Death Due to Anaphylactic Reaction: The Role of the Forensic Pathologist in an Accurate Postmortem Diagnosis

Evaluation of Apoptotic Caspase-3 Immunopositivity in Human Model of Asphyxial Death

The pathological mechanisms underlying the ligature mark in hanging involve the skin layers and an ischemic mechanism. The apoptotic process develops whenever ischemic mechanisms affect the dermal and epidermal layers. Effector caspase-3 appears to play a crucial role in both acute and chronic pressure-induced skin ischemia. The aim of this study is to identify the role of caspase-3 as a marker of supravitality in the diagnosis of premortem hanging. Skin samples from ligature marks in hanging cases were collected to investigate this apoptotic process. The caspase-3 levels in compressed skin were significantly higher compared to those found in healthy skin (p < 0.005). The apoptotic process in ischemic epidermal cells begins with stable mechanical stress, as seen in the hanging model. Caspase-3 expression seems to vary from minutes after the initial stress input. Caspase-3 activation is an ATP-dependent process and can only occur if the victim was alive before the pressure was applied. Caspase-3 is a reliable marker of supravitality in ligature marks in premortem hanging cases.

Utility of biomarkers in the postmortem diagnosis of fatal Anaphylaxis: A scoping review

BACKGROUND

Diagnosing anaphylactic deaths is a challenging task for forensic pathologists. Although serum tryptase is considered to be a reliable biomarker, there are limitations to it. Thus, there is an urgent need to explore various other potential biomarkers which could be of diagnostic value, along with Tryptase, to diagnose anaphylactic shock at autopsy.

AIM

We want to systematically review the accuracy of newer postmortem biomarkers for anaphylaxis, such as chymase or eosinophilic cationic protein. Before embarking on this project, we intend to assess the feasibility of conducting systematic reviews on this topic. and identify any deficiencies in the existing literature to guide research priorities.

METHODOLOGY

We followed PRISMA guidelines and conducted the search in four databases, namely Medline, Scopus, EBSCO-CINAHL, and TRIP. Rayyan AI software was used to screen the articles.

RESULTS

A total of 6112 articles were retrieved from the search, and 5079 articles were screened after removing duplicates. Only 25 articles were finally available as per our inclusion criteria. Studies pertaining to post-mortem tryptase levels were found in large numbers, with two recently done systematic reviews on this topic. The number of studies available on other newer biomarkers was too few. More clinical studies are needed before a meta-analysis can be done. Hence, we could perform only a narrative review on the topic.

DISCUSSION

There is a scarcity of literature with definite cutoff levels for markers other than Tryptase. Based on the available studies, it is not possible to do diagnostic accuracy reviews at the moment. Hence, we narrate the usefulness of biomarkers like Immunoglobulin E, Chymase, Carboxypeptidase A3, Diamine Oxidase, Histamine and Eosinophilic Cationic Protein.

CONCLUSION

Based on the available evidence, serum tryptase is recognized as the primary biomarker for the postmortem diagnosis of anaphylactic death, with elevated levels strongly indicating anaphylaxis. Additionally, serum IgE, particularly allergen-specific IgE, is a valuable complementary biomarker. Further research is needed to understand the performance of other biomarkers.

Serum metabolomics analysis reveals potential biomarkers of penicillins-induced fatal anaphylactic shock in rats

Immunoglobulin E (IgE)-mediated immediate hypersensitivity reactions are the most concerning adverse events after penicillin antibiotics (PENs) administration because of their rapid progression and potential for fatal outcome. However, the diagnosis of allergic death is a forensic challenge because it mainly depends on nonspecific characteristic morphological changes, as well as exclusion and circumstantial evidence. In this study, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) was used to screen potential forensic biomarkers of fatal anaphylactic shock induced by four PENs (benzylpenicillin (BP), amoxicillin (AMX), oxacillin (OXA), and mezlocillin (MEZ)), and analyzed the metabolites, metabolic pathway and the mechanism which were closely related to the allergic reactions. The metabolomics results discovered that a total of 24 different metabolites in all four anaphylactic death (AD) groups, seven of which were common metabolites. A biomarker model consisting of six common metabolites (linoleic acid, prostaglandin D2, lysophosphatidylcholine (18:0), N-acetylhistamine, citric acid and indolelactic acid) AUC value of Receiver Operating Characteristic (ROC) curve was 0.978. Metabolism pathway analysis revealed that the pathogenesis of PENs-induced AD is closely related to linoleic acid metabolism. Our results revealed that the metabolomic profiling has potential in PENs-induced AD post-mortem diagnosis and metabolic mechanism investigations.

Sudden Death: A Practical Autopsy Approach to Unexplained Mediastinitis Due to Fatal Untreated Neck Infections-A Systematic Review

Neck infections are often prone to being underestimated and can manifest insidiously. The spread of infection can lead to translocation into thoracic areas, causing descending necrotizing mediastinitis (DNM). However, the application of the post-mortem approach in such cases is not well-described in the literature. A literature review was carried out according to the PRISMA methods. Nine papers were included in the final review, revealing different levels of involvement of neck layers that can be linked to different causes. Expertise with respect to the anatomy of the fasciae and spaces of the neck enables an understanding of the pathogenesis of DNM. However, a clear autoptic description was not provided in any of the articles. Therefore, we also employed a practical post-mortem approach to cases of death due to DNM. It is fundamental for pathologists to identify the exact head and neck structures involved. Providing dissectors with support from an otolaryngologist could be useful. This paper could help address such difficult cases.

Fatal Outcome Due to Kounis Syndrome Following Fluorescein Retinal Angiography: A Case Report

Kounis Syndrome (KS) is a clinical entity triggered by allergic or hypersensitivity reactions capable of inducing acute coronary events. Several causes can induce KS, including drugs and insect stings. Here, a rare case of post mortem assessment of fatal KS related to fluorescein retinal angiography has been reported. An 80-year-old man in follow-up for a retinal vein thrombosis underwent a retinal fluoroangiography. Approximately 30 min later, the patient complained of sweating and dizziness, and suddenly lost consciousness due to a cardiac arrest. Despite the immediate cardiopulmonary resuscitation, he died. The autopsy revealed foamy yellowish edema in the respiratory tract and coronary atherosclerosis with eccentric plaques partially obstructing the lumen. The routine histology highlighted lung emphysema and myocyte break-up with foci of contraction band necrosis at the myocardial tissue. Biochemistry showed increased serum tryptase, troponin, and p-BNP. Activated and degranulated (tryptase) mast cells were detected, using immunohistochemistry, in the larynx, lungs, spleen, and heart. Acute myocardial ischemia due to allergic coronary vasospasm related to fluorescein hypersensitivity has been assessed as cause of death. KS-related deaths are considered rare events, and the post mortem assessment of KS quite difficult. The integration of several investigations (gross and microscopic examination, biochemistry, immunohistochemistry) can provide useful findings to support the diagnosis, helping to reduce the unrecognized cases as much as possible.

Sudden Cardiac Death, Post-Mortem Investigation: A Proposing Panel of First Line and Second Line Genetic Tests

Investigating the causes of Sudden cardiac death (SCD) is always difficult; in fact, genetic cardiac conditions associated with SCD could be "silent" even during autopsy investigation. In these cases, it is important to exclude other aetiology and assist to ask for genetic investigations. Herein, the purpose of this review is to collect the most-implicated genes in SCD and generate a panel with indications for first line and second line investigations. A systematic review of genetic disorders that may cause SCD in the general population was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We subsequently listed the genes that may be tested in the case of sudden cardiac death when the autopsy results are negative or with no evidence of acquired cardiac conditions. To make genetic tests more specific and efficient, it is useful and demanded to corroborate autopsy findings with the molecular investigation as evident in the panel proposed. The genes for first line investigations are HCM, MYBPC3, MYH7, TNNT2, TNNI3, while in case of DCM, the most implicated genes are LMNA and TTN, and in second line for these CDM, ACTN2, TPM1, C1QPB could be investigated. In cases of ACM/ARVC, the molecular investigation includes DSP, DSG2, DSC2, RYR2, PKP2. The channelopathies are associated with the following genes: SCN5A, KCNQ1, KCNH2, KCNE1, RYR2. Our work underlines the importance of genetic tests in forensic medicine and clinical pathology; moreover, it could be helpful not only to assist the pathologists to reach a diagnosis, but also to prevent other cases of SCD in the family of the descendant and to standardise the type of analysis performed in similar cases worldwide.

An Insight into Kounis Syndrome: Bridging Clinical Knowledge with Forensic Perspectives

Kounis syndrome (KS) is an acute coronary syndrome triggered by allergic or hypersensitivity reactions. Incidence rates vary, with studies reporting 19.4 per 100.000 among all admissions and 3.4% among allergy patients. This review explores the expanding understanding of KS, encompassing various manifestations, and focusing on both clinical data and forensic findings useful in performing a diagnosis. The pathophysiology of this syndrome involves a complex interplay between allergic reactions and the cardiovascular system. Mast cell activation, histamine release, leukotrienes, cytokines, and platelet activation can contribute to coronary events. Three types of classification systems (allergic angina, allergic myocardial infarction, allergic stent thrombosis) aid in categorizing presentations. The diagnosis of KS relies on clinical presentation, laboratory findings, and imaging. Postmortem assessment of KS is based on the integration of circumstantial data, autopsy, and histological findings. Biochemical and immunohistochemical analyses also contribute to postmortem diagnosis. In conclusion, a combined, multidisciplinary approach should be used to ease the diagnostic process, which is crucial for forensic practitioners in confirming KS occurrence.