. Nine studies presented prevalence estimates on bedsharing and prone sleeping, suggesting near-universal bedsharing of infants with parents (range, 60 to 91.8%) and frequent use of the prone sleeping position (range, 26.7 to 63.8%). Eleven studies reported on the prevalence of SIDS, suggesting high rates of SIDS in Africa. The prevalence of SIDS ranged from 3.7 per 1000 live births in South Africa, 2.5 per 1000 live births in Niger, and 0.2 per 1000 live births in Zimbabwe. SIDS and other sudden infant deaths accounted for between 2.5 to 21% of infant deaths in South Africa and 11.3% in Zambia.

Conclusions

Africa may have the highest global rate of SIDS with a high burden of associated risk factors. However, majority of the studies were from South Africa which limits generalizability of our findings to the entire continent. There is an urgent need for higher quality studies outside of South Africa to fill this knowledge gap.

Protocol registration

Prospero Registration Number: CRD42021257261

Half Century Since SIDS: A Reappraisal of Terminology

After a sudden infant death, parents and caregivers need accurate and open communication about why their infant died. Communicating tragic news about a child's death to families and caregivers is difficult. Shared and consistent terminology is essential for pediatricians, other physicians, and nonphysician clinicians to improve communication with families and among themselves. When families do not have complete information about why their child died, pediatricians will not be able to support them through the process and make appropriate referrals for pediatric specialty and mental health care. Families can only speculate about the cause and may blame themselves or others for the infant's death. The terminology used to describe infant deaths that occur suddenly and unexpectedly includes an assortment of terms that vary across and among pediatrician, other physician, or nonphysician clinician disciplines. Having consistent terminology is critical to improve the understanding of the etiology, pathophysiology, and epidemiology of these deaths and communicate with families. A lack of consistent terminology also makes it difficult to reliably monitor trends in mortality and hampers the ability to develop effective interventions. This report describes the history of sudden infant death terminology and summarizes the debate over the terminology and the resulting diagnostic shift of these deaths. This information is to assist pediatricians, other physicians, and nonphysician clinicians in caring for families during this difficult time. The importance of consistent terminology is outlined, followed by a summary of progress toward consensus. Recommendations for pediatricians, other physicians, and nonphysician clinicians are proposed.

Explaining Sudden Unexpected Infant Deaths, 2011-2017

BACKGROUND

Sudden unexpected infant death (SUID) represents a broad group of explained and unexplained infant deaths (<1 year old). Explaining why SUID occurs is critical to understanding etiology and prevention. Death certificate data cannot differentiate explained from unexplained SUID cases nor describe the surrounding circumstances. We report SUID rates by explained and unexplained categories and describe demographics and history of recent injury or illness using the Centers for Disease Control and Prevention SUID Case Registry.

METHODS

The registry is a population-based surveillance system built on Child Death Review programs. Data are derived from multiple sources, including death certificates, scene investigations, and autopsy reports. Cases included SUIDs reported by states or jurisdictions participating in the registry during 2011-2017. Cases were classified into explained and unexplained categories by using the registry's classification system. Frequencies, percentages, and mortality rates per 100 000 live births were calculated.

RESULTS

Of the 4929 SUID cases, 82% were categorized as unexplained. Among all cases, 73% had complete case information. Most SUIDs (72%) occurred in an unsafe sleep environment. The SUID mortality rate was 97.3 per 100 000 live births. Among explained and possible suffocation deaths, ∼75% resulted from airway obstruction attributed to soft bedding.

CONCLUSIONS

Unsafe sleep factors were common in explained and unexplained SUID cases, but deaths could only be classified as explained suffocation for ∼20% of cases. Further analysis of unexplained deaths, including continued improvements to death scene investigation and documentation, may generate hypotheses for physiologic and genetic research, advance our understanding of gaps in SUID investigation, and enhance our understanding of infants at highest risk.

A retrospective study of death scene investigation practices for sudden unexpected death of infants (SUDI) in Cape Town, South Africa

A death scene investigation (DSI) forms an integral part of the inquiry into death, particularly for sudden unexpected death of infants (SUDI). Global guidelines exist for DSI, however, previous studies have shown that South Africa does not routinely perform DSI for SUDI cases, nor is there a standard protocol in this regard. This was largely attributed to the large burden of SUDI cases as well as the lack of resources, due to South Africa being a developing country. This study assessed DSI practices at one of the largest mortuaries in Cape Town (Salt River Mortuary) to assess the scope of these practices within a resource-constrained context. Data were collected by retrospectively reviewing medico-legal case files (n = 454) from SUDI cases investigated at Salt River Mortuary over a two-year period. The results showed that SUDI death scenes were visited in 59.2% of cases at Salt River Mortuary, with poor and inconsistent levels of documentation. Death scenes were never investigated in cases where the infant was pronounced dead on arrival at a medical facility. The findings support the need for a locally relevant approach to DSI, coupled with specialized training for staff. Based on the limited resources, this should focus on the training of staff using the available resources and accurate use of documentation.

Inconsistent classification of unexplained sudden deaths in infants and children hinders surveillance, prevention and research: recommendations from The 3rd International Congress on Sudden Infant and Child Death

This report details the proceedings and conclusions from the 3rd International Congress on Unexplained Deaths in Infants and Children, held November 26–27, 2018 at the Radcliffe Institute at Harvard University. The Congress was motivated by the increasing rejection of the diagnosis Sudden Infant Death Syndrome (SIDS) in the medical examiner community, leading to falsely depressed reported SIDS rates and undermining the validity and reliability of the diagnosis, which remains a leading cause of infant and child mortality. We describe the diagnostic shift away from SIDS and the practical issues contributing to it. The Congress was attended by major figures and opinion leaders in this area from countries significantly engaged in this problem. Four categories (International Classification of Diseases (ICD)-11 categories of MH11, MH12, MH14, PB00-PB0Z) were recommended for classification, and explicit definitions and guidance were provided for death certifiers. SIDS was reframed as unexplained sudden death in infancy or SIDS/MH11 to emphasize that either term signifies the lack of explanation following a rigorous investigation. A distinct category for children over the age of 1 was recommended (MH12). Definitions and exclusions were provided for the alternative categories of accidental asphyxia and undetermined. As recommended, unexplained sudden death in infancy or SIDS on a death certificate will code a unique, trackable entity, accurately reflecting the inability to determine a definitive explanation, while satisfying surveillance needs and reliable identification for research efforts. The conclusions will be submitted to the World Health Organization for inclusion in the upcoming ICD-11.

The Institution of a Standardized Investigation Protocol for Sudden Infant Death in the Eastern Metropole, Cape Town, South Africa,. J Forensic Sci 2016;61:1508-1514. [PMID: 27677096 DOI: 10.1111/1556-4029.13204]

The rate for the sudden infant death syndrome (SIDS) in Cape Town, South Africa, is estimated to be among the highest in the world (3.41/1000 live births). In several of these areas, including those of extreme poverty, only sporadic, nonstandardized infant autopsy, and death scene investigation (DSI) occurred. In this report, we detail a feasibility project comprising 18 autopsied infants with sudden and unexpected death whose causes of death were adjudicated according to the 1991 NICHD definitions (SIDS, n = 7; known cause of death, n = 7; and unclassified, n = 4). We instituted a standardized autopsy and infant DSI through a collaborative effort of local forensic pathology officers and clinical providers. The high standard of forensic investigation met international standards, identified preventable disease, and allowed for incorporation of research. We conclude that an effective infant autopsy and DSI protocol can be established in areas with both high sudden unexpected infant death, and elsewhere. (SUID)/SIDS risk and infrastructure challenges.

Parent-child bed-sharing: The good, the bad, and the burden of evidence

The practice of parent and child sharing a sleeping surface, or 'bed-sharing', is one of the most controversial topics in parenting research. The lay literature has popularized and polarized this debate, offering on one hand claims of dangers, and on the other, of benefits - both physical and psychological - associated with bed-sharing. To address the scientific evidence behind such claims, we systematically reviewed 659 published papers (peer-reviewed, editorial pieces, and commentaries) on the topic of parent-child bed-sharing. Our review offers a narrative walkthrough of the many subdomains of bed-sharing research, including its many correlates (e.g., socioeconomic and cultural factors) and purported risks or outcomes (e.g., sudden infant death syndrome, sleep problems). We found general design limitations and a lack of convincing evidence in the literature, which preclude making strong generalizations. A heat-map based on 98 eligible studies aids the reader to visualize world-wide prevalence in bed-sharing and highlights the need for further research in societies where bed-sharing is the norm. We urge for multiple subfields - anthropology, psychology/psychiatry, and pediatrics - to come together with the aim of understanding infant sleep and how nightly proximity to the parents influences children's social, emotional, and physical development.

Measurement of nucleated red blood cells in the peripheral blood as a marker of hypoxia in sudden unexpected death in infancy

AIMS

A recently proposed classification of sudden unexpected infant death incorporates consideration of possibly asphyxia. This depends on an adequate postmortem, scene investigation and history. A reliable marker of asphyxia has yet to be identified. Such a marker could assist in classifying these deaths. Our aim was to determine if the level of nucleated red blood cells (nRBCs) in the peripheral blood could help identify those possibly asphyxia-related deaths and if risk factors could influence this level in the peripheral blood.

METHODS

Cases of sudden unexpected deaths in infancy and sudden infant death syndrome (SIDS) which occurred over a period of 6 years (2007-2013) and were autopsied at Sheffield Children's Hospital were reviewed and categorised according to a new classification proposed by Randall et al. The cases were then correlated with the blood level of nRBCs determined at the time of post mortem examination. The study was approved by the Clinical Governance Department, number SE331.

RESULTS

139 deaths were classified into Group A (true SIDS, 67 cases), Group B (possible asphyxia related, 24 cases), Group C (non-asphyxia-related, 6 cases), Group D (no crime scene investigation, 0 cases) and Group E (identifiable cause, 42 cases). The levels were significantly increased in ex-premature babies, in infants with an underlying condition (Group C) and in deaths related to illness or trauma (Group E). There was a trend towards higher levels of nRBCs in younger age groups and in babies born to smoking mothers.

CONCLUSIONS

SIDS remains a difficult diagnosis to make despite the current medical technological advances where no marker of hypoxia has yet been identified.

Assigning cause for sudden unexpected infant death

We have reached a conundrum in assigning cause of death for sudden unexpected infant deaths. We summarize the discordant perspectives and approaches and how they have occurred, and recommend a pathway toward improved consistency. This lack of consistency affects pediatricians and other health care professionals, scientific investigators, medical examiners and coroners, law enforcement agencies, families, and support or advocacy groups. We recommend that an interdisciplinary international committee be organized to review current approaches for assigning cause of death, and to identify a consensus strategy for improving consistency. This effort will need to encompass intrinsic risk factors or infant vulnerability in addition to known environmental risk factors including unsafe sleep settings, and must be sufficiently flexible to accommodate a progressively expanding knowledge base.

Dentate gyrus abnormalities in sudden unexplained death in infants: morphological marker of underlying brain vulnerability

Sudden unexplained death in infants, including the sudden infant death syndrome, is likely due to heterogeneous causes that involve different intrinsic vulnerabilities and/or environmental factors. Neuropathologic research focuses upon the role of brain regions, particularly the brainstem, that regulate or modulate autonomic and respiratory control during sleep or transitions to waking. The hippocampus is a key component of the forebrain-limbic network that modulates autonomic/respiratory control via brainstem connections, but its role in sudden infant death has received little attention. We tested the hypothesis that a well-established marker of hippocampal pathology in temporal lobe epilepsy-focal granule cell bilamination in the dentate, a variant of granule cell dispersion-is associated with sudden unexplained death in infants. In a blinded study of hippocampal morphology in 153 infants with sudden and unexpected death autopsied in the San Diego County medical examiner's office, deaths were classified as unexplained or explained based upon autopsy and scene investigation. Focal granule cell bilamination was present in 41.2% (47/114) of the unexplained group compared to 7.7% (3/39) of the explained (control) group (p < 0.001). It was associated with a cluster of other dentate developmental abnormalities that reflect defective neuronal proliferation, migration, and/or survival. Dentate lesions in a large subset of infants with sudden unexplained death may represent a developmental vulnerability that leads to autonomic/respiratory instability or autonomic seizures, and sleep-related death when the infants are challenged with homeostatic stressors. Importantly, these lesions can be recognized in microscopic sections prepared in current forensic practice. Future research is needed to determine the relationship between hippocampal and previously reported brainstem pathology in sudden infant death.

Infectious causes of sudden infant death syndrome

Investigators have long suspected the role of infection in sudden infant death syndrome (SIDS). Evidence of infectious associations with SIDS is accentuated through the presence of markers of infection and inflammation on autopsy of SIDS infants and isolates of some bacteria and viruses. Several observational studies have looked into the relation between seasonality and incidence of SIDS, which often showed a winter peak. These all may suggest an infectious aetiology of SIDS. In this review we have summarised the current literature on infectious aetiologies of SIDS by looking at viral, bacterial, genetic and environmental factors which are believed to be associated with SIDS.

The safe passage study: design, methods, recruitment, and follow-up approach

BACKGROUND

The Safe Passage Study is a large, prospective, multidisciplinary study designed to (1) investigate the association between prenatal alcohol exposure, sudden infant death syndrome (SIDS), and stillbirth, and (2) determine the biological basis of the spectrum of phenotypic outcomes from exposure, as modified by environmental and genetic factors that increase the risk of stillbirth, SIDS, and in surviving children, fetal alcohol spectrum disorders.

METHODS

The results provided are based on an interim assessment of 6004 women enrolled, out of the 12,000 projected, from the Northern Plains, US, and Cape Town, South Africa, areas known to be of high risk for maternal drinking during pregnancy. Research objectives, study design, and descriptive statistics, including consent, recruitment, and retention information, are provided.

RESULTS

Overall visit compliance is 87%, and includes prenatal, delivery/newborn, and postnatal contacts through 1 year post-delivery. Pregnancy outcome ascertainment is 98% prior to medical chart review; less than 2% of women withdraw. Consent for the use of DNA and placental tissue exceed 94%, and consent to participate in the autopsy portion of the study is 71%.

CONCLUSIONS

The Safe Passage Study is the first multi-site study of SIDS and stillbirth to integrate prospectively collected exposure information with multidisciplinary biological information in the same maternal and fetal/infant dyad using a common protocol. Essential components of the study design and its success are close ties to the community and rigorous systems and processes to ensure compliance with the study protocol and procedures.

Classification system for the Sudden Unexpected Infant Death Case Registry and its application

Sudden unexpected infant deaths (SUID) accounted for 1 in 3 postneonatal deaths in 2010. Sudden infant death syndrome and accidental sleep-related suffocation are among the most frequently reported types of SUID. The causes of these SUID usually are not obvious before a medico-legal investigation and may remain unexplained even after investigation. Lack of consistent investigation practices and an autopsy marker make it difficult to distinguish sudden infant death syndrome from other SUID. Standardized categories might assist in differentiating SUID subtypes and allow for more accurate monitoring of the magnitude of SUID, as well as an enhanced ability to characterize the highest risk groups. To capture information about the extent to which cases are thoroughly investigated and how factors like unsafe sleep may contribute to deaths, CDC created a multistate SUID Case Registry in 2009. As part of the registry, the Centers for Disease Control and Prevention developed a classification system that recognizes the uncertainty about how suffocation or asphyxiation may contribute to death and that accounts for unknown and incomplete information about the death scene and autopsy. This report describes the classification system, including its definitions and decision-making algorithm, and applies the system to 436 US SUID cases that occurred in 2011 and were reported to the registry. These categories, although not replacing official cause-of-death determinations, allow local and state programs to track SUID subtypes, creating a valuable tool to identify gaps in investigation and inform SUID reduction strategies.

Potential asphyxia and brainstem abnormalities in sudden and unexpected death in infants

OBJECTIVE

Sudden and unexplained death is a leading cause of infant mortality. Certain characteristics of the sleep environment increase the risk for sleep-related sudden and unexplained infant death. These characteristics have the potential to generate asphyxial conditions. We tested the hypothesis that infants may be exposed to differing degrees of asphyxia in sleep environments, such that vulnerable infants with a severe underlying brainstem deficiency in serotonergic, γ-aminobutyric acid-ergic, or 14-3-3 transduction proteins succumb even without asphyxial triggers (e.g., supine), whereas infants with intermediate or borderline brainstem deficiencies require asphyxial stressors to precipitate death.

METHODS

We classified cases of sudden infant death into categories relative to a "potential asphyxia" schema in a cohort autopsied at the San Diego County Medical Examiner's Office. Controls were infants who died with known causes of death established at autopsy. Analysis of covariance tested for differences between groups.

RESULTS

Medullary neurochemical abnormalities were present in both infants dying suddenly in circumstances consistent with asphyxia and infants dying suddenly without obvious asphyxia-generating circumstances. There were no differences in the mean neurochemical measures between these 2 groups, although mean measures were both significantly lower (P < .05) than those of controls dying of known causes.

CONCLUSIONS

We found no direct relationship between the presence of potentially asphyxia conditions in the sleep environment and brainstem abnormalities in infants dying suddenly and unexpectedly. Brainstem abnormalities were associated with both asphyxia-generating and non-asphyxia generating conditions. Heeding safe sleep messages is essential for all infants, especially given our current inability to detect underlying vulnerabilities.

Sudden twin infant death on the same day: a case report and review of the literature

Sudden infant death syndrome (SIDS) is a major contributor to infant mortality. The cause of death is unknown: suggested possibilities include cardiovascular disease, anaphylactic shock, and suffocation. The occurrence of simultaneous sudden infant death syndrome is uncommon, such cases being extremely rare in forensic pathologic practice. We report two 10-week-old male twins who appeared well at the time of their evening feeding, yet died while sleeping on their backs. Both infants had petechial hemorrhages on the visceral pleura, epicardial surface of the heart, and thymus gland. Microscopic examination revealed pulmonary edema, intra-alveolar hemorrhage, and minor lymphocytic infiltration, again in both infants. In this report, we discuss the risk factors for SIDS, which should be considered individually or in combination as possible causes of death.

Application of a classification system focusing on potential asphyxia for cases of sudden unexpected infant death

Current classification schemes for sudden unexpected infant death (SUID) may not be optimal for capturing scene events that potentially predispose to asphyxia. (1) To compare causes of death in a group of SUID cases assigned by multiple reviewers using our recently published classification scheme for SUID that is based on asphyxial risk at the death scene, and (2) To compare these newly assigned causes of death to that originally assigned by the medical examiners of record who performed the autopsies. Five reviewers independently assigned causes of death for 117 cases of SUID, including 83 originally diagnosed as sudden infant death syndrome (SIDS), accessioned into the San Diego SIDS/SUDC Research Project from the San Diego County Medical Examiner's Office. The diagnostic categories are: A: SIDS; B: Unexplained-Potentially Asphyxia; C: Unexplained-Other Potential Causes of Death; D: Unclassified-Other; E: Unclassified; and F: Known Cause of Death. The reviewers collectively opined that conditions at the death scene contributed to or caused death in 32-50% of all of the 117 cases as well as in 40-59% of the 83 originally diagnosed SIDS cases. Another cause of death was considered plausible in 2-12% of the SIDS cases. Application of this new classification system resulted in 55-69% decrease in SIDS diagnoses. Asphyxia as a potential contributor to, or as the specific cause of death, appears to exist in a large percentage of cases designated as SIDS using other classification schemes. When certifiers use a classification system that focuses upon potential asphyxia in determining the cause of death the incidence of SIDS dramatically declines.

The medico-legal investigation of sudden, unexpected and/or unexplained infant deaths in South Africa: where are we--and where are we going?

Sudden Infant Death Syndrome (SIDS) has been reported to be the leading cause of death in infants under 1 year of age in many countries. Unfortunately, a paucity of published research data exists in South Africa, with regard to the incidence of and investigation into the circumstances surrounding Sudden Unexplained Deaths in Infants (SUDI) and/or SIDS. Currently, even though most academic centers conform to a protocol consistent with internationally accepted standards, there exists no nationally accepted infant death investigation protocol in South Africa. It is the aim of this study to review the current practice of infant death investigation in two representative but geographically and demographically distinct centers. Retrospective case audit over a five-year period (2000-2004) was conducted at two large medico-legal mortuaries in Pretoria (Gauteng) and Tygerberg (Cape Town). Case files on all infants younger than 1 year of age were reviewed. The outcome measures included number of deaths, demographic details and the nature and final outcome of the post mortem examinations. A total of 512 cases were identified as possible SIDS cases and of these, 171 was classified as SIDS. The study showed marked inter-case and inter-divisional variation in terms of the investigation of infant deaths at the two institutions. It is envisaged that this study will focus attention on the current lack of usable data regarding sudden/unexplained/unexpected infant deaths in South Africa, and aid in the formulation and implementation of a practical (yet internationally accountable) infant death investigation protocol, which could facilitate comparisons with other countries and initiate further structured research in this field.