Sleep-related Deaths Research Articles

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.Electronic supplementary materialThe online version of this article (doi:10.1007/s00401-014-1357-0) contains supplementary material, which is available to authorized users.

Sofas and infant mortality.

Sleeping on sofas increases the risk of sudden infant death syndrome and other sleep-related deaths. We sought to describe factors associated with infant deaths on sofas. We analyzed data for infant deaths on sofas from 24 states in 2004 to 2012 in the National Center for the Review and Prevention of Child Deaths Case Reporting System database. Demographic and environmental data for deaths on sofas were compared with data for sleep-related infant deaths in other locations, using bivariate and multivariable, multinomial logistic regression analyses. A total of 1024 deaths on sofas made up 12.9% of sleep-related infant deaths. They were more likely than deaths in other locations to be classified as accidental suffocation or strangulation (adjusted odds ratio [aOR] 1.9; 95% confidence interval [CI], 1.6-2.3) or ill-defined cause of death (aOR 1.2; 95% CI, 1.0-1.5). Infants who died on sofas were less likely to be Hispanic (aOR 0.7; 95% CI, 0.6-0.9) compared with non-Hispanic white infants or to have objects in the environment (aOR 0.6; 95% CI, 0.5-0.7) and more likely to be sharing the surface with another person (aOR 2.4; 95% CI, 1.9-3.0), to be found on the side (aOR 1.9; 95% CI, 1.4-2.4), to be found in a new sleep location (aOR 6.5; 95% CI, 5.2-8.2), and to have had prenatal smoke exposure (aOR 1.4; 95% CI, 1.2-1.6). Data on recent parental alcohol and drug consumption were not available. The sofa is an extremely hazardous sleep surface for infants. Deaths on sofas are associated with surface sharing, being found on the side, changing sleep location, and experiencing prenatal tobacco exposure, which are all risk factors for sudden infant death syndrome and sleep-related deaths.

Exploring caregiver behavior and knowledge about unsafe sleep surfaces in infant injury death cases.

In the United States, infant deaths due to sleep-related injuries have quadrupled over the past two decades. One of the major risk factors is the placement of an infant to sleep on a surface other than a crib or bassinet. This study examines contextual circumstances and knowledge and behaviors that may contribute to the placement of infants on an unsafe sleep surface in infant injury death cases. This study employed a retrospective review of 255 sleep-related injury death cases in New York City from 2004 to 2010 where an infant was found sleeping on an unsafe sleep surface. Mixed-methods analyses, employing both quantitative analysis of vital statistics data and risk variables extracted from the medical examiner files and qualitative analysis of the narrative content of the files, were conducted. In 48% of cases, a crib or bassinet was identified in the home. Quantitative analysis revealed no significant differences in demographic or risk factor characteristics between infants who had a crib or bassinet and those who did not. Qualitative analysis highlighted factors in caregivers' decision making related to situational convenience, preference, and misconceptions concerning safe infant sleep. The health belief model (HBM), specifically the constructs of perceived susceptibility, severity, benefits, and barriers, was used as a lens to understand factors associated with caregiver behavior. This study provides evidence that infants are at risk of sleep-related injury death even when a crib or bassinet is present. Understanding the factors that may influence safe sleep behaviors can help produce more appropriate interventions.

Risk Factors Differ for Sleep-Related Deaths in Younger and Older Infants

Although the incidence of sudden infant death syndrome (SIDS) has declined since 2000, rates of other sleep-related infant deaths (e.g., accidental suffocation, asphyxiation) have increased. In 2011, the American Academy of Pediatrics published recommendations for a safe infant sleep environment (NEJM JW Pediatr Adolesc Med Nov 16 2011). To examine risk factors …

Knowledge and beliefs of African-American and American Indian parents and supporters about infant safe sleep.

To investigate, by using qualitative methods, beliefs among African-American and American Indian families about infant safe sleep practices, barriers to acceptance of prevention recommendations, and more effective messaging strategies. Seventy-three mothers and supporters participated in focus groups. Participants discussed infant sleep practices and effectiveness of safe sleep messages. Data were coded, and themes were developed and revised in an iterative manner as patterns became more apparent. Themes included reasons for and influences on sleep decisions, and concerns about safe sleep recommendations. Parental sleep decisions seemed to be driven by perceptions of what would make their infant most comfortable and safe, and what would be most convenient. Parents were aware of safe sleep recommendations but unaware of the rationale. Because they generally did not believe that their infants were at risk for a sleep-related death, day-to-day decisions seemed to focus on what was most effective in getting their infant to sleep. There appeared to be no distinctions in opinions among African-American and American Indian families. African-American and American Indian families seemed to have similar concerns about infant comfort and safety, and their perceptions about what would be most effective in achieving these goals appeared to be important influences on their sleep practices. Adherence with safe sleep recommendations may be enhanced if health care providers and educational materials discussed rationale underlying recommendations and addressed common parental concerns. It may be beneficial to target educational interventions towards fathers, as they may be untapped sources in implementing safe sleep practices.

To Improve Safe Sleep, More Emphasis Should Be Placed on Removing Inappropriate Items From Cribs

INTRODUCTION: Current recommendations to prevent sleep-related death include that infants be placed on their back in a crib with a firm mattress and fitted sheet. Bumpers, pillows, loose blankets, stuffed toys, and other suffocation hazards are not recommended. However, sleep-related infant deaths continue to occur. As part of a university, physician, and nonprofit collaboration, a Safe Sleep Toolkit was developed to improve consistency in safe sleep communication. METHODS: The toolkit was implemented at two resident physician clinics, obstetric and pediatric, and included: 1) parent checklist regarding sleep position, location, environment, and intentions to share information; 2) a brief health care provider script; and 3) nationally available resources. Approval was received from two local institutional review boards. RESULTS: Checklists were completed by 309 parents, 64% at the pediatric and 36% at the obstetric clinic. The majority were female (83%) with a high school diploma or less (66%). Nearly half (48%) were white. Most parents reported appropriate sleep location (88%) and position (79%); however, only 37% reported no inappropriate items in the sleep environment. Health care providers engaged in discussion regarding safe sleep with most parents. CONCLUSIONS: Most parents were aware of and implementing the American Association of Pediatrics' recommendations for safe sleep location and position. However, more than 60% reported at least one item in the crib that would increase the infant's risk of accidental asphyxiation. Although this assessment has limitations in process and scope, our toolkit may assist in identifying gaps in parent knowledge and practice and may be useful in prompting health care provider communication regarding safe sleep. Language: en

Trends and factors associated with infant bed sharing, 1993-2010: the National Infant Sleep Position Study.

A strong association between infant bed sharing and sudden infant death syndrome or unintentional sleep-related death in infants has been established. Occurrences of unintentional sleep-related deaths among infants appear to be increasing. To determine the trends and factors associated with infant bed sharing from 1993 through 2010, including the association of physician advice on bed sharing. National Infant Sleep Position study conducted with annual telephone surveys. The 48 contiguous states. Nighttime caregivers of infants born within 7 months of each survey administration. Approximately 1000 interviews were completed annually. Infant bed sharing as a usual practice. Of 18 986 participants, 11.2% reported an infant sharing a bed as a usual practice. Bed sharing increased from 1993 (6.5%) to 2010 (13.5%). Although bed sharing increased significantly among white respondents from 1993 to 2000 (P < .001), the increase from 2001 to 2010 was not significant (P = .48). Black and Hispanic respondents reported an increase in bed sharing throughout the study period, with no difference between the earlier and later periods (P = .63 and P = .77, respectively). After accounting for the study year, factors associated with increase in infant bed sharing as a usual practice included maternal educational level of less than high school compared with college or greater (adjusted odds ratio, 1.42 [95% CI, 1.12-1.79]); black (3.47 [2.97-4.05]), Hispanic (1.33 [1.10-1.61]), and other (2.46 [2.03-2.97]) maternal race or ethnicity compared with white race; household income of less than $20,000 (1.69 [1.44-1.99]) and $20,000 to $50,000 (1.29 [1.14-1.45]) compared with greater than $50,000; living in the West (1.61 [1.38-1.88]) or the South (1.47 [1.30-1.66]) compared with the Midwest; infants younger than 8 weeks (1.45 [1.21-1.73]) or ages 8 to 15 weeks (1.31 [1.17-1.45]) compared with 16 weeks or older; and being born prematurely compared with full-term (1.41 [1.22-1.62]). Almost 46% of the participants reported talking to a physician about bed sharing. Compared with those who did not receive advice from a physician, those who reported their physicians had a negative attitude were less likely to have the infant share a bed (adjusted odds ratio, 0.66 [95% CI, 0.53-0.82]), whereas a neutral attitude was associated with increased bed sharing (1.38 [1.05-1.80]). Our finding of a continual increase in bed sharing throughout the study period among black and Hispanic infants suggests that the current American Academy of Pediatrics recommendation about bed sharing is not universally followed. The factors associated with infant bed sharing may be useful in evaluating the impact of a broad intervention to change behavior.

The Role of Cosmetologists as Health Promoters in the Prevention of Infant Mortality

Safe sleep practices reduce an infant's risk for sudden infant death syndrome and sleep-related death. While rates of infants placed on their back to sleep are high, other safe sleep practices are less widely implemented. Our objective was to evaluate the feasibility of using cosmetologists as health promoters for infant safe sleep to reduce infant mortality. In this descriptive study, a 27-item survey was mailed to the 405 licensed cosmetologists residing in the five zip codes with the highest infant mortality rates in the county. Of 149 completed surveys (36.8 %), 103 cosmetologists (69.1 %) were currently working. Most were comfortable (68.9 %) promoting health topics with their clients. Popular health-related topics currently discussed included: diet/weight control, healthy eating, and physical activity. Few (≤13 %) were interested in discussing infant mortality prevention or safe sleep promotion. Most respondents were either unsure (56 %) or did not feel infant mortality was a problem in their community (41 %); however, more than half (53 %) knew someone who had experienced an infant death. Cosmetologists were not highly interested in providing safe sleep education; however they engaged in diet and exercise talk already. Cosmetologists may be more appropriate for obesity-prevention programs to reduce infant mortality than safe sleep promotion.

Improving Safe Sleep Environments for Well Newborns in the Hospital Setting

Following the "Back to Sleep" campaign, deaths from sudden infant death syndrome (SIDS) were reduced. However, SIDS and sleep-related deaths continue to occur. Studies demonstrate that modeling by health care workers influences parents to place infants supine for sleep. Recently, additional emphasis has been placed on environment. The purpose of this study was to improve sleep position and environment in the hospital. A Plan-Do-Study-Act cycle was initiated. Sleeping infants were observed at baseline. A bundled intervention was implemented; infants were again observed. Parents were surveyed. At baseline, 25% (36/144) of sleeping infants were safe; the majority of unsafe sleep was a result of environment. Postintervention, significantly more (58%; 145/249) had safe sleep (P < .0001). Most parents planned to use the supine position (95%; 96/101); none planned to cosleep. Many intended to adjust their infants' home sleep environment. Using a multifaceted approach significantly improved infant safe sleep practice in the hospital setting.

Socioeconomic Factors Affecting Infant Sleep‐Related Deaths in St. Louis

Though the Back to Sleep Campaign that began in 1994 caused an overall decrease in sudden infant death syndrome (SIDS) rates, racial disparity has continued to increase in St. Louis. Though researchers have analyzed and described various sociodemographic characteristics of SIDS and infant deaths by unintentional suffocation in St. Louis, they have not simultaneously controlled for contributory risk factors to racial disparity such as race, poverty, maternal education, and number of children born to each mother (parity). To determine whether there is a relationship between maternal socioeconomic factors and sleep-related infant death. This quantitative case-control study used secondary data collected by the Missouri Department of Health and Senior Services between 2005 and 2009. The sample includes matched birth/death certificates and living birth certificates of infants who were born/died within time frame. Descriptive analysis, Chi-square, and logistic regression. The controls were birth records of infants who lived more than 1 year. Chi-square and logistic regression analyses confirmed that race and poverty have significant relationships with infant sleep-related deaths. The social significance of this study is that the results may lead to population-specific modifications of prevention messages that will reduce infant sleep-related deaths.

Now I lay you down to sleep: reducing suffocation risk in the infant sleep environment

BackgroundSuffocation is the leading cause of injury death among infants in the USA. Infant suffocation mortality rates increased from 2.8 to 12.5 deaths/100 000 live births between 1984 and 2004....

Explaining Sudden Unexplained Death

Sudden unexplained death (SUD) of the young is the term used for sudden deaths occurring before the age of 40 years, which remain unexplained despite analysis of all available antemortem information (usually because the victims had no family history of heart disease or warning symptoms) and a postmortem examination that was unrevealing or was not performed.1–3 For the surviving family members, the fact that the tragic death of a previously healthy relative remains unexplained only adds frustration and confusion to grief.4 Furthermore, because arrhythmic death in the young is often caused by familial diseases, reaching the correct diagnosis is important for those left behind, who may then receive appropriate prophylactic measures. Therefore, it is good clinical practice to systematically evaluate families of SUD victims in attempts to minimize the unexplained. Having said that, it is also important that family members considering screening be aware of the potential negative consequences associated with the diagnosis of an asymptomatic inheritable disease. Unjustified remorse or recrimination may torment parents of a deceased child, whereas unforeseen anxiety or disqualification from sports or life insurance policies may become problematic for asymptomatic, yet affected, siblings.5 A 1%/year risk of sudden death, as currently estimated for asymptomatic individuals with Brugada syndrome discovered through screening,6 may be perceived as reassuring by some but may be terrifying to others. Article see p 933 Evaluation of SUD families should begin with a meticulous review of available data concerning the index SUD victim. The circumstances of death are important: sleep-related death favors long-QT syndrome (LQTS) of the LQT3 type, short-QT syndrome, or Brugada syndrome (if male); sudden death during stress favors coronary disease (congenital coronary anomalies or premature atherosclerosis), cardiomyopathies, catecholaminergic polymorphic ventricular tachycardia (CPVT), or LQTS, whereas unexplained drowning favors LQT1 and CPVT.7 Favoring …

SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment

Despite a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed for sleep in a nonprone position, this decline has plateaued in recent years. Concurrently, other causes of sudden unexpected infant death occurring during sleep (sleep-related deaths), including suffocation, asphyxia, and entrapment, and ill-defined or unspecified causes of death have increased in incidence, particularly since the AAP published its last statement on SIDS in 2005. It has become increasingly important to address these other causes of sleep-related infant death. Many of the modifiable and nonmodifiable risk factors for SIDS and suffocation are strikingly similar. The AAP, therefore, is expanding its recommendations from being only SIDS-focused to focusing on a safe sleep environment that can reduce the risk of all sleep-related infant deaths including SIDS. The recommendations described in this report include supine positioning, use of a firm sleep surface, breastfeeding, room-sharing without bed-sharing, routine immunization, consideration of a pacifier, and avoidance of soft bedding, overheating, and exposure to tobacco smoke, alcohol, and illicit drugs. The rationale for these recommendations is discussed in detail in this technical report. The recommendations are published in the accompanying "Policy Statement--Sudden Infant Death Syndrome and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment," which is included in this issue (www.pediatrics.org/cgi/doi/10.1542/peds.2011-2220).

SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment

Despite a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed for sleep in a nonprone position, this decline has plateaued in recent years. Concurrently, other causes of sudden unexpected infant death that occur during sleep (sleep-related deaths), including suffocation, asphyxia, and entrapment, and ill-defined or unspecified causes of death have increased in incidence, particularly since the AAP published its last statement on SIDS in 2005. It has become increasingly important to address these other causes of sleep-related infant death. Many of the modifiable and nonmodifiable risk factors for SIDS and suffocation are strikingly similar. The AAP, therefore, is expanding its recommendations from focusing only on SIDS to focusing on a safe sleep environment that can reduce the risk of all sleep-related infant deaths, including SIDS. The recommendations described in this policy statement include supine positioning, use of a firm sleep surface, breastfeeding, room-sharing without bed-sharing, routine immunizations, consideration of using a pacifier, and avoidance of soft bedding, overheating, and exposure to tobacco smoke, alcohol, and illicit drugs. The rationale for these recommendations is discussed in detail in the accompanying "Technical Report--SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment," which is included in this issue of Pediatrics (www.pediatrics.org/cgi/content/full/128/5/e1341).

Reducing Infant Sleep-Related Deaths: An Urban County Initiative

Reducing Infant Sleep-Related Deaths: An Urban County Initiative

Sudden Death, Febrile Seizures, and Hippocampal and Temporal Lobe Maldevelopment in Toddlers: A New Entity

Recently, we reported hippocampal and temporal lobe abnormalities in 5 toddlers with sudden unexplained death in childhood (SUDC). The association of these anomalies with a high incidence (40%) of individual/family histories of simple febrile seizures in the cases raised concern that febrile seizures can be associated with death. In a series of 64 toddlers with sudden death, we tested the hypothesis that an SUDC subset is characterized by hippocampal and temporal lobe maldevelopment and an individual and/or family history of simple familial seizures. Cases of sudden and unexplained death in children aged 1.0 to 5.9 years (median 1.7 years) were divided into groups based upon a history of febrile or nonfebrile seizures, familial febrile seizures, and autopsy classification of cause of death. Forty-nine of the 64 cases (77%) were classified as SUDC, of which 40% had an individual/family history of febrile seizures. Of the 26 SUDC cases with available hippocampal sections, 62% (16/26) had hippocampal and temporal lobe anomalies, including 82% (9/11) of cases with an individual/family history of febrile seizures. Cases with these anomalies were all found dead during a sleep period, typically in the prone (87%) position. We conclude that a potential new entity may account for the majority of SUDC in toddlers, defined by sleep-related death in the prone position, individual/family history of febrile seizures, and hippocampal and temporal lobe anomalies. The mechanism of death appears analogous to sudden death in (temporal lobe) epilepsy, with a putative unwitnessed seizure during sleep leading to airway occlusion and death. This study mandates further research into the potential link between simple febrile seizures and death.

Interleukin-6 and the serotonergic system of the medulla oblongata in the sudden infant death syndrome

Mild infection may trigger sudden death in the vulnerable infant by cytokine interactions with a compromised medullary serotonergic (5-HT) system, leading to disrupted cardiorespiratory regulation and sleep-related sudden death. The cytokine interleukin (IL)-6 is elevated in the cerebrospinal fluid in SIDS. We tested the hypothesis that the expression of IL-6 receptors (IL-6R) and/or gp130 (involved in IL-6R signaling) is altered in the medullary 5-HT system in SIDS. Immunohistochemistry of IL-6R and gp130 was performed on medullae from 25 SIDS infants, 20 infectious deaths, and 14 controls using a semi-quantitative grading system. In the SIDS cases, mean IL-6R intensity grade in the arcuate nucleus (major component of medullary 5-HT system) was significantly higher than in the control group (2.00 +/- 0.07 vs. 1.77 +/- 0.08, P = 0.04), with no other differences in IL-6R or gp130 expression at any other site. Arcuate 5-HT neurons expressed IL-6R, indicating a site of IL-6/5-HT interaction. In SIDS, IL-6R expression is abnormal in the arcuate nucleus, the putative human homolog of rodent ventral medullary chemosensitivity sites involving 5-HT. Aberrant interactions between IL-6 and the arcuate nucleus may contribute to impaired responses to hypercapnia generated by infection (hyper-metabolism) combined with rebreathing.

Neuropathology provides new insight in the pathogenesis of the sudden infant death syndrome

The sudden infant death syndrome (SIDS) is deWned as the sudden, sleep-related death of an infant less than 12 months of age that remains unexplained after a complete autopsy, death scene investigation, and review of the clinical history [35]. Typically, a seemingly healthy infant is unexpectedly found dead after a sleep period. Despite a dramatic reduction in the overall rate with national campaigns advocating the supine (back) sleep position [43], SIDS remains the leading cause of postneonatal infant mortality and the third leading cause of infant mortality in general in the United States today [43]. The brain has long been thought to play a critical role in the cause and pathogenesis of SIDS. The recent publication of three excellent articles on brain pathology in SIDS in Acta Neuropathologica indicates that brain research into this major pediatric disorder continues to be important in guiding all SIDS research. Basically, brain research in SIDS follows three directions: (1) analysis to determine a primary (neural) cause of death, (2) analysis to uncover secondary changes that points to the primary cause, either within the brain or in other organ systems, and (3) analysis to determine the age of onset of the chain of events—prenatally and/or postnatally—that results in sudden death in the vulnerable postnatal period. The search for a primary cause is driven by the hypothesis that SIDS is due to intrinsic abnormalities in brain regions critical for the control of arousal and/ or state-dependent respiratory and/or autonomic function that lead to sleep-related death which is precipitated by a homeostatic stressor within a susceptible age-range. Secondary changes in the brain are postulated to result mainly from hypoxia–ischemia complicating repetitive apnea and/or bradycardia prior to the lethal cardiorespiratory event, as well as during the lethal event itself. Finally, the brain disorder is postulated to be developmental in origin due to the parallel onset and occurrence of SIDS with the major critical period in human brain development, i.e., gestation through the Wrst year of life. Yet, despite the compelling rationale for a key role of the brain in SIDS, the brain looks normal under the light microscope, or at the very most, demonstrates seemingly trivial or nonspeciWc changes. Thus, the challenge for us as neuropathologists in the analysis of SIDS brains—as in the analysis of autistic and schizophrenic brains—is to uncover neurochemical, cellular, and/or molecular abnormalities with the right quantitative tools. The three recent SIDS studies in Acta Neuropathologica cover the spectrum of neuropathological directions in SIDS research with quantitative methodologies: (1) the search for the primary abnormality in the brainstem with the application of an antibody to the serotonin 1A (5-HT1A) receptor by Machaalani et al. [37], (2) the determination of secondary hypoxic–ischemic changes in the cerebral cortex and hippocampus with MAP2 immunostaining by Oehmichen et al. [49], and (3) the report of critical evidence for a developmental origin of brain pathology, i.e., increased leptomeningeal neurons in the brainstem by Rickert et al. [62]. In the following commentary, I highlight the new insights that these studies bring to our understanding of the brain’s role in SIDS in the context of previous neuropathologic and other SIDS studies. H. C. Kinney (&) Department of Pathology, Enders Building 1112, Children’s Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA e-mail: Hannah.kinney@childrens.harvard.edu

Sudden cardiac death due to acute right heart failure in a patient with arrhythmogenic right ventricular dysplasia and acute myocardial infarction

A 40-year-old patient with toothache and shoulder pain for 10 days died without former known history of cardiac arrhythmias or myocardial infarction (MI) on sleep-related sudden cardiac death (SCD). The autopsy did not reveal signs for traumatic violence or intoxications nor for acute/chronic infections particularly of the upper aerodigestive tract. Furthermore, no aspects of endo-/myocarditis …

Subtle Autonomic and Respiratory Dysfunction in Sudden Infant Death Syndrome Associated With Serotonergic Brainstem Abnormalities: A Case Report

Sudden infant death syndrome (SIDS) is characterized by a sleep-related death in a seemingly healthy infant. Previously, we reported abnormalities in the serotonergic (5-HT) system of the medulla in SIDS cases in 2 independent datasets, including in the Northern Plains American Indians. The medullary 5-HT system is composed of 5-HT neurons in the raphé, extra-raphé, and arcuate nucleus at the ventral surface. This system is thought to modulate respiratory and autonomic function, and thus abnormalities within it could potentially lead to imbalances in sympathetic and parasympathetic tone. We report the case of a full-term American Indian boy who died of SIDS at 2 postnatal weeks, and who had subtle respiratory and autonomic dysfunction measured prospectively on the second postnatal day. Cardiorespiratory assessment of heart rate variability suggested that the ratio of parasympathetic to sympathetic tone was higher than normal in active sleep and lower than normal in quiet sleep in this case. At autopsy, arcuate nucleus hypoplasia and 5-HT receptor-binding abnormalities in the arcuate nucleus and other components of the medullary 5-HT system were found. This case suggests that medullary 5-HT system abnormalities may be able to be identified by such physiological tests before death. Replication of these findings in a large population may lead to the development of predictive cardiorespiratory assessment tools for future screening to identify infants with medullary 5-HT abnormalities and SIDS risk.