Allergic reactions following contrast material administration: nomenclature, classification, and mechanisms

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.

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.

Feasibility and safety of automated CO2 angiography in peripheral arterial interventions

Carbon dioxide (CO2) gas is an established alternative to iodine contrast during angiography in patients with risk of postcontrast acute kidney injury and in those with history of iodine contrast allergy. Different CO2 delivery systems during angiography are reported in literature, with automated delivery system being the latest. The aim of this study is to evaluate the safety, efficacy, and learning curve of an automated CO2 injection system with controlled pressures in peripheral arterial interventions and also to study the patients' tolerance to the system.From January 2018 to October 2019 peripheral arterial interventions were performed in 40 patients (median age-78 years, interquartile range: 69-84 years) using an automated CO2 injection system with customized protocols, with conventional iodine contrast agent used only as a bailout option. The pain and tolerance during the CO2 angiography were evaluated with a visual analog scale at the end of each procedure. The amount of CO2, iodine contrast used, and radiation dose area product for the interventions were also systematically recorded for all procedures. These values were statistically compared in 2 groups, viz first 20 patients where a learning curve was expected vs the rest 20 patients.All procedures were successfully completed without complications. All patients tolerated the CO2 angiography with a median total pain score of 3 (interquartile range: 3-4), with no statistical difference between the groups (P = .529). The 2 groups were statistically comparable in terms of comorbidities and the type of procedures performed (P = .807). The amount of iodine contrast agent used (24.60 ± 6.44 ml vs 32.70 ± 8.70 ml, P = .006) and the radiation dose area product associated were significantly lower in the second group (2160.74 ± 1181.52 μGym2 vs 1531.62 ± 536.47 μGym2, P = .043).Automated CO2 angiography is technically feasible and safe for peripheral arterial interventions and is well tolerated by the patients. With the interventionalist becoming familiar with the technique, better diagnostic accuracy could be obtained using lower volumes of conventional iodine contrast agents and reduction of the radiation dose involved.

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.

Incidence and Risk Factors for Gadolinium-Based Contrast Agent Immediate Reactions

Since their clinical introduction in 1988, gadolinium-based contrast agents (GBCAs) have demonstrated an excellent safety profile with a reported acute adverse reaction rate ranging from 0.01% to 2%. By comparison, the acute adverse reaction rate of low osmolar nonionic computed tomography contrast agents (CTCs) ranges from 0.7% to 3.1%. Many of the risk factors associated with CTC reactions (drug allergies, asthma, atopy, prior contrast reaction) also point toward an increased incidence of acute adverse events to GBCAs. With CTCs, an increased adverse event rate was associated with ionic preparations and high osmolality. In response to concerns for nephrogenic systemic fibrosis, GBCAs are now selected for their augmented chemical stability. These agents possess some combination of macrocyclic chelates or ionic preparations. With their improved chemical stability, these agents also possess higher osmolality and the increased potential to elicit an acute adverse reaction. In light of these concerns, researchers are now focusing greater efforts on reexamining acute adverse reactions to GBCAs and whether there is an increased association with certain agents. In addition to hypersensitivity reactions, this article will also discuss contrast extravasations, safety of GBCAs for pregnant and nursing patients, and the potential nephrotoxic effects of GBCAs.

Postmortem diagnosis of anaphylaxis in presence of decompositional changes

Eosinophil and activated mast cell identification in the spleen combined with mast cell tryptase determination in postmortem serum may diagnose fatal anaphylaxis with a high degree of certainty. Mast cell tryptase measurement and significance in corpses with decompositional changes remains however an issue of controversy. Analogously, immunohistochemistry in corpses with decompositional changes may be influenced by several mechanisms, including protein alteration, antigen diffusion and unspecific antibody binding to disrupted protein structures. The authors present an autopsy case involving a 55-year-old woman who unintentionally received clarithromycin. Due to difficult in administrative procedures, the postmortem examination was performed 96 h after death. Mast cell tryptase was measured in postmortem serum from femoral, aortic and right heart blood. The obtained results were consistent with mast cell activation. Histochemistry (Pagoda Red) and immunohistochemistry (anti-tryptase antibodies) allowed splenic eosinophils and mast cells to be detected. Based on the results of all postmortem investigations, the hypothesis of anaphylaxis following accidental clarithromycin administration was formulated.

Hypersensitivity from intravenous iron products

In the last several years, intravenous therapy with iron products has been more widely used. Although it has been a standard procedure in dialysis-associated anemia since the early 1990s, its use is expanding to a host of conditions associated with iron deficiency, especially young women with heavy uterine bleeding and pregnancy. Free iron is associated with unacceptable high toxicity inducing severe, hemodynamically significant symptoms. Subsequently, formulations that contain the iron as an iron carbohydrate nanoparticle have been designed. With newer formulations, including low-molecular-weight iron dextran, iron sucrose, ferric gluconate, ferumoxytol, iron isomaltoside, and ferric carboxymaltose, serious adverse events are rare.

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.