Usefulness of post mortem determination of serum tryptase, histamine and diamine oxidase in the diagnosis of fatal anaphylaxis

Anaphylactic deaths: A retrospective study of forensic autopsy cases from 2009 to 2019 in Shanghai, China

Anaphylaxis is a rare but well-known cause of sudden unexpected death, although data from forensic autopsies in anaphylactic deaths are limited. Herein, a retrospective study of a series of allergic deaths from 2009 through 2019 in Shanghai, China, was conducted to investigate the demographic, medical, and forensic pathological characteristics of fatal anaphylaxis to improve medicolegal understanding on anaphylactic death. Sixty-two autopsy cases of anaphylactic death were registered in this study. Males dominated the cases (74.2%) against females (25.8%), with an average age of 38.8 years. Medications (98.4%), particularly antibiotics (72.6%), were the most frequent cause of anaphylaxis, and 44 cases (71.0%) occurred in clinics administered illegally by unlicensed clinicians. The anaphylactic symptoms began within a few minutes to less than 1 h in 53 cases, with dyspnea (56.5%) and sudden shock (46.8%) being the most common clinical signs. Thirty cases (48.4%) of anaphylaxis resulted in death within 1 h. Laryngeal edema and multiple tissue eosinophil infiltration (85.5%) were the most prevalent autopsy findings, followed by pulmonary edema and congestion (24.2%), which were considered to be non-specific but suggestive. The comorbidities were mainly cardiovascular disease (33.9%), pneumonia (8.1%) and asthma (8.1%). Serum IgE were measured in 11 of 62 cases, ranging from 43.3 to 591 IU/ml, severed as a helpful marker. Therefore, we suggested a thorough analysis of allergen exposure, clinical history and autopsy findings is required for the diagnosis of anaphylactic death currently.

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.

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

Fatal Food Anaphylaxis: Distinguishing Fact From Fiction

Although there is a general perception that the prevalence of food allergy is increasing, data supporting this are limited. Food is the least common cause of fatal anaphylaxis, and fortunately, it is a very rare event; however, it is also unpredictable. There is widespread consensus that severe reactions cannot be predicted in a clinically meaningful way. Certain food triggers are more frequently associated with fatal anaphylaxis than others. In observational studies, peanut and tree nuts account for at least 30% to 50% of fatalities, with seafood and cow's milk also associated with fatal reactions. Fatal food-induced anaphylaxis is most likely to occur during adolescence and young adulthood, although the reasons for this are unclear. International guidelines agree that intramuscular (IM) epinephrine is the treatment of choice for managing food-triggered anaphylaxis and has a good safety profile when given by the IM route. However, fatalities still occur despite the timely administration of epinephrine. Food-allergic individuals must navigate a world that requires daily vigilance for allergens and preparedness for allergic reactions. Although the actual risk of fatal reactions is minimal, it is not zero, and severe reactions are unpredictable. Clinicians need to help patients better understand the very low but real risk of fatal reaction and enable them to lead as normal a life as possible through appropriate education, safety netting, and risk reduction.

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.

Expression of FcεRIα and tryptase in human lung tissue during drug-induced anaphylactic death

The diagnosis of drug-induced anaphylactic death is an important component of forensic medicine. The purpose of this study was to explore the expression of FcεRIα and tryptase in human lung tissue during drug-induced anaphylactic death and its value for forensic medicine. The expression of FcεRIα and tryptase in lung tissues of the drug-induced anaphylactic death group (n = 30) and control group (who died due to sudden cardiac death, falling from a height, or traffic accidents, n = 30) was detected by immunohistochemistry and immunofluorescence staining. The difference in FcεRIα and tryptase expression in the lung tissue between the drug-induced anaphylactic death group and the control group was statistically significant (p < 0.05). The levels of FcεRIα and tryptase expression greatly increased in the lung tissue of the drug-induced anaphylactic death group, which may provide morphological evidence and a reference for the diagnosis of drug-induced anaphylactic death in forensic medicine.

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.

Reliable Postmortem Molecular Diagnosis of Anaphylaxis: Co-localization of Mast Cell Degranulation and Immunoglobulin E in Allergic Throat Tissues

Anaphylaxis is a serious reaction that may cause death in half an hour without diagnostic characteristic in autopsies. Mast cell (MC) degranulation combined with immunoglobulin E (IgE) plays the key roles in anaphylaxis. Unavailability of serum and instability of measured serum in postmortem diagnoses sometimes limit the opinion of medical experts. Allergic tissues are more accessible than serum, and there is a little research on degranulated mast cells and IgE in different human tissues, whereas we hardly know whether the expression will keep stable over the increasing postmortem interval (PMI). In this research, we examined the mast cell counts and degranulation rates and gE contents in human throat, lung, and intestine tissues and preliminarily investigated the correlation of these markers with PMI in anaphylaxis-associated death. Allergic samples showed a significant increase in mast cell degranulation accompanied by an increase in IgE levels than the control group, but the expression was not significantly correlated with increasing PMI only in throat tissues. Elevated mast cell degranulation combined with increased IgE levels may be a reliable biomarker for forensic diagnosis of human tissues due to IgE-mediated allergic sudden death.

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.

Genetic variants of uncertain significance: How to match scientific rigour and standard of proof in sudden cardiac death?

In many SCD cases, in particular in pediatric age, autopsy can be completely negative and then a post-mortem genetic testing (molecular autopsy) is indicated. In NGS era finding new/rare variants is extremely frequent and, when only variants of unknown significance are found, molecular autopsy fails to find a cause of death. We describe the emblematic case of the sudden death of a 7-year-old girl. We performed a full-body micro-CT analysis, an accurate autopsy, a serum tryptase test and toxicological tests. Since the only macroscopic abnormality we found was a myocardial bridging (length: 1,1 cm, thickness: 0,5 cm) of the left anterior descending coronary artery, a molecular autopsy has been performed. NGS analysis on victim DNA detected rare variants in DPP6, MYH7, SCN2B and NOTCH1 and segregation analysis was then achieved. On the basis of ACMG/AMP (clinical) guidelines, all the found variants were classified as of unknown significance. In other words, both the macroscopic and genetic anomalies we found were of uncertain significance and then the autopsy failed to find the cause of the death. Our case raises three main discussion points: (a) economical, ethical and legal limitations of genetic investigation; (b) risk that genetic testing does not succeed in finding a certain cause of the death; (c) absence of specific guidelines to face the problem of VUS in forensic cases.

Diamine oxidase enzyme: a novel biomarker in respiratory allergy

BACKGROUND

Well-known allergy tests are used to evaluate and diagnose allergic diseases. The aim of this study was to assess the role of serum level diamine oxidase (DAO) enzyme as a diagnostic marker in respiratory allergy.

METHODS

This case-control study included 40 patients with respiratory allergies (atopic asthma and allergic rhinitis) as well as 40 age- and sex-matched controls. A detailed past medical history of allergy was collected from each participant including family history of allergy. Physical examination, pulmonary function test (PFT) and measurement of serum levels of total immunoglobulin E (IgE) and DAO were performed. Skin-prick test and specific IgE to common aeroallergens were also carried out.

RESULTS

DAO levels were higher in patients than controls. There was a positive correlation between severity of disease and DAO. No significant association was found between DAO level and age, type of respiratory allergy, duration of disease, PFT, eosinophilia, and total IgE. DAO had a high negative predictive value (94.7%) and high sensitivity (97.5%).

CONCLUSION

DAO may be helpful in the assessment of severity and in ruling out respiratory allergy.

Evaluation of the distribution of nicotine intravenous injection: an adult autopsy case report with a review of literature

We reported the first comprehensive autopsy case of death due to intravenous injection of nicotine. We examined the distribution of nicotine in the body tissues and fluid and exposed the pathophysiology of nicotine poisoning. A 19-year-old woman was rushed to the hospital in cardiorespiratory arrest and was confirmed dead upon arrival. Liquid nicotine, hydrogen peroxide water, and a syringe were found in the hotel room where she stayed. On autopsy, nicotine concentration was the highest (15,023 μg/mg) in the tissue around the injection mark on the right upper arm. Among the body fluids, the intraperitoneal fluid had the highest, whereas the pericardial fluid had the lowest (0.736 μg/mL) nicotine concentration. Among the organs, the brain had the highest (11.637 μg/mg), whereas the fat tissue had the lowest (1.307 μg/mg) nicotine concentration. The concentration of cotinine, which is the metabolite of nicotine, was the highest in the tissue around the injection mark on the right arm (5.495 μg/mg) and was almost the same among the other body fluids and organs. The respective concentrations of nicotine and cotinine were 1.529 μg/mL and 0.019 μg/mL in the left heart blood and 3.157 μg/mL and 0.002 μg/mL in right heart blood. In this case, the nicotine concentrations in blood reached the lethal level. The distributions of nicotine and cotinine, as indicated by the intravenous injection, were related to the distribution of organs that metabolize nicotine and the distribution of nicotinic acetylcholine receptors.

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

Different sampling techniques can impact on post mortem tryptase levels. A previous study demonstrated significantly lower femoral post mortem total tryptase levels in samples collected via transcutaneous aspiration compared with directly sampling during internal examination. However, an outlier with high tryptase level was noted in one transcutaneous aspiration sample. This 6-month prospective study compared total post mortem tryptase levels between 21 paired aspirated venous and arterial femoral blood samples, and 19 paired aspirated and cutdown femoral venous blood samples in non-anaphylactic deaths only. No statistical differences were demonstrated between the different sampling methods. However, four outlier cases with higher tryptase levels in aspirated arterial and femoral cutdown samples compared with aspirated venous femoral samples were noted. The reasons for the outliers may be due to the bloods collected from these two methods being contaminated by central arterial and venous blood with high tryptase levels respectively. None of the aspirated venous femoral post mortem tryptase levels were above recognized post mortem tryptase cutoff to diagnose anaphylaxis. This study recommends aspirating blood samples from a clamped femoral/external iliac vein for post mortem tryptase analysis should be defined as the gold standard. Further study using the recommended sampling method on post mortem tryptase levels in non-anaphylactic and anaphylactic cases is warranted.

Immune responses in fatalities involving opioids

In some cases of fatalities involving opioid use, the concentrations of detected opioids are not in the toxic range. Immune reactions can be triggered by opioid use, suggesting that immune response may be a factor in these cases. Autopsy cases from 2002–2012 were reviewed. Persons with physical, microscopic or serum evidence of allergic reactions and opioid use at autopsy were compared to persons who used opioids but had no such signs. Overall, 49 persons were identified who had used opioids, of which five had evidence of immune response. A medical history of asthma was significantly more common in persons with signs of immune response (P = 0.0244) and fatality (P = 0.0085) compared to normals. A history of asthma is suggestive of susceptibility to immunologic reactions to opioids, and correlates strongly with the cause of death.

Individualized treatment for allergic rhinitis based on key nasal clinical manifestations combined with histamine and leukotriene D4 levels

Introduction

The types of allergic rhinitis are roughly classified based on the causative antigens, disease types, predilection time, and symptom severity.

Objective

To examine the clinical typing and individualized treatment approach for allergic rhinitis and to determine the optimal treatment method for this disease using various drug combination therapies.

Methods

A total of 108 participants with allergic rhinitis were divided into three groups based on symptoms. Subsequently, each group was further categorized into four subgroups based on the medications received. The efficacy of the treatments was evaluated using the visual analog scale VAS scores of the total and individual nasal symptoms, decline index of the symptom score, histamine and leukotriene levels, and mRNA and protein expression levels of histamine 1 and cysteinyl leukotriene 1 receptors.

Results

Loratadine + mometasone furoate and loratadine + mometasone furoate + montelukast significantly improved the sneezing symptom and reduced the histamine levels compared with the other combination therapies (p < 0.05). Meanwhile, montelukast + mometasone furoate and montelukast + mometasone furoate + loratadine considerably improved the nasal obstruction symptom and decreased the leukotriene D4 levels compared with the other combination therapies (p < 0.05).

Conclusion

Clinical symptom evaluation combined with experimental detection of histamine and leukotriene levels can be an objective and accurate method to clinically classify the allergic rhinitis types. Furthermore, individualized treatment based on allergic rhinitis classification can result in a good treatment efficacy.

Intra-individual alterations of serum markers routinely used in forensic pathology depending on increasing post-mortem interval

Post-mortem biochemistry of serum markers has been the subject of numerous studies, but in-situ marker stability after death has not been sufficiently evaluated yet. Such laboratory analyses are especially necessary in the cases of functional deaths without morphological evidence of the death causes and also in cardiac death cases with only very short survival times. The aim of the study was to determine the post-mortem stability of commonly-used serum markers at predefined time points. In 20 cases, peripheral venous samples were taken starting immediately after circulatory arrest and ending 48 hours after death. Serum creatinine, urea, 3-β-hydroxybutyrate, tryptase, myoglobin, troponin T, creatin kinase and creatin kinase-MB have been included. For all markers, we observed increasing marker levels for longer post-mortem intervals. Significant marker level changes began two hours after death. Excessive increases were observed for cardiac and muscle markers. Marker levels showed high intra-assay precision. Furthermore, the markers were robust enough to withstand freeze-thaw cycles. Potential contamination of arteriovenous blood did not influence the post-mortem marker levels. Post-mortem blood should be sampled as soon as possible, as increased post-mortem intervals may heavily change marker levels in-situ in individual cases, whereas the markers are mostly unaffected by laboratory conditions.

Pericardial Cyst: Cause of Sudden Cardiac Death?

Cardiovascular disease is the leading cause of sudden death in the world. The etiology of sudden cardiac death involves a wide range of diseases, but seldom pericardial cysts. A pericardial cyst is an uncommon cyst usually located in the middle mediastinum and rarely in the posterior part. They are usually harmless and asymptomatic. Here, we present a case of a 63-year-old woman who presented with dyspnea and hoarseness, but died suddenly after a CT scan was attempted. The detailed forensic pathologic and histologic examination revealed a pericardial cyst located in the posterior mediastinum. Toxicology and biochemistry tests, including tryptase, found no competing cause of death.

Diagnostic role of serum tryptase in anaphylactic deaths in forensic medicine: a systematic review and meta-analysis

Postmortem diagnosis of sudden death due to anaphylaxis can be very difficult due to the non-specific pathological findings in forensic practice. Postmortem serum tryptase has been used as an indicator of possible ante-mortem anaphylaxis. Though many previous studies have been conducted to explore the diagnostic significance of serum tryptase for lethal anaphylaxis, inconsistent results were documented. In this study, we made a retrospective study and presented a systematic review and meta-analysis that aims to summarize the diagnostic significance of postmortem serum tryptase in the deceased with and without anaphylactic shock and to calculate a cutoff value for future reference in the identification of deaths due to anaphylactic shock. A complete literature search in the PubMed, Cochrane Library, CNKI and Embase databases (published prior to March 1st, 2017) was performed. The quality of the eligible literature was evaluated according to the Newcastle-Ottawa Quality Assessment Scale (NOS), and the relevant data was extracted. The procedure of meta-analysis was performed by RevMan 5.3 software. Subgroup analysis was performed according to different causes of death. A total of nine studies with 296 patients were identified. The NOS of each included study was equal to 7. The results indicated that high concentrations of tryptase were significantly associated with anaphylactic shock when compared to the other causes of death. The weighted mean difference (WMD) was 29.53 (95% CI = 7.58-51.47, p = 0.008). Similar results were detected in the subgroup analysis when compared to deaths due to cardiovascular disease (CVD). However, no obvious elevation of tryptase in decedents with CVD compared to the other cause of death was observed (WMD = 4.42, 95% CI = -0.94-9.79). We concluded that high serum tryptase is a promising diagnostic biomarker for deaths due to anaphylactic shock, especially when it is higher than 30.4 μg/L.

Post mortem tryptase cut-off level for anaphylactic death

Serum mast cell tryptase is used to support the diagnosis of anaphylaxis. The recommended clinical cut-off for total tryptase (<11.4μg/L) appears unsuitable in the post mortem setting due to largely unknown processes which result in significantly elevated levels in these samples. Consequently there is no widely accepted tryptase cut-off level for diagnosing an anaphylactic death. This 5-year retrospective study compared total tryptase levels in post mortem femoral blood in anaphylactic deaths and control. Univariate and multivariate analysis was used to assess the relative contribution of other factors (age, gender, post mortem interval, and presence of resuscitation) on post mortem tryptase levels. Nine anaphylactic deaths and 45 controls were identified. Receiver-operating characteristic (ROC) curve analysis identified an optimal cut-off of 53.8μg/L, with sensitivity of 89%, and specificity of 93%, for total post mortem tryptase in femoral blood to diagnosis anaphylaxis. No other factors showed any statistical significant contribution to post mortem tryptase elevation. Femoral total post mortem tryptase level of 53.8μg/L and above is a useful ancillary test in diagnosing an anaphylactic death.

Vaccination and anaphylaxis: a forensic perspective

Aim

To review the available literature pertaining to fatalities following vaccine administration and, in particular, cases of vaccine-related fatal anaphylaxis.

Method

The MEDLINE database was systematically searched up to March 2016 to identify all relevant articles pertaining to fatal cases of anaphylaxis following vaccine administration.

Results

Six papers pertaining to fatal anaphylaxis following vaccination were found relevant. Mast cell tryptase and total IgE concentration was assessed exclusively in one case. Laryngeal edema was not detected in any of these cases, whereas eosinophil or mast cell infiltration was observed in lymphoid organs. In one case, immunohistochemical investigations using anti-tryptase antibodies allowed pulmonary mast cells and degranulating mast cells with tryptase-positive material outside to be identified.

Conclusion

In any suspected IgE-mediated fatal anaphylactic cases, biochemical investigations should be systematically performed for forensic purposes. Splenic tissue should be routinely sampled for immunohistochemical investigations in all suspected anaphylaxis-related deaths and mast cell/eosinophil infiltrations should be systematically sought out in the spleen, myocardium, and coronary artery wall. The hypothesis of fatal anaphylaxis following vaccination should be formulated exclusively when circumstantial data, available medical records, laboratory investigations, and autopsy or histology findings converge in a consistent pattern. The reasonable exclusion of alternative causes of death after all postmortem investigations is also imperative in order to establish or rule out a cause-and-effect relationship between vaccine administration and any presumptive temporarily-related death.

Biodistribution of diphenhydramine in reproductive organs in an overdose case

Motion sickness medications such as Travelmin^® prescribed in Japan include diphenhydramine (DPH), dyphylline, diphenidol, and/or caffeine. Herein, we report a patient who died due to rhabdomyolysis after ingesting a DPH containing motion sickness medication. A Japanese male in his 30 s reported missing after going out for a drive early in the morning was found dead in his car in the evening of the same day. An autopsy showed moderate edema, congestion, and several petechiae in both lungs. The brain was congested and edematous with no atherosclerosis of cerebral arteries. The prostate and both testes were slightly edematous. Gastric contents included approximately 15 mL of dark-brown fluid without tablets or food residue. Toxicological examination showed that blood DPH levels in all tissues were between 4.90 and 7.27 μg/mL, which represented toxic to lethal levels. DPH (μg/mL) levels were approximately 3-9 times higher in the prostate (73.42) and testes (left, 28.23; right, 30.09) than those in all regions of the brain (range 7.75-12.33). Blood dyphylline, diphenidol and caffeine levels in reproductive organs reached high, but not toxic levels. In conclusion, DPH, dyphylline, diphenidol, and caffeine levels were higher in reproductive organs such as the prostate and testes than in the central nervous system and heart. As we determined in this case, motion sickness medications might accumulate in reproductive organs. Thus, further examination of tissue biodistribution of DPH, dyphylline, diphenidol, and caffeine is necessary to assess their potential long-term effects in these sites.

How to interpret mast cell tests

Mast cell tryptase (tryptase) is an enzyme produced almost exclusively by mast cells that is easy to measure using a widely available test. In this article we discuss the physiology of the mast cell and how that relates to IgE-mediated anaphylaxis and mastocytosis. We also describe the technical aspects of testing tryptase and the reported normal ranges in health. Finally we explore the diagnostic performance of serum mast cell tryptase measurements, when used to confirm anaphylaxis, estimate future anaphylaxis risk and in diagnosing/monitoring leukaemia.

A Decline in 2 Consecutive Postmortem Serum Tryptase Levels in an Anaphylactic Death

The diagnosis of anaphylaxis in the postmortem setting remains a significant challenge for pathologists. The performance of postmortem serum tryptase is commonly used in the investigation of suspected anaphylactic deaths; however, not only have tryptase levels been found to be elevated in nonanaphylactic deaths, the effect of the postmortem interval on serum tryptase is not fully understood. There are no studies on serial measurement of tryptase in the postmortem setting. We report a death from anaphylaxis in which 2 separate serum tryptase measurements taken 24 hours apart from the same femoral vein showed a substantial decline from 130.0 ug/L at day 2 after death to 84.4 ug/L at day 3. We hypothesize that the decline may be due to degradation of the degranulated mast cell tryptase in anaphylactic deaths. Serial measurement of postmortem serum tryptase may assist in understanding the complex field of serum tryptase interpretation in the postmortem setting. We suggest that an early blood sample to be obtained as soon as possible after death in cases where anaphylaxis is suspected, because there appears to be a significant decline in tryptase levels with increasing postmortem interval.

Postmortem biochemistry: Current applications

The results of biochemical analyses in specimens obtained postmortem may aid death investigation when diabetic and alcoholic ketoacidosis is suspected, when death may have been the result of drowning, anaphylaxis, or involved a prolonged stress response such as hypothermia, and in the diagnosis of disease processes such as inflammation, early myocardial infarction, or sepsis. There is often cross-over with different disciplines, in particular with clinical and forensic toxicology, since some endogenous substances such as sodium chloride, potassium chloride, and insulin can be used as poisons. The interpretation of results is often complicated because of the likelihood of postmortem change in analyte concentration or activity, and proper interpretation must take into account all the available evidence. The unpredictability of postmortem changes means that use of biochemical measurements in time of death estimation has little value. The use of vitreous humour is beneficial for many analytes as the eye is in a physically protected environment, this medium may be less affected by autolysis or microbial metabolism than blood, and the assays can be performed with due precaution using standard clinical chemistry analysers. However, interpretation of results may not be straightforward because (i) defined reference ranges in life are often lacking, (ii) there is a dearth of knowledge regarding, for example, the speed of equilibration of many analytes between blood, vitreous humour, and other fluids that may be sampled, and (iii) the effects of post-mortem change are difficult to quantify because of the lack of control data. A major limitation is that postmortem vitreous glucose measurements are of no help in diagnosing antemortem hypoglycaemia.

Amniotic fluid embolism pathophysiology suggests the new diagnostic armamentarium: β-tryptase and complement fractions C3-C4 are the indispensable working tools

Amniotic fluid embolism (AFE) is an uncommon obstetric condition involving pregnant women during labor or in the initial stages after delivery. Its incidence is estimated to be around 5.5 cases per 100,000 deliveries. Therefore, this paper investigated the pathophysiological mechanism, which underlies AFE, in order to evaluate the role of immune response in the development of this still enigmatic clinical entity. The following databases (from 1956 to September 2014) Medline, Cochrane Central, Scopus, Web of Science and Science Direct were used, searching the following key words: AFE, pathophysiology, immune/inflammatory response, complement and anaphylaxis. The main key word “AFE” was searched singularly and associated individually to each of the other keywords. Of the 146 sources found, only 19 were considered appropriate for the purpose of this paper. The clinical course is characterized by a rapid onset of symptoms, which include: acute hypotension and/or cardiac arrest, acute hypoxia (with dyspnoea, cyanosis and/or respiratory arrest), coagulopathies (disseminated intravascular coagulation and/or severe hemorrhage), coma and seizures. The pathology still determines a significant morbidity and mortality and potential permanent neurological sequelae for surviving patients. At this moment, numerous aspects involving the pathophysiology and clinical development are still not understood and several hypotheses have been formulated, in particular the possible role of anaphylaxis and complement. Moreover, the detection of serum tryptase and complement components and the evaluation of fetal antigens can explain several aspects of immune response.

Food allergy testing

Food allergy (IgE-mediated hypersensitivity) is a common clinical problem affecting approximately 15% of children in the Western world. These hypersensitivity reactions tend to be "immediate" (typically within minutes of food exposure), and clinical features may range from mild to life threatening (anaphylaxis). Detailed clinical history is critical to correct diagnosis. Available laboratory tests have limitations not least poor positive predictive value and limited repertoire. Laboratory tests should support clinical diagno sis not vice versa.

Measurement of β-tryptase in postmortem serum, pericardial fluid, urine and vitreous humor in the forensic setting

In the realm of forensic pathology, β-tryptase measurement for diagnostic purposes is performed in postmortem serum obtained from femoral blood. This may be partially or completely unavailable in some specific cases, such as infant autopsies and severely damaged bodies. The aim of this study was to investigate the usefulness of determining β-tryptase levels for diagnostic purposes in alternative biological samples. Urine, vitreous humor and pericardial fluid were selected and measured in 94 subjects including: fatal anaphylaxis following contrast material administration (6 cases), hypothermia (10 cases), diabetic ketoacidosis (10 cases), gunshot suicide (10 cases), heroin injection-related deaths (18 cases), trauma (10 cases), sudden death with minimal coronary atherosclerosis (10 cases), severe coronary atherosclerosis without myocardial infarction (10 cases) and severe coronary atherosclerosis with myocardial infarction (10 cases). Postmortem serum and pericardial fluid β-tryptase levels higher than the clinical reference value (11.4ng/ml) were systematically identified in fatal anaphylaxis following contrast material administration and 6 cases unrelated to anaphylaxis. β-tryptase concentrations in urine and vitreous humor were lower than the clinical reference value in all cases included in this study. Determination of β-tryptase in pericardial fluid appears to be a possible alternative to postmortem serum in the early postmortem period when femoral blood cannot be collected during autopsy and biochemical investigations are required to objectify increased β-tryptase levels.

Risk of anaphylaxis in opioid dependent persons: effects of heroin versus substitution substance

Background

Across Europe, illicit drug-related mortality has not declined despite ever increasing prevention measures. The cause of these deaths has traditionally been associated with overdose. Previous findings have revealed the appearance of non-lethal opioid concentrations, leading us to investigate a further cause of death. The symptoms of heroin intoxication with asphyxia and/or cardiovascular involvement resemble anaphylaxis, and therefore it has been speculated that such deaths might be caused by an allergic reaction. The study´s aims were to investigate levels of allergic mediators in long-term injecting drug users (IDU) compared to healthy controls and to determine if oral opioid substitution therapy (OST) resulted in similar allergic symptoms to those reported by IDU after intravenous (IV) heroin use.

Methods

We quantified the concentrations of histamine, diamine oxidase (DAO), tryptase and lipoprotein-associated phospholipase A₂ (LpPLA₂) at baseline and 1 h after administration of Substitol®retard (482 ± 220 mg) in 56 patients at a withdrawal centre (Austria) and compared them with healthy controls (n = 103). Questionnaires and face-to-face interviews were used to assess allergic symptoms and side effects in IDU. Descriptive statistical analyses of quantitative data were performed by using SPSS.

Results

Baseline histamine, tryptase and LpPLA₂ were significantly elevated in IDU compared to the healthy control group, while DAO decreased. Blood levels showed no significant change after oral substitution uptake. Self-reported allergic symptoms and side effects after IV heroin use were reported in 55 cases (98.2%), minimal symptoms were documented after OST (12.5%, 7/56).

Conclusions

This study revealed that baseline histamine concentrations were elevated in chronic IDU, although only relatively small changes in tryptase plasma levels occurred. After IV heroin application the reported allergic symptoms were mostly mild and did not lead to clinically relevant side effects. The substitution substance was clearly better tolerated than IV administered heroin. Elevated levels of allergic mediators such as histamine in IDUs may place them at greater risk of severe or fatal anaphylaxis when exposed to heroin; however, this requires further investigation.

Pediatric Natural Deaths

Autopsies are important in the investigation of childhood deaths. Most natural deaths are unlikely to come to the attention of the forensic pathologist, particularly in cases where death occurs in hospital. During the neonatal period (up to 28 days of age), deaths most commonly occur as a result of prematurity and related conditions, chromosomal abnormalities, or congenital malformations. Beyond the neonatal period, trauma-related deaths and sudden infant death syndrome are more common. In terms of natural acquired diseases of childhood, certain conditions are prevalent based on age and may be encountered at autopsy. Common acquired diseases that cause death in infants and children up to 5 years of age include pneumonia and other respiratory diseases, other infectious diseases, and malignancies. In older children, mortality due to natural disease declines substantially with trauma being the major cause of death, and malignancies the major cause of acquired disease. Sudden and/or unexpected deaths in which a natural disease state was previously unknown are most likely to come under the jurisdiction of the medical examiner or coroner and may be related to an underlying natural disease. Depending on the underlying disease process, the approach can differ, and therefore familiarity with common causes of death during childhood is important in order to focus the autopsy so that special techniques can be used along with obtaining proper ancillary testing to arrive at an accurate diagnosis and cause of death.

Sudden death due to hydatid disease: a six-year study in the northern part of Tunisia

Human ecchinococcosis also known as hydatid disease is a zoonotic infection caused by the tapeworm Ecchinococcus with 2-3 Million cases worldwide. We hereby report a 6 years period study of Sudden death due to hydatidosis aiming to analyze the epidemiological criteria, death circumstances, and autopsy observations attributed to hydatid disease. During the past 6 years, 26 death cases were due to hydatid disease. Our analysis shows that the sex ratio (M/F) was 1.6, the mean age was 31-year old, and 65% of the subjects lived in rural places. In 17 cases, death occurred in the victim's place, five victims died after a heavy exercise, and in two cases, death occurred immediately after trauma. At autopsy, 91% of the cysts were found in the liver. In three cases, death followed a septic state, and in two cases, it followed an acute respiratory failure. Death was attributed to anaphylaxis in 17 cases.

Postmortem serum tryptase levels in anaphylactic and non-anaphylactic deaths

BACKGROUND

The postmortem diagnosis of anaphylaxis remains difficult due to the lack of specific biomarkers. Mast cell tryptase (MCT) levels are used as a marker of mast cell degranulation in living patients and elevated levels have also been described in postmortem serum samples in anaphylaxis-associated deaths, although elevated levels may also be seen in non-anaphylaxis-associated deaths.

OBJECTIVE

To investigate the effects of cause of death, site of blood sampling, degree of sample haemolysis and the presence of opiates on postmortem MCT levels.

METHOD

We obtained sera from three collection sites from 189 non-suspicious coronial postmortems and aortic samples from 10 anaphylactic deaths to characterise postmortem MCT.

RESULTS

MCT were elevated (>11.4 μg/L) in 57% of aortic samples, 58% of femoral samples and 30% of subclavian samples. In aortic samples, there were significantly higher levels of MCT in anaphylaxis-associated deaths compared with other causes of death. Aortic MCT levels >110 μg/L had a sensitivity of 80% and specificity of 92.1% for anaphylaxis-associated deaths. There was a significant correlation between MCT and degree of sample haemolysis but no correlation with the presence of opiates.

CONCLUSIONS

Moderately elevated MCT levels are common in postmortem sera. Aortic values >110 μg/L may support a diagnosis of anaphylaxis-associated death, although the diagnosis should not be based on this test alone. There was significant variation between sample sites and reference ranges for individual sample sites should be established.

Mediators released during human anaphylaxis

A range of mediators are generated during anaphylaxis, with redundancy of effects, multiple overlapping pathways, and involvement of several cell types. Key steps in the reaction occur at the site of initial contact, and mediators may not be detectable systemically. Furthermore, the potencies of various mediators vary enormously, and clinical effects may occur below our level of detection. We also do not know what converts (amplifies) a local reaction into systemic anaphylaxis. Murine models have identified several novel mediators that may propagate and/or regulate this process and also indicate that circulating neutrophils may play an important role in reaction amplification. Differential expression of various genes within specific intracellular signalling pathways of mediator release may further explain the varying severities of anaphylactic reactions. As our knowledge of the mechanisms of activation, key mediators, and the regulation of mediator release improves, new treatments for prevention and acute management may emerge.