Pulmonary hemosiderin 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. Tissues were submitted regardless of the cause of death. Lung sections were stained with Prussian blue to detect deposits of hemosiderin. Fifty-nine cases were evaluated for the study. The four sections examined for each case were taken from the anterior and posterior aspects of the right and left upper lung. Three pathologists independently scanned the lung sections microscopically using a 10x objective lens (with 10x ocular lens) and indicated an "iron score" by indicating for each section if it showed no staining for iron-hemosiderin (Score 0), occasional staining with most fields negative (Score 1), focally abundant staining with most fields having no staining (Score 2), focally abundant staining with most fields showing positive staining (Score 3), or prominent staining throughout the section (Score 4). There was good agreement between pathologists on the iron score for each case. A total iron score was calculated by adding the scores based on each pathologist's observations. The mean total iron score was 6 (range, 1-44), with the range of possible total iron scores being 0 to 48. There was no significant difference between the four lung sections in a given case. Six cases had total iron scores that were at least twice the mean (i.e., total iron score > 12); in five of these cases death was caused by conditions other than sudden infant death syndrome, including one case in which asphyxia was the cause of death. These data are consistent with other reports that pulmonary hemosiderin in deceased infants is suggestive of a cause of death other than sudden infant death syndrome. The data may be useful as baseline data for further studies of infant mortality involving possible pathologic changes in the lungs.     

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.     

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.     

A comparison of respiratory symptoms and inflammation in sudden infant death syndrome and in accidental or inflicted infant death

Upper respiratory infection and pulmonary inflammation are common in sudden infant death syndrome, but their role in the cause of death remains controversial. Controlled studies comparing clinical upper respiratory infection and inflammation in sudden infant death syndrome with sudden infant deaths caused by accidents and inflicted injuries (controls) are unavailable. Our aim was to compare respiratory inflammation and upper respiratory infection within 48 hours of death and postmortem culture results in these two groups. A retrospective analysis of upper respiratory infection and pathologic variables in the trachea and lung of 155 infants dying of sudden infant death syndrome and 33 control infants was undertaken. Upper respiratory infection was present in 39% of sudden infant death syndrome cases and 40% of control cases. Upper respiratory infection was more likely to have occurred in association with more severe lymphocytic interstitial pneumonitis when sudden infant death syndrome cases and control cases were combined ( P=.04). Proximal and distal tracheal lymphocytic infiltration was more severe in control cases than in sudden infant death syndrome cases ( P=.01 and.01, respectively). Lymphocytic infiltrations of the bronchi, bronchioles, and pulmonary interstitium were similar between groups. Bronchial associated lymphoid tissue was more prominent in control cases ( P=.04). Cultures were positive in 80% of sudden infant death syndrome cases, 78% of which were polymicrobial. Among control cases, 89% were positive, with 94% being polymicrobial. This study confirms that microscopic inflammatory infiltrates in sudden infant death syndrome are not lethal.     

Postmortem cerebrospinal fluid pleocytosis

We show that postmortem cerebrospinal fluid (CSF) pleocytosis is a common event. Postmortem cerebrospinal or ventricular fluid was obtained from children and adults. The cells were counted and morphologically characterized using several histochemical markers. Infants exhibit a brisk postmortem CSF pleocytosis. Sudden infant death cases have relatively high CSF counts. Typeable cells are mononuclear and consist of approximately 60%-70% lymphocytes and 20%-40% macrophages. When postmortem duration is greater than 12 h, the cells become vacuolated and cannot be identified. The etiology of these findings requires further study.     

Quantitative analysis of pulmonary neuroendocrine cell distribution of the fetal small airways using double-labeled immunohistochemistry

Pulmonary neuroendocrine cells (PNECs) are supposed to play an essential role in development of fetal lung and neonatal respiratory adaptation. Some previous studies have suggested the close relation between PNECs and sudden infant death syndrome (SIDS). To investigate how PNECs distribute to the thermal bronchioli of fetal lung may be a clue to clarify this relation. Since it is difficult to distinguish bronchiole from alveolus in fetal lung, we performed double immunostaining with antibody against chromogranin A (CGA) and alpha-smooth muscle actin (SMA) which can make clear distinction between them. In this study, formalin-fixed, paraffin-embedded lung tissues from 18 autopsy cases from 16 to 28 weeks of gestation were assessed. CGA immunopositive cells were counted and the length of basement membranes of terminal bronchioli was measured with computed image analyzer. Density of PNECs was expressed as the number of immunopositive cells per millimeter of basement membrane. Terminal bronchiole stained with SMA was clearly distinguished from alveolus at 16 weeks. With gestational age, CGA immunopositive PNECs were gradually increased in 2 folds by the 25th week. After that, their density wasn't changed significantly until termination. It is suggested that PNECs in terminal bronchiole was playing an important role in morphogenesis of alveolar ducts and alveolar sacks.     

Screening of milk aspiration in 105 infant death cases by immunostaining with anti-human alpha-lactalbumin antibody.

To determine the frequency and degree of milk aspiration in infant death cases, immunohistochemical examinations were performed on lung sections from 41 sudden death cases and 64 in-hospital death cases using anti-human alpha-lactalbumin antibody. Milk aspiration to some degree was detected in more than half of the sudden death cases and in about one-third of the in-hospital death cases. A semi-quantitative examination of the amount of aspirated milk was subsequently performed in the positive cases. The amount of aspirated milk in the sudden death cases was significantly higher than that in the in-hospital death cases. The frequency distribution of the amount of aspirated milk was similar in shape in both groups. In most cases, a very small amount of aspirated milk was detected. The aspirated milk was assumed to be a result of occasional gastroesophageal reflux or cardiopulmonary resuscitation. However, in five cases, much larger amounts of aspirated milk were found. In these cases, milk aspiration may have been an important part of the cause of death. We concluded that slight milk aspiration is not rare in infant death cases, and that in a few cases, the aspiration is lethal. An immunohistochemical screening test is available to perform a postmortem diagnosis in these cases.     

A Retrospective Study of the Investigation of Homicidal Childhood Asphyxial Deaths

As one of the leading causes of traumatic deaths in newborns, infants, and young children, there is no anatomic or microscopic feature that is pathognomonic for asphyxial deaths. Instead, pathologists rely on investigation information, including confessions and/or witness statements, and potential evidence at the scene. Twenty cases of homicidal newborn, infant, and young children asphyxial deaths were reviewed, which included death and police investigation reports and autopsy reports, as well as histology slides of lung sections. This series of homicidal asphyxial deaths highlight that, in a vast majority of such cases, the final cause and manner of death rulings are dependent on confession by the perpetrator. Furthermore, this series highlights the possible role of histology to help forensic pathologists better certify asphyxial deaths. Finally, this series emphasizes important investigation points and considerations at autopsy during the investigation of asphyxial deaths in newborns, infants, and young children.     

A Case of Sudden Infant Death Due to Incomplete Kawasaki Disease

Although Kawasaki disease (KD) is a self‐limiting disease, it may cause sudden cardiac death. Diagnosis of KD is principally based on clinical signs; however, some infant cases do not meet the criteria. Such cases are identified as incomplete KD. The sudden death risk in incomplete KD cases is similar to conventional KD. In our 5‐month‐old case, he had been admitted to a hospital for a fever and suppuration at the site of Bacille de Calmette et Guerin (BCG) vaccination. However, after discharge from the hospital, his C‐reactive protein (CRP) levels declined, he got indisposed and died suddenly. A medico‐legal autopsy revealed myocarditis, coronaritis, platelet‐aggregated emboli in coronary arteries, and myocardial degeneration, suggesting that the fatal myocardial infarction was due to thrombus emboli in the coronary arteries. Forensic pathologists therefore should pay attention to the cardiac pathology originated from incomplete KD as a potential cause in cases of sudden infant death.     

Diagnostic dilemma of sudden deaths due to acute hemorrhagic pancreatitis

Sudden death due to acute pancreatitis has been rarely determined. A review of 3305 autopsies performed between 1991 and 2001 at the Council of Forensic Medicine found 12 cases (0.36%) with sudden death due to acute hemorrhagic pancreatitis without symptoms. A history of chronic alcohol ingestion was obtained from family in four cases (33%), and no stones were found in the bile ducts or in the gall bladders. During the autopsies, hemorrhage and edema were localized on the head of the pancreas in three cases and the whole pancreas in nine cases. The most common extrapancreatic pathology was found in the lung including pulmonary edema, alveolar hemorrhage, pleural effusion, and pulmonary congestion. There was no correlation between pulmonary and pancreatic damage. It is suggested that the forensic pathologists who are dealing with sudden unexpected death must not ignore the examination of pancreatic and extrapancreatic regions to avoid missing acute pancreatitis.     

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.     

Right ventricular damage due to pulmonary embolism: examination of the number of infiltrating macrophages

To investigate the pathological changes in the heart induced by pulmonary embolism, 20 autopsy cases of pulmonary embolism and 10 control cases of acute death from traumatic injury were examined. Adding to the routine hematoxylin-eosin (HE) staining, immunostaining with CD68 pan-macrophage marker was performed on the specimens obtained from both right and left ventricular walls. The number of macrophages was counted semi-quantitatively in 100 random high-power fields (HPF). Although typical pathological findings of myocardial infarction was not observed in any of the cases, 16 of the 20 pulmonary embolism cases showed an increase in the number of macrophages, mainly in the right ventricular wall. Four cases showed massive macrophage infiltration in the entire right ventricular wall. It is speculated that ischemia due to pulmonary embolism may be connected to its pathogenesis.     

Unexpected perinatal death and sudden infant death syndrome (SIDS): anatomopathologic and legal aspects

This work intends to be a review of the recent histopathological findings elicited by research into sudden and unexpected perinatal death and sudden infant death syndrome (SIDS) that have dictated a novel approach to the inherent problems by pathologists, especially those entrusted with forensic medical authority. The new approach stems from the recent advances made in the understanding of neuro- and/or cardiac-conduction-system diseases present in unexpected perinatal death and SIDS. These demand that an accurate morphologic examination be performed of these structures, which modulate respiratory, cardiovascular, digestive, and arousal activities, in all victims of sudden death. A histopathologic study of an ample register of cases of victims of sudden death, either perinatally or in early infancy, has demonstrated frequent alterations both of the autonomic nervous system (especially hypoplasia of the arcuate nucleus) and of the cardiac conduction system (accessory atrioventricular pathways). The present research provides an in-depth study of the many still-controversial aspects underlying perinatal unexpected death and SIDS and is recommended for professionals working in the forensic field, whose greater insight into this problem will allow more complete medicolegal documentation.     

Laryngeal basement membrane thickening is not a reliable postmortem marker for SIDS: results from the Chicago Infant Mortality Study.

It has been suggested that laryngeal basement membrane (LBM) thickening is a pathognomonic postmortem marker for sudden infant death syndrome (SIDS) and is not seen in other causes of explained sudden infant death. To test this hypothesis, we evaluated longitudinal sections of the right hemilarynx taken through the midpoint of the true vocal cord from 129 SIDS cases and 77 postneonatal sudden infant death controls. Using a five-point semi-quantitative scale, maximum LBM thickness (LBMT) for SIDS cases and controls was not statistically different (mean, 2.39 + 0.69 and 2.40 + 0.77, respectively). Likewise, scores based on the average thickness along the entire basement membrane (i.e., "average" score), were not found to be different between SIDS cases and controls. Average and maximum LBMT increased with age in both SIDS cases and controls and were not different between SIDS cases and controls within each age interval. Similar trends in the distribution of maximum and average LBMTs were found between black and Hispanic SIDS and controls; the number of white/non-Hispanic infants was too low for meaningful comparisons. Maximum and average LBMTs were not different in SIDS cases and controls exposed to environmental tobacco compared with unexposed infants. The LBMTs also increased significantly with body weight and length in both SIDS cases and controls. Finally, there were no differences in LBMT in infants intubated prior to death compared with those who were not intubated. From these data, we conclude that LBMT is not pathognomonic of SIDS, is present or absent with equal frequency in SIDS and controls, increases with postnatal age, and does not correlate with passive smoke exposure. Therefore, LBMT should not be used to diagnose SIDS.     

Diaphragmatic muscle fibre necrosis in SIDS

Observations of acute muscle fibre necrosis, as seen in 242 sudden infant death syndrome (SIDS) cases is described. The lesion is a focal acute anoxic muscle fibre coagulative necrosis in some cases followed by myocytolysis, central vacuolation, macrophage and phagocytic cell infiltrate, stromal condensation and scarring.     

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.     

低钾型周期性麻痹猝死16例法医学分析

目的 探讨低钾型周期性麻痹猝死案例的法医学鉴定要点.方法 对中山大学法医鉴定中心2004～2010年间受理的16例低钾型周期性麻痹猝死案例进行回顾性分析.结果 16例案例中以20～39岁男性多见,平均年龄(35.12±8.54)岁;血清钾平均水平(2.29±0.60) mmol/L.结论 低钾型周期性麻痹猝死案例缺乏特异性组织病理学改变,法医学检案中应结合临床实验室检测结果综合评定.     

Sudden death as the initial manifestation of primary pulmonary hypertension. Report of four cases

Four autopsy cases are presented in which sudden death was the initial manifestation of primary pulmonary hypertension. The arteriopathy was plexogenic in two cases (a 3-year-old girl and a 16-year-old boy) and was thrombotic in two other cases (55- and 59-year-old women). The diagnosis of primary pulmonary hypertension, particularly in forensic cases, requires that the pathologist be especially aware of the possibility and that a careful evaluation of multiple sections of lung be performed. Determination of the histopathologic type also is important because some forms of the disease may be familial and may be treatable in other family members if they are detected early.     

Could Intra‐alveolar Hemosiderin Deposition in Adults be Used as a Marker for Previous Asphyxial Episodes in Cases of Autoerotic Death?

Intra-alveolar hemorrhage and hemosiderin have been cited as possible markers of recent and remote asphyxial events. Little study has been undertaken of the potential significance of intra-alveolar hemosiderin in adults as a potential marker of previous sublethal asphyxial episodes. Ten cases of lethal sexual asphyxia (an entity known to be associated with repetitive sublethal asphyxial episodes) and 20 randomly selected, age- and sex-matched controls had sections of lung stained for hemosiderin. Subsequently, intra-alveolar, iron-containing macrophages were counted. All cases were men (ages 15-50 years; mean 31.8). No significant increase in hemosiderin was found in victims of sexual asphyxia, indicating that asphyxial episodes in sublethal sexual asphyxial activities may not be sufficiently intense or prolonged to cause intra-alveolar hemorrhage or that intra-alveolar hemorrhage in adults is a relatively nonspecific finding. These results do not support intra-alveolar hemosiderin deposition as a marker for previous sublethal asphyxial events in autoerotic asphyxia.