Pathological changes of the heart in sudden infant death

Cardiac ion channels associated with unexplained stillbirth - an immunohistochemical study

OBJECTIVES

Despite the use of post-mortem investigations, approximately 20% of stillbirths remain unexplained. Cardiac ion channelopathies have been identified as a cause of death in Sudden Infant Death Syndrome (SIDS) and could be associated with unexplained stillbirths. This study aimed to understand if the expression or localisation of cardiac ion channels associated with channelopathies were altered in cases of unexplained stillbirths.

METHODS

A case control study was conducted using formalin-fixed cardiac tissue from 20 cases of unexplained stillbirth and a control group of 20 cases of stillbirths from intrapartum hypoxia. 4 µm tissue sections were stained using haematoxylin and eosin, Masson's trichrome (MT) and Elastic van Gieson (EVG). Immunohistochemistry (IHC) was performed using antibodies against CACNA1G, KCNJ2, KCNQ1, KCNH2 and KCNE1. The cardiac conduction system in samples stained with MT and EVG could not be identified. Therefore, the levels of immunoperoxidase staining were quantified using QuPath software.

RESULTS

The nuclear-cytoplasmic ratio of sections stained with haematoxylin and eosin was higher for the hypoxia group (hypoxia median 0.13 vs. 0.04 unexplained, p < 0.001). CACNA1G (unexplained median 0.26 vs. hypoxia 0.30, p=0.009) and KCNJ2 (unexplained median 0.35 vs. hypoxia 0.41, p=0.001) had lower staining intensity in the unexplained stillbirth group. There were no statistically significant differences in the staining intensity of KCNQ1, KCNH2 and KCNE1.

CONCLUSIONS

Two ion channels associated with channelopathies demonstrated lower levels of expression in cases of unexplained stillbirth. Further genetic studies using human tissue should be performed to understand the association between channelopathies and otherwise unexplained stillbirths.

Seizure-related deaths in children: The expanding spectrum

Although seizures are common in children, they are often overlooked as a potential cause of death. Febrile and nonfebrile seizures can be fatal in children with or without an epilepsy diagnosis and may go unrecognized by parents or physicians. Sudden unexpected infant deaths, sudden unexplained death in childhood, and sudden unexpected death in epilepsy share clinical, neuropathological, and genetic features, including male predominance, unwitnessed deaths, death during sleep, discovery in the prone position, hippocampal abnormalities, and variants in genes regulating cardiac and neuronal excitability. Additionally, epidemiological studies reveal that miscarriages are more common among individuals with a personal or family history of epilepsy, suggesting that some fetal losses may result from epileptic factors. The spectrum of seizure-related deaths in pediatrics is wide and underappreciated; accurately estimating this mortality and understanding its mechanism in children is critical to developing effective education and interventions to prevent these tragedies.

Histologic spectrum of the cardiac conducting tissue in non-natural deaths under 30 years of age: an analysis of 43 cases with special implications for sudden cardiac death

In the past, histological findings of the cardiac conduction system or its adjacent structures, such as filiform fibers at the transition from bundle of His to bundle branches, connective tissue at the apex of the ventricular septum, or fibromuscular alterations of the arteries has been considered as a cause of death. However, the prevalence of such findings in a healthy population has been rarely analyzed systematically. In the present study, the morphology of the cardiac conduction system of 43 heart-healthy individuals who died of non-natural causes (ages 0 to 30 years) was investigated. In a high percentage of cases, connective tissue at the apex of the ventricular septum (97.7%), filiform fibers at the transition from bundle of His to the bundle branches (27.9%), and fibromuscular proliferations of the sinoatrial node artery (41.9%), and the AV-node artery (39.5%) could be detected. Based on our observations, these alterations should not be considered as a pathologic entity or as a cause of death.

Acute aortic dissection with carotid and coronary malperfusion: from imaging to pathology

Postmortem imaging, including postmortem computed tomography angiography, has become an integral tool in forensic investigation in recent years. A relatively new technique, multiphase postmortem computed tomography angiography, allows detailed visualization of the vascular system and makes it possible to evaluate the dynamic perfusion of aortic branches, including the coronary arteries. Here, we report a case of aortic dissection involving the ascending aorta (type A) with coronary and carotid malperfusion. This case illustrates the complementary use of many of the diagnostic tools that are now available in forensic practice, from imaging to conventional autopsy to pathologic techniques such as immunohistochemistry.

Evaluation of forensic perinatal and neonatal autopsies in Istanbul

OBJECTIVE

Autopsy findings play an important role in prevention of perinatal and neonatal deaths. Therefore, we attempted to reveal demographic and forensic features of these deaths in Turkey.

METHODS

We retrospectively reviewed autopsy reports for 184 cases of perinatal deaths released from Istanbul Forensic Medicine Institute Morgue between 2000 and 2002 and investigated demographic and medico-legal features of the cases.

RESULTS

The mean age of the cases was 2.98 +/- 6.41 days. Fifteen point two percent (15.2%) of the cases were of murder, 52.7% of the cases were illegitimate children and 41.3% had the ability to survive.

CONCLUSION

It can be suggested that autopsy and post-mortem examinations should be performed in order to determine the real causes and contributing factors of perinatal and neonatal deaths. Data obtained in autopsies and postmortem examinations will make great contributions to the prevention of these deaths.

Sudden infant death syndrome (SIDS)--standardised investigations and classification: recommendations

Sudden infant death syndrome (SIDS) still accounts for considerable numbers of unexpected infant deaths in many countries. While numerous theories have been advanced to explain these events, it is increasingly clear that this group of infant deaths results from the complex interaction of a variety of heritable and idiosyncratic endogenous factors interacting with exogenous factors. This has been elegantly summarised in the "three hit" or "triple risk" model. Contradictions and lack of consistencies in the literature have arisen from diverse autopsy approaches, variable applications of diagnostic criteria and inconsistent use of definitions. An approach to sudden infant death is outlined with discussion of appropriate tissue sampling, ancillary investigations and the use of controls in research projects. Standardisation of infant death investigations with the application of uniform definitions and protocols will ensure optimal investigation of individual cases and enable international comparisons of trends.

Sudden infant death syndrome and long QT syndrome: an epidemiological and genetic study

Sudden infant death syndrome (SIDS) is a frequent cause of death among infants. The etiology of SIDS is unknown and several theories, including fatal ventricular arrhythmias, have been suggested. We performed an epidemiological and genetic investigation of SIDS victims to estimate the presence of inherited long QT syndrome (LQTS) as a contributor for SIDS. Forty-one consecutively collected and unrelated SIDS cases were characterized by clinical and epidemiological criteria. We performed a comprehensive gene mutation screening with single-strand conformation polymorphism analysis and sequencing techniques of the most relevant LQTS genes to assess mutation frequencies. In vitro characterization of identified mutants was subsequently performed by heterologous expression experiments in Chinese hamster ovary cells and in Xenopus laevis oocytes. A positive family history for LQTS was suspected by mild prolonged Q-T interval in family members in 2 of the 41 SIDS cases (5%). In neither case, a family history of sudden cardiac death was present nor a mutation could be identified after thorough investigation. In another SIDS case, a heterozygous missense mutation (H105L) was identified in the N-terminal region of the KCNQ1 (LQTS 1) gene. Despite absence of this mutation in the general population and a high conservational degree of the residue H105 during evolution, electrophysiological investigations failed to show a significant difference between wild-type and KCNQ1(H105L)/minK-mediated I(Ks) currents. Our data suggest that a molecular diagnosis of SIDS related to LQTS genes is rare and that, even when an ion channel mutation is identified, this should be regarded with caution unless a pathophysiological relationship between SIDS and the electrophysiological characterization of the mutated ion channel has been demonstrated.

Sudden cardiac death in a child affected by Prader-Willi syndrome

A case of sudden cardiac death in a 3-year-old young male affected by Prader-Willi syndrome, clinically diagnosed and confirmed by means of DNA methylation, is presented. The infant suddenly collapsed at home and was taken apparently unconsciousness by his mother to the emergency clinic where he was pronounced dead. A complete postmortem examination was performed and the histological findings led to the definition of cardiac death with a typical picture of contraction band necrosis. Pulmonary hypoxic alterations are frequently reported as the primary cause of death in PWS cases. In this fatal case according to the macroscopic and microscopic findings, the cause of death was most likely cardiac and possibly related to contraction band necrosis linked with ventricular fibrillation and sudden death.

Epstein–Barr virus myocarditis as a cause of sudden death: two autopsy cases

Although the Epstein-Barr virus (EBV) causes acute infection accompanied by a high fever in young people, there appears to be few reports of a fatal outcome involving myocarditis. We report two cases of unexpected sudden death due to acute myocarditis possibly caused by the EBV. They each visited a hospital due to common cold-like symptoms and unexpectedly died several days later. In both cases, autopsy revealed myocardial necrosis with marked lymphocytic infiltration. Polymerase chain reaction (PCR) screening was positive for the EBV, whereas immunohistochemistry and in situ hybridization for the EBV were negative. Serological investigations showed a mild elevation in antiviral capsid antigen IgG and anti-EBV nuclear antigen IgG in both cases. Immunohistochemical study of lymphocytic infiltrates showed strong positivity for a T-cell marker (CD45R0) in the myocardium and pharyngeal mucosa. These cases suggest the potential risk of mortality from acute EBV infection in young people, even without severe clinical manifestations, and the importance of microbiological investigations, including PCR procedures, in postmortem diagnosis of infectious diseases.

Black oesophagus: a rare disorder with potentially fatal outcome. A forensic pathological approach based on five autopsy cases

Black oesophagus is a rare pathological condition of unknown aetiology characterised by a full length, circumferential black discolouration of the entire oesophageal mucosa. The disease is sporadically encountered during upper gastrointestinal endoscopy. We used conventional histology, enzyme histochemistry and immunohistology to examine five autopsy cases (four males, one female; age range 43-86 years) of black oesophagus. On microscopical examination, the esophageal mucosa was entirely necrotic with demarcation by a leukocytic infiltrate in the upper submucosa. This infiltrate was dominated by neutrophilic granulocytes and scattered macrophages lacking haemosiderin deposits, placing the noxious mucosal injury in a time frame of approximately 24-72 h prior to death. Black oesophagus was established as the immediate cause of death in one case due to desanguination from the oesophagus and significantly contributed to the fatal outcome in a second case. Apart from a history of chronic alcohol consumption in four cases, no other pre-existing pathological or debilitating conditions could be established. The remarkably consistent pathomorphological picture of the disease seems to be the result of impaired microcirculation of the oesophageal mucosa due to prolonged hypotension of variable aetiology. The diagnosis of black oesophagus requires exclusion of other causes such as ingestion of caustic materials and should be based on histological examination.

Suffocation and poisoning?the hard-hitting side of Munchausen syndrome by proxy

Munchausen syndrome by proxy (MSBP) is a severe and difficult to diagnose form of child abuse characterised by the simulation, aggravation or production of symptoms of illness in a child by an adult. MSBP often leads to multiple hospitalisations and has a high mortality and long-term morbidity. This study describes the cases of 5 families with 8 children affected who presented with unexplained neurological or gastrointestinal symptoms or even loss of consciousness. All were victims of poisoning or suffocation by their mothers. Two of those children died and were initially diagnosed as SIDS or natural death, respectively. They were only recognised as MSBP victims after another sibling had fallen ill with similar symptoms. The cases are discussed in consideration of the relevant literature. In addition warning signs of this forensically relevant syndrome and a strategy for the management of suspected MSBP cases are described.

Sudden cardiac death due to hypersensitivity myocarditis during clozapine treatment

The case concerns the sudden death of a 29-year-old male during clozapine therapy started 2 weeks before. He had a history of treatment-resistant chronic schizophrenia. A complete immunohistochemical study was performed on heart specimens. Histologically, the heart presented diffuse eosinophilic infiltrates located around perivascular structures and focal myocyte necrosis with numerous interstitial eosinophils admixed with histiocytes. The diagnosis of acute myocarditis with an eosinophilic infiltrate was established as the cause of death. The autopsy findings and a detailed medical history supported the conclusion that clozapine-induced hypersensitivity myocarditis was the most likely cause of death.

Fatal hepatic haemorrhage in a child-peliosis hepatis versus maltreatment

A 2.5-year-old boy with known myotubular myopathy (Spiro-Shy-Gonatas syndrome) and gonadorelin intake 9 months ante-mortem was found dead in his bed at home. At autopsy a ruptured subcapsular haematoma of the liver with resulting haemoperitoneum (600 ml) was found. Both lobes of the liver showed numerous circular blood foci <1 mm-2 cm in diameter. Signs of mechanical trauma such as bruising of the abdominal wall were absent. Histologically, the blood cysts were commonly connected to the sinusoids but did not have an endothelial lining and the reticular fibres showed ruptures. These pathomorphological findings are characteristic for peliosis hepatis and the cause of death was therefore determined to be exsanguination due to hepatic haemorrhage from peliosis hepatis instead of from mechanical trauma. To our knowledge this is the youngest casualty from peliosis reported so far.

Three subsequent infanticides covered up as SIDS

Within a period of 9 years a young woman lost 3 daughters during infancy and each time death was attributed to the sudden infant death syndrome. The children had different fathers and died at the ages of 11 weeks, 7 weeks and 2 weeks, respectively. A fourth daughter survived and lives separated from the mother together with her father and is healthy. At autopsy the last of the three deceased infants did not reveal any pre-existing pathological organ findings, except for acute pulmonary emphysema and extensive intra-alveolar bleeding. As a consequence the strong suspicion of mechanical suffocation arose. Subsequent police investigations produced incriminating clues that the first two children had also been suffocated. On confrontation with the autopsy findings and investigation results, the woman confessed that she herself had killed the first two infants by pressing a cushion on their faces. In the case of the third death the baby had been smothered by the child's father who in agreement with the mother put a plastic film on mouth and nostrils.

Sudden death due to a haemoglobin variant

A previous healthy 35-year-old man was found dead in his truck. Shortly before death he merely complained of influenza-like symptoms. The histological examination revealed evidence of a massive accumulation of sickle cells in smaller blood vessels. After molecular genetic analysis, the preliminary diagnosis of "sickle cell disease" was finally changed to the diagnosis of a sickle cell trait. It is presumed that an epileptic attack which also has to be considered as a concurring cause of death, precipitated sickling of the erythrocytes and led to a fatal sickle cell crisis.