Sudden infant death syndrome: a subject of medicolegal research

During the last decade, much attention has been paid to the risk factors of sudden infant death syndrome (SIDS). Many researchers have demonstrated that infant-care practices are linked to the risk of SIDS. Prone sleeping, bed sharing, maternal substance abuse, and cigarette smoking have been reported to be significant potentially modifiable risk factors for SIDS. Despite the reports that the incidence of SIDS has decreased by 38% in the United States, it remains the leading cause of death in the first year of life. Deaths resulting from child abuse or neglect inflicted or permitted by their caretakers being second only to SIDS in infant mortalities and some recommendations regarding the differentiation of SIDS and child abuse have generated speculation that some cases of infanticide were misdiagnosed as SIDS. To reach a proper conclusion as to the cause and manner of death of an infant who died suddenly and unexpectedly, investigation must be thorough and professional.     

Infant Death Following Home Birth: A Case Report of Fatal Neonatal Hypoglycemia

Infants born to diabetic mothers are at increased risk for symptomatic hypoglycemia and death after birth. A 36-year-old G4P3 mother with a history of gestational diabetes and newly diagnosed type II insulin-dependent diabetes gave birth at home, in the care of a midwife, to a macrosomic infant girl (10 lbs.). Several hours after birth, the infant became lethargic and was found to be hypoglycemic (blood sugar: 28 mg/dL). Glucose and sugar water were administered by the midwife; however, the infant continued to decompensate. Emergency medical services were called, and the infant was transported to the hospital where, despite resuscitative efforts, she died. An autopsy and review of the literature was performed. At autopsy, characteristic features of maternal–fetal glucose dysregulation were identified, including fetal macrosomia, cardiomegaly, hepatomegaly, and severe pancreatic islet cell hypertrophy/hyperplasia. Developmental abnormalities and other potential causes of death were not identified. Although deaths due to hypoglycemia cannot be reliably diagnosed postmortem using vitreous glucose levels, a clinical history of maternal glucose dysregulation in combination with certain gross and histologic findings should prompt a pathologist to consider maternal–fetal glucose dysregulation as a diagnosis of exclusion and cause of death.     

Prevalence of potential risk factors in victims of electrocution.

OBJECTIVE: To identify risk factors of fatal arrhythmia following electrical shock, by comparing the prevalence of transthoracic current, tetany, decreased skin resistance because of wet extremities, skin burns and heart disease in victims of electrocution with instant as opposed to delayed death. DESIGN: Retrospective case-control study, based on the charts from the coroner's office. RESULTS: A total of 124 deaths from electrocution occurred between 1987 and 1992. One victim presumably died from delayed arrhythmia and was excluded from the study. Twenty victims had decreased skin resistance because of wet extremities and five had tetany. Autopsy revealed coronary heart disease in 21 cases, and burns in 109; 10 did not have any skin lesion. There was no difference in risk factors between those who died instantly presumably from arrhythmia (n=114) and those who died later from other causes (n=9). CONCLUSION: No differences in risk factors were found between victims who died immediately from arrhythmia following electrical shock and those died later from other causes.     

Cosleeping and sudden unexpected infant deaths in Kentucky: a 10-year retrospective case review

This retrospective case review investigates modifiable risk factors in sudden unexpected infant deaths, including those attributed to sudden infant death syndrome, and examines the impact of cosleeping with adults or siblings. The study examines sudden unexpected infant deaths from 1991 to 2000 in the state of Kentucky, excluding homicides and deaths from identifiable natural causes. Meta-analysis provides a cosleeping prevalence control in normal infants. Based on the findings described herein, we conclude that cosleeping may represent a risk factor in sudden unexpected infant deaths and that a full scene investigation, including whether the infant was cosleeping, should be sought in all cases of sudden infant death.     

Battered woman syndrome testimony in Canada: its development and lingering issues

This article examines the status of battered woman syndrome (BWS) testimony in Canadian courts and assesses the impact of the leading decision, Regina (R.) v. Lavallee. Acknowledging the test of reasonableness in criminal trials was constructed on a male model, the Supreme Court in Lavallee corrected the gendered interpretation of women in abusive relationships by admitting the BWS evidence. Feminist legal scholars questioned whether Lavallee had succeeded in dispelling the stereotypes around battered women. These concerns were partially addressed in R. v. Malott, but some tough issues remain: applying the reasonableness test to women of color and the narrow base of BWS evidence. Some directions are discussed: discarding BWS testimony, framing a redefined and expanded BWS testimony, introducing a new defense based on self-preservation, and adopting an alternative interpretative frame such as "coercive control." The strengthening of BWS testimony would call for the judges' referencing of latest empirical research on battered women.     

Failure to detect elevated levels of carboxyhemoglobin in infants dying from SIDS

Carboxyhemoglobin (COHb) levels were determined in stored blood samples from 91 infants diagnosed to have died from the sudden infant death syndrome (SIDS) (0.59+/-0.41%, excluding one outlying value of 10.83%); 48 age-matched controls (0.53+/-0.38%); and three individuals who died from fire related causes (41+/-20%). No statistical differences in COHb levels were detected between blood from SIDS and control infants (p = 0.43).     

Beta-tryptase and quantitative mast-cell increase in a sudden infant death following hexavalent immunization

The association between sudden infant death syndrome and immunization is frequently discussed. Serious adverse events following vaccination have generally been defined as those adverse events that result in permanent disability, hospitalization or prolongation of hospitalization, life threatening illness, congenital anomaly or death. They are generally referred to the inherent properties of the vaccine (vaccine reaction) or some error in the immunization process (programme error). The event could also be totally unrelated but only temporally linked to immunization (coincidental event). A fatal case of a 3-month-old female infant, who died within 24 h of vaccination with hexavalent vaccine is presented. Clinical data, post-mortem findings (acute pulmonary oedema, acute pulmonary emphysema), quali-quantitative data collected from immunohistochemical staining (degranulating mast cells) and laboratory analysis with a high level of beta-tryptase in serum, 43.3 microg/l, allows us to conclude that acute respiratory failure likely due to post hexavalent immunization-related shock was the cause of death.     

Mechanisms of Lethal Cerebrovascular Accidents in Turner Syndrome

A case of intracerebral hemorrhage in Turner syndrome is reported with an analysis of possible causes of cerebrovascular accidents in this condition. A 42‐year‐old woman with known Turner syndrome died soon after hospital admission having been found unconscious at her home address. At autopsy, she showed typical features of Turner syndrome with short stature, webbing of the neck, underdeveloped breasts, and an increased carrying angle of the arm. Death was due to a large left‐sided intracerebral hemorrhage extending from the left basal ganglia into the white matter of the frontal lobe and lateral ventricle. Cases of unexpected death in Turner syndrome may arise from occult cerebrovascular accidents which may be hemorrhagic or nonhemorrhagic. Associated features include hypertension, vascular malformations, accelerated atherogenesis, cystic medial necrosis, and moyamoya syndrome. The possibility of Turner syndrome should be considered in cases where there has been a lethal cerebrovascular event in a younger woman.     

Pulmonary macrophage counts in deceased infants: baseline data for further study of infant mortality

Infant lung samples were obtained prospectively at autopsy by medical examiner pathologists in five areas of the United States and regardless of the cause of death. Four sections were examined for each case and were taken from the anterior and posterior aspects of the right and left upper lung lobes. Lung sections were stained with HAM-56 immunostain, which is specific for macrophages. Sixty-one cases were evaluated for the study. Three pathologists independently counted the number of macrophages per 40x field (10x ocular) in 10 contiguous fields near the center of each lung section examined. There was good agreement between pathologists on the average number of macrophages observed in each case. The mean macrophage count for all fields counted was 16.5 per 40x field (range 0-136), and the mean for individual cases was 16 (range 6.6-39.4). There was no observed difference between right, left, anterior, and posterior lung sections. There was a tendency for cases certified as sudden infant death syndrome to show lower macrophage counts than those with other causes of death, but the difference was of only marginal statistical significance. Seven of 10 cases in which infants died after a survival period in the hospital had a mean macrophage count greater than the overall mean of 16 per 40x field. These data suggest that mean pulmonary macrophage counts > 16 per 40x field may be a marker for causes of death other than sudden infant death syndrome or that there was a survival interval. These data may be useful as baseline data for further studies of infant mortality possibly involving pathologic changes in the lungs.     

Frequency of bronchopneumonia in children with survival interval before death

Many children do not survive after presentation in extremis. Some survive varying intervals and are found to have bronchopneumonia at death. The question is raised whether bronchopneumonia is a consequence of survival rather than the initiating disease leading to collapse. A prospective study of the deaths of 156 children divided them into two groups: 80 children with head injury and 76 with causes of death other than sudden infant death syndrome. In 43 of the total group of children, bronchopneumonia was found. In the total group, 76 survived more than a day. Of these 39 had bronchopneumonia, 32 died of head injury, and 7 had other causes of death. Of the children surviving less than a day, 4 had bronchopneumonia at death--only 1 with head injury. If bronchopneumonia is present, it is more likely to have developed after the collapse than to have caused it in this population.     

Sudden infant death syndrome in Japan

Two autopsied cases are presented, one involving a 5-month-old infant, and a 6-month-old infant both of whom died suddenly and unexpectedly. The incidence of sudden infant death syndrome in Japan is 1.2 per 1,000 babies live births. Among all cases autopsied in the departments of legal or forensic medicine in 78 universities or colleges of Japan, the incidence was 15 (0.5%) per 3,329 in 1984 and 20 (0.6%) per 3,150 in 1985.     

Oronasal blood in sudden infant death.

Oronasal secretions are observed frequently in sudden infant death syndrome (SIDS), but overt blood is uncommonly reported. The literature on oronasal blood in sudden infant death is limited. The goal of this study was to determine the frequency of oronasal blood in sudden infant deaths and to examine possible causative factors. Oronasal blood was described in 28 (7%) of 406 cases of sudden infant death. Oronasal blood could not be attributed to cardiopulmonary resuscitation in 14 cases, including 10 (3%) of 300 cases of SIDS, 2 (14%) of 14 accidental suffocation cases, and 2 (15%) of 13 undetermined cases. Eight of the 10 infants in cases of sudden infant death were bedsharing: 5 with both parents, 2 between both parents. The infant in 1 SIDS case was from a family that had had three referrals to Child Protective Services. Oronasal blood not attributable to cardiopulmonary resuscitation occurs rarely in SIDS when the infant is sleeping supine in a safe environment. Bedsharing may place infants at risk of suffocation from overlaying. Oronasal blood observed before cardiopulmonary resuscitation is given is probably of oronasal skin or mucous membrane origin and may be a sign of accidental or inflicted suffocation. Sanguineous secretions that are mucoid or frothy are likely of remote origin, such as lung alveoli. The use of an otoscope to establish the origin of oronasal blood in cases of sudden infant death is recommended.     

Increase of pulmonary density of macrophages in sudden infant death syndrome

A 1996 cytodensitometric study found increased cellular density in the pulmonary parenchyma of infants who died of sudden infant death syndrome (SIDS). The present study clarifies these results in quantifying the density of immunohistochemical subtyped inflammatory cells. Histomorphometry was used to compare the density of macrophages, granulocytes and T and B lymphocytes in the lungs of two groups of infants. From the post-mortem records of infant deaths between 1983 and 1995, 29 (mean age = 5 months) were randomly selected including 16 cases of SIDS and 13 who died of other non-pulmonary causes. Densities of immunoreactive cells were measured under blind conditions in the parenchyma. The mean density of macrophages was significantly higher in cases of SIDS compared with the controls (P = 0.0318), but there were no differences for the lymphocytes and the granulocytes. These morphometrical results must be interpreted within the methodological limits of this study, especially the non-uniform level of lung inflation between selected subjects. However, the differences in level of inflation are not sufficient to explain the observed increase of macrophage density. Indeed, the mean values of alveolar surface area, which represent an indirect measure of lung inflation, are not significantly different between the two groups. Increase of pulmonary macrophage density in SIDS agrees with three non-exclusive hypotheses: (1) an abnormal inflammatory reaction by expression of Th1 helper cell phenotype activation; (2) consequence of passive smoking; and (3) post-agonal mechanisms. Bacterial superantigens produced by toxigenic bacteria in the respiratory tract could play a role as a trigger factor that initiates a fatal cascade with overproduction of cytokines leading to death. The significant increase of pulmonary macrophage density would be the morphological expression of this potential mechanism of death.     

The Institution of a Standardized Investigation Protocol for Sudden Infant Death in the Eastern Metropole,Cape Town,South Africa,,

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.     

Pulmonary siderophages and unexpected infant death

It has been proposed that the presence of siderophages in the lungs of infants who die unexpectedly should be considered a marker of a previous hypoxic event, which may preclude a diagnosis of sudden infant death syndrome. The authors retrospectively reviewed all infant deaths (<1 year old) going to autopsy at the Denver Office of the Medical Examiner from January 1999 to January 2001. Lung sections were stained with Prussian blue, and siderophages were counted in 20 high-power fields per lobe sampled. Cell counts were performed by two independent pathologists who were blinded to history and cause of death, with good reproducibility. Iron stain results were then categorized by average number of siderophages per 20 high-power field (category 1 = <5, category 2 = 5-100, category 3A = 100-500, category 3B = >100 in a single lobe, category 4 = >500). The results were subsequently correlated to case history, autopsy findings, and cause/manner of death. Forty-three cases were reviewed. The causes of death included sudden infant death syndrome (16), asphyxia (5), undetermined (6), and other (16). Those deaths were categorized by the above criteria as follows: category 1. (32), category 2. (6), category 3. (4), and category 4. (1). All sudden infant death syndrome deaths were in category 1. Categories 1 and 2 also included deaths in which hypoxia might have been present before death because of such factors as pneumonia and congenital heart disease. Categories 3 and 4 included a known homicidal asphyxia in which repeated episodes of intentional smothering were documented, 2 probable asphyxias, 1 nonaccidental trauma, and 1 undetermined. All 5 cases had questionable circumstances surrounding the death of the infant. Pulmonary siderophages were described in only 1 of the 43 autopsy reports. It was concluded that pulmonary siderophages can be markedly increased in cases of repeated asphyxia. Siderophages may also be increased in cases where hypoxia may have been present for another reason, but not to the same degree. Siderophages are not increased in sudden infant death syndrome. Because iron-laden macrophages often are not recognized on routine examination with hematoxylin and eosin staining, iron stains may be helpful in the evaluation of infant deaths. If siderophages are present in increased amounts without an obvious explanation, further investigation is warranted.     

Diagnosis of sudden death in infants due to acute dehydration

When infants die suddenly of acute dehydration, clinical signs and autopsy findings may be equivocal or absent, and microbiologic cultures often are not helpful. Vitreous humor electrolyte and urea nitrogen concentrations were measured in 53 infants dying of gastrointestinal infections, sudden infant death syndrome (SIDS), other infectious diseases, and miscellaneous causes to determine whether these parameters would assist in the recognition and confirmation of deaths resulting from dehydration. Significant differences were found when comparing the mean sodium and urea nitrogen levels of infants dying of gastrointestinal infections with those succumbing to SIDS or other causes. We recommend that these determinations be routinely performed whenever the gross autopsy findings are insufficient to explain the death.     

The shaken baby syndrome: a serious diagnosis on an insecure foundation?

The discussion concerning the causes of infantile subdural bleedings (SDB) as well as retinal hemorrhages has become quite controversial in the last few years. The long-standing interpretation that most of these cases are the result of abuse--especially by the shaken baby syndrome (SBS)--was doubted, and the role of accidental events was emphasized. In many cases, there are no objective witnesses who observed the incident and no unambiguous traces of abuse, so that the diagnosis "shaken baby syndrome" often has to be established indirectly. A subdural bleeding (SDB) in an infant can undoubtedly be due both to an accidental and an intentional injury. Therefore, the SDB itself does not allow to draw far-reaching conclusions as to its cause. However, if an infant died or was hospitalized in a deep coma with several bridging vein ruptures and minor subdural bleeding, these findings are not compatible with an alleged minor fall. In the presence of several bridging vein ruptures, most authors are of the opinion that this is the result of a significant traumatization. In contrast to most other reports, the reliable demonstration of BV ruptures is a routine element of the postmortem diagnostic procedures at the Berlin institute of forensic medicine. In this way, a mechanical trauma can be clearly identified as the cause of the infant's death. If several bridging veins are torn, this proves a significant trauma and rules out a banal incident. The current controversial discussion on the reliability of the SBS diagnosis often makes it difficult not only for the clinician, but also for the forensic expert, to draw safe conclusions in the presence of a combination of findings long considered typical of the shaken baby syndrome. This situation is the background for presenting and discussing the major SBS findings reported in the literature and comparing them with our own expiriences. In our opinion there is still no justification for a fundamental change in the position to interpret such cases as a consequence of severe trauma caused by another person.     

Complex Congenital Heart Malformation Including Transposition of the Great Vessels,Presenting as Sudden Unexplained Infant Death

Transposition of the great vessels (TGV) is a common congenital heart defect that is difficult to diagnose before birth. Antenatal diagnosis is associated with increased survival. Unusual features such as anomalous pulmonary artery origin may delay cyanosis, decreasing clinical suspicion. A three‐week old female infant who had never been cyanotic presented for forensic autopsy due to onset of unresponsiveness at home. History included risk factors for TGV and signs of heart enlargement that were not recognized during life. Cardiac pathology consultation identified D‐type TGV with additional rare anomalies. TGV may present as sudden unexplained infant death (SUID) for forensic autopsy if variant features prevent development of cyanosis. Cardiac pathology consultation is helpful in clarifying these features.     

Apnea, glial apoptosis and neuronal plasticity in the arousal pathway of victims of SIDS

Of 27,000 infants whose sleep-wake characteristics were studied under the age of 6 months, 38 died unexpectedly 2-12 weeks after the sleep recording in a pediatric sleep laboratory. Of these infants, 26 died of sudden infant death syndrome (SIDS), and 12 of definitely identified causes. The frequency and duration of sleep apneas were analysed. Sleep recordings and brainstem histopathology were studied to elucidate the possible relationship between sleep apnea and neuropathological changes within the arousal system. Immunohistochemical analyses were conducted using tryptophan hydroxylase (TrypH), a serotonin synthesizing enzyme, and growth-associated phosphoprotein 43 (GAP43), a marker of synaptic plasticity. The terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used for apoptosis. The pathological and physiological data were correlated for each infant. In the SIDS victims, statistically significant positive correlations were seen between the number of TrypH-positive neurons in the dorsal raphe nucleus of the midbrain and the duration of central apneas (p = 0.03), between the number of TUNEL-positive glial cells in the pedunculopontine tegmental nucleus (PPTN) and the average number of spines in GAP43-positive neurons in the PPTN (p = 0.04). These findings in the dorsal raphe nucleus of the midbrain and PPTN, that play important roles in the arousal pathway suggest a possible link between changes in arousal and SIDS.     

Abnormal heart rate response during newborn sucking behavior study: Subsequent sudden infant death syndrome with cardiac conduction abnormality

This report concerns a four-month-old white female infant who exhibited abnormal feeding behavior and EKG irregularities during a newborn sucking behavior study. The immediate post-birth history showed an irregular heart rate on two occasions, but a cardiac consultation elicited no unusual findings. During sucrose sucking conditions, the heart rate increased with a beat-to-beat variation of 50 beats per minute, noted to be due to premature atrial beats. At 39 days, an EKG showed a marked sinus tachycardia of 156, a PR interval of 0.08, QRS of 0.05 and a QT of 0.26. The infant was diagnosed as a sudden infant death syndrome (SIDS) following an unexpected death at home. Subsequent cardiac pathology revealed an anomalous tract between the right atrium and the atrioventricular (AV) bundle which formed an extensive bypass of the AV node (atrio-His tract), and two accessory AV connections between the left atrium and posterior left ventricle. These findings are consistent with the Wolff-Parkinson-White syndrome type A. Only further studies can determine whether such abnormal feeding behavior with EKG irregularities can be used to identify infants who are at high risk for sudden death.