The effects of different sampling techniques on peripheral post mortem tryptase levels: a recommended sampling method

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.

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.

Postmortem Biochemistry and Immunohistochemistry in Anaphylactic Death Due to Hymenoptera Sting: A Forensic Case Report

BACKGROUND

Postmortem assessment of anaphylactic death is a challenge for forensic pathologists. One of the most frequent elicitors of anaphylaxis is insect venom. Here, a case of anaphylactic death due to Hymenoptera stings is reported to highlight the contribution of postmortem biochemistry and immunohistochemistry in assessing the cause of death.

CASE REPORT

A 59-year-old Caucasian man working on his farm was presumably stung by a bee and died. He had a history of previous sensitization to insect venom. The autopsy revealed no signs of insect puncture, mild edema of the larynx, and foamy edema in the bronchial tree and lungs. Routine histology showed endo-alveolar edema and hemorrhage, bronchospasm, and scattered bronchial obstruction due to mucus hyperproduction. Biochemical analysis was performed, and serum tryptase was equal to 189 µg/L, total IgE was 200 kU/L, and specific IgE dosage was positive for bee and yellow jacket species. Immunohistochemistry for tryptase detection was carried out, revealing mast cells and degranulated tryptase expression in the larynx, lungs, spleen, and heart. These findings led to the diagnosis of anaphylactic death due to Hymenoptera stings.

CONCLUSIONS

The case highlights that the role of biochemistry and immunohistochemistry in the postmortem assessment of anaphylactic reactions should be stressed by forensic practitioners.

Postmortem investigation of fatalities following vaccination with COVID-19 vaccines

Thorough postmortem investigations of fatalities following vaccination with coronavirus disease 2019 (COVID-19) vaccines are of great social significance. From 11.03.2021 to 09.06.2021, postmortem investigations of 18 deceased persons who recently received a vaccination against COVID-19 were performed. Vaxzevria was vaccinated in nine, Comirnaty in five, Spikevax in three, and Janssen in one person. In all cases, full autopsies, histopathological examinations, and virological analyses for the severe acute respiratory syndrome coronavirus 2 were carried out. Depending on the case, additional laboratory tests (anaphylaxis diagnostics, VITT [vaccine-induced immune thrombotic thrombocytopenia] diagnostics, glucose metabolism diagnostics) and neuropathological examinations were conducted. In 13 deceased, the cause of death was attributed to preexisting diseases while postmortem investigations did not indicate a causal relationship to the vaccination. In one case after vaccination with Comirnaty, myocarditis was found to be the cause of death. A causal relationship to vaccination was considered possible, but could not be proven beyond doubt. VITT was found in three deceased persons following vaccination with Vaxzevria and one deceased following vaccination with Janssen. Of those four cases with VITT, only one was diagnosed before death. The synopsis of the anamnestic data, the autopsy results, laboratory diagnostic examinations, and histopathological and neuropathological examinations revealed that VITT was the very likely cause of death in only two of the four cases. In the other two cases, no neuropathological correlate of VITT explaining death was found, while possible causes of death emerged that were not necessarily attributable to VITT. The results of our study demonstrate the necessity of postmortem investigations on all fatalities following vaccination with COVID-19 vaccines. In order to identify a possible causal relationship between vaccination and death, in most cases an autopsy and histopathological examinations have to be combined with additional investigations, such as laboratory tests and neuropathological examinations.

Levels of haemolysis have no effect on femoral vein post-mortem tryptase levels

Haemolysis is reported to be an artefact that may alter post-mortem tryptase levels. However, previous studies did not sample peripheral blood using newly standardised methods. Recent studies have shown that some previously recognised peri- and post-mortem confounders can be muted by careful sample collection with first clamping and then sampling the femoral vein. This prospective study investigated the relationship between the degree of haemolysis of the blood samples and femoral vein post-mortem tryptase levels when sampled using this recommended method. Seventy consecutive post-mortem tryptase levels in non-anaphylactic deaths were compared to the degree of haemolysis of these samples, and results showed no significant correlation between them. The mean post-mortem tryptase level was 9.5 μg/L. This study demonstrated that the effects of haemolysis on femoral vein post-mortem tryptase was negligible when the blood was sampled using the recommended sampling method. Future studies on post-mortem tryptase as well as other typically used blood markers in forensics are recommended to adopt this method of blood sampling in routine practice.

Fatal food-induced anaphylaxis: Determination of tryptase and specific IgE on cadaveric blood samples. What else for a better methodological standard?

Post-mortem investigation in cases of fatal anaphylaxis is required to provide clarifications on the presence of macroscopic pathological changes, histological features, and immunohistochemical positivity suggestive of the diagnosis, on biochemical evidence of anaphylaxis and on the presence of serological data indicative of the allergen responsible for the anaphylactic reaction. We describe the case of a 16-year-old boy with a medical history of allergic asthma, celiac disease, and known food-induced allergy for fish, fresh milk, peanuts, hazelnuts, walnuts, apples, kiwis, and peaches. Acute onset of dyspnea followed by cyanosis of the lips and respiratory failure was described immediately after having an ice cream sandwich. Unsuccessful rescues were immediately attempted with oral administration of betamethasone, intramuscular injection of adrenaline, and cardiopulmonary resuscitation. A complete post-mortem examination was performed. Serum dosage of mast cell beta-tryptase from femoral blood detecting serum values of 41.4 mg/l. Determination of specific IgE on cadaveric blood samples confirmed the anamnestic data related to sensitization for several food allergens, including cod parvalbumin, tropomyosin, brazil nut, omega-5-gliadin of foods derived from wheat and gluten. The cause of death was identified in a cardiorespiratory failure due to anaphylactic shock in a poly-allergic subject and anaphylaxis was ascribed to the wheat contained in the ice cream sandwich eaten immediately before the onset of respiratory symptoms. The need is to implement an interdisciplinary approach capable to ascertain the sensitivity and specificity of the diagnostic tests currently in use as well as to evaluate the possibility of introducing new biomarkers in practice.

Deaths associated with newly launched SARS-CoV-2 vaccination (Comirnaty®)

Since 27th December 2020, a mRNA vaccine from BioNTech / Pfizer (Comirnaty®) has been used across Germany. As of 12th March 2021, 286 fatalities of vaccinated German individuals were registered at the Paul-Ehrlich-Institute with time intervals after vaccination between one hour to 40 days. From our catchment area in northern Germany, we have so far become aware of 22 deaths in connection with vaccination in a 5 week period (range: 0-28 days after vaccination). Three death cases after vaccination with Comirnaty®, which were autopsied at the Institute of Legal Medicine Hamburg, are presented in more detail. All three deceased had severe cardiovascular diseases, among other comorbidities, and died in the context of these pre-existing conditions, while one case developed a COVID-19 pneumonia as cause of death. Taking into account the results of the postmortem examination a causal relation between the vaccination and the death was not established in any case. If there are indications of an allergic reaction, histological and postmortem laboratory examinations should be performed subsequent to the autopsy (tryptase, total IgE, CRP, interleukin-6, complement activity C3/C5).

Medicolegal Implications of Biphasic Anaphylaxis

ABSTRACT

Biphasic anaphylaxis is an uncommon IgE-mediated condition whose pathophysiological mechanisms, risk factors, and predictive signs are not properly understood. Fortunately, the lethality of biphasic anaphylaxis, although probably underestimated, is low. Preventive clinical measures for biphasic anaphylaxis are neither standardized nor commonly applied. Furthermore, there are no laboratory protocols or anaphylactic markers to help identify the onset of biphasic anaphylaxis in clinical settings. The aim of this review is to highlight the medicolegal difficulties facing coroners and forensic pathologists in terms of the diagnosis and assessment of harm for victims and survivors of biphasic anaphylaxis.

Differences Between Central and Peripheral Postmortem Tryptase Levels

ABSTRACT

Postmortem tryptase is a commonly used biochemical test to aid in the diagnosis of fatal anaphylaxis, which is currently recommended to be sampled from peripheral (femoral) veins because of a research showing comparatively elevated levels from central blood sources. Previous studies have used nonstandardized or nondocumented sampling methods; however, more recent research demonstrates that tryptase levels may vary depending on the sampling method. This study used the recommended sampling method of aspirating the femoral vein after clamping and compared in a pairwise comparison with aspiration of central venous and arterial blood sources (inferior vena cava and aorta) in 2 groups of 25 nonanaphylactic deaths. We found no statistically significant differences in postmortem tryptase between central and femoral vein blood; however, sporadic outliers in central blood (particularly aortic blood reaching levels above documented cutoffs for fatal anaphylaxis) were observed. Our findings provide evidence for the existing recommendations that femoral vein blood remains the preferred sample for postmortem tryptase over central blood.

Fatal anaphylactic shock: A review of postmortem biomarkers and diagnostics

Diagnosing anaphylactic shock postmortem is challenging since differential diagnoses exist and the forensic pathologist often faces subtle findings and lacks relevant information which prevents reaching an opinion of certainty. This review provides an overview of the literature covering research and existing recommendations on the postmortem diagnosis of anaphylactic shock. In order to harmonize the approach and provide guidance for diagnosing deaths from anaphylactic shock in the six forensic centers in Sweden, a guidance protocol aligned with the notion of a holistic view in the approach was devised. Areas in need of further studies include both immunohistological and biochemical investigations to stratify quantitative approaches based on condition and anaphylactic trigger and to lay the ground for and possibly establish alternative matrices.

Anaphylactic Death: A New Forensic Workflow for Diagnosis

Anaphylaxis is a life-threatening or fatal clinical emergency characterized by rapid onset, and death may be sudden. The margin of certainty about the diagnosis of anaphylactic death is not well established. The application of immunohistochemical techniques combined with the evaluation of blood tryptase concentrations opened up a new field of investigation into anaphylactic death. The present study investigated eleven autopsy cases of anaphylactic death, carried out between 2005 and 2017, by the Departments of Forensic Pathology of the Universities of Foggia and Catania (Italy). An analysis of the medical records was carried out in all autopsies. Seven autopsies were carried out on males and four on females. Of the eleven cases, one showed a history of asthma, one of food ingestion, two of oral administration of medications, six did not refer any allergy history, and one subject was unknown. All cases (100%) showed pulmonary congestion and edema; 7/11 (64%) of the cases had pharyngeal/laryngeal edema and mucus plugging in the airway; only one case (9%) had a skin reaction that was found during external examination. Serum tryptase concentration was measured in ten cases, and the mean value was 133.5 µg/L ± 177.9. The immunohistochemical examination using an anti-tryptase antibody on samples from the lungs, pharynx/larynx, and skin site of medication injection showed that all cases (100%) were strongly immunopositive for anti-tryptase antibody staining on lung samples; three cases (30%) were strongly immunopositive for anti-tryptase antibody staining on pharyngeal/laryngeal samples; and eight cases (80%) were strongly immunopositive for anti-tryptase antibody staining on skin samples. We conclude that a typical clinical history, blood tryptase level >40 µg/L, and strongly positive anti-tryptase antibody staining in the immunohistochemical investigation may represent reliable parameters in the determination of anaphylactic death with the accuracy needed for forensic purposes.

Post mortem tryptase: A review of literature on its use, sampling and interpretation in the investigation of fatal anaphylaxis

Post mortem tryptase is a commonly-used ancillary test in the investigation of possible anaphylactic deaths. Ante mortem tryptase interpretation differs from post mortem interpretation due to differing priorities, biochemical behaviours and capacity for follow-up. Additionally, post mortem tryptase sampling site, method and even cut-off levels are not standardised between facilities. This review of the literature investigates the existing research and recommendations on the use of post mortem tryptase in suspected anaphylactic deaths. Currently, autopsy recommendations suggest early sampling, standardised sampling technique with clamping of and aspiration from the femoral vein, and for the results to be interpreted within the wider autopsy and clinical context. Areas in need of further research include the effects of cytolysis on tryptase levels and studies to stratify differing tryptase levels based on type of death and anaphylactic trigger.

Postmortem Tryptase Level in 120 Consecutive Nonanaphylactic Deaths: Establishing a Reference Range as <23 μg/L

Postmortem tryptase is a useful biochemical test to aid the diagnosis of anaphylaxis. Multiple perimortem and postmortem factors have been documented to cause an elevation in postmortem tryptase level. One factor that was recently recognized to have an impact on postmortem tryptase level is correct sampling technique. A recent study recommended aspirating blood samples from a clamped femoral/external iliac vein to be used for reliable postmortem tryptase analysis. This study sampled 120 consecutive nonanaphylactic deaths in which all the peripheral bloods were sampled as recommended. Postmortem interval, resuscitation, different nonanaphylactic causes of death, sex, and age did not show any statistical significant relation to postmortem tryptase level in Student t test, Pearson correlation, and univariate and multivariate analyses. The mean (SD) postmortem tryptase level was 8.4 (5.2) μg/L (minimum, 1.0 μg/L; maximum, 36.1 μg/L; median, 7.3 μg/L). Using nonparametric methods, the postmortem tryptase reference range in nonanaphylactic death was established as <23 μg/L (97.5th percentile).