Search

Forensic series on fatal anaphylaxis are scarce, probably because the diagnosis of anaphylaxis is often complex and the incidence is low. We report on the medicolegal, demographic and histopathological characteristics of a series of sudden deaths which were investigated for anaphylaxis at the Spanish National Institute of Toxicology and Forensic Sciences (INTCF) over a 17-year period (1998-2015). A total of 122 undetermined sudden deaths from a high percentage of Spanish regions (81.5% of the total population) were sent to the INTCF with anaphylaxis as the suspected cause of death for histological, biochemical, and medicolegal investigation. Two certified allergists confirmed that 46 of the 122 cases were fatal anaphylaxis. The results indicated a median age of 51 years (IQR = 29) and a male predominance (76%). The main causes of anaphylaxis were drugs (41%), hymenoptera stings (33%), and food (13%). A previous allergic event had been reported in both food anaphylaxis (67%) and drug anaphylaxis (53%). The deaths occurred in health care settings (37%), at home (22%), and outside the home (26.09%). Histopathology data were available for 40 individuals. The most frequent autopsy findings were angioedema of the upper airways (50%), pulmonary edema (47.5%), atheromatosis of coronary vessels (32.5%), and pulmonary congestion (27.5%). Our findings for fatal anaphylaxis indicated a predominance of men, older age (≥50 years) and death in a health care setting (one-third of cases). Previous episodes had occurred in two-thirds of cases of food-induced anaphylaxis and in half of the cases of drug-induced anaphylaxis.

Background: Beta-blockers (BBs) and angiotensin-converting enzyme inhibitors (ACEIs) have been associated with an increased risk and severity of anaphylaxis. However, the evidence supporting these findings is contradictory., Objective: We carried out a systematic review and meta-analysis of studies that assess the influence of BBs and ACEIs on anaphylaxis., Methods: We searched PubMed/MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, and the Web of Science for relevant observational studies. We searched for studies where the presence and severity of anaphylaxis were compared between patients taking BBs, ACEIs, both types of drug, or neither type of drug. We performed a meta-analysis using a random-effects model., Results: A total of 21 studies met the study criteria. Of these, 15 assessed the severity and 9 the incidence of anaphylaxis. The studies brought together 22,313 anaphylaxis episodes for the severity studies and 18,101 anaphylaxis episodes for the studies of new cases of anaphylaxis. BBs and ACEIs increased the severity of anaphylaxis (BBs, odds ratio [OR] 2.19, 95% confidence interval [CI] 1.25-3.84; ACEIs, OR 1.56, 95% CI 1.12-2.16), but not the presence of new cases of anaphylaxis (BBs, OR 1.40, 95% CI 0.91-2.14; ACEIs, OR 1.38, 95% CI 0.39-4.86). It was not possible to perform an analysis adjusted for cardiovascular diseases, because only 1 study each for BBs and ACEIs, respectively, had adjusted data., Conclusions: The quality of evidence showing that the use of BBs and ACEI increases the severity of anaphylaxis is low owing to differences in the control of confounders arising from the concomitant presence of cardiovascular diseases., (Copyright © 2018 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Reports of fatal anaphylaxis remain scarce because of the rarity of the condition and the fact that information is limited to a few countries., Objective: Our objective was to investigate clinical and demographic characteristics and the causes of fatal anaphylaxis in Spain using two databases of cases of fatal anaphylaxis., Methods: We analysed fatal anaphylaxis in a series from the Spanish hospital system and a series from the National Institute of Toxicology and Forensic Sciences (Instituto Nacional de Toxicología y Ciencias Forenses [INTCF]), which predominantly comprise extrahospital deaths. Deaths from the Spanish hospital system were retrieved from among all deaths occurring during 1998-2011 using codes related to anaphylaxis. Deaths due to anaphylaxis in the INTCF database during the same period were retrieved by 2 allergists, who identified cases in which anaphylaxis was a possible cause of death. A logistic regression model was constructed to predict the characteristics of fatal anaphylaxis in each database., Results: The incidence of death by anaphylaxis in Spain using both databases was 0.25 (95% CI, 0.24-0.26) deaths per million person-years. The most frequent causes of death in the hospital system were drugs (46.1%), unknown causes (40.0%), and foods (10.4%); in the INTCF, the most common causes of death were drugs (47.2%), insect stings (30.6%), and foods (11.1%). The logistic regression model showed that fatal anaphylaxis due to unknown causes (OR 15.2, 95% CI 1.8-129.8) was more likely in the hospital database, whereas insect stings (OR 100, 95% CI 10-833.3) and previous atopic comorbidity (OR 15.2, 95% CI 6.3-33.3) were more likely in the INTCF database., Conclusions & Clinical Relevance: The estimated frequency of fatal anaphylaxis in Spain was among the lowest reported. Future studies of fatal anaphylaxis should use databases from different origins in order to show the considerable heterogeneity in this type of death., (© 2018 John Wiley & Sons Ltd.)

Anaphylaxis is a life-threatening allergic reaction that occurs suddenly after contact with an allergen. Epidemiological studies about anaphylaxis are very important in planning and evaluating new strategies that prevent this reaction, but also in providing a guide to the treatment of patients who have just suffered an anaphylactic reaction. Electronic Medical Records (EMR) are one of the most effective and richest sources for the epidemiology of anaphylaxis, because they provide a low-cost way of accessing rich longitudinal data on large populations. However, a negative aspect is that researchers have to manually review a huge amount of information, which is a very costly and highly time consuming task. Therefore, our goal is to explore different machine learning techniques to process Big Data EMR, lessening the needed efforts for performing epidemiological studies about anaphylaxis. In particular, we aim to study the incidence of anaphylaxis by the automatic classification of EMR. To do this, we employ the most widely used and efficient classifiers in text classification and compare different document representations, which range from well-known methods such as Bag Of Words (BoW) to more recent ones based on word embedding models, such as a simple average of word embeddings or a bag of centroids of word embeddings. Because the identification of anaphylaxis cases in EMR is a class-imbalanced problem (less than 1% describe anaphylaxis cases), we employ a novel undersampling technique based on clustering to balance our dataset. In addition to classical machine learning algorithms, we also use a Convolutional Neural Network (CNN) to classify our dataset. In general, experiments show that the most classifiers and representations are effective (F1 above 90%). Logistic Regression, Linear SVM, Multilayer Perceptron and Random Forest achieve an F1 around 95%, however linear methods have considerably lower training times. CNN provides slightly better performance (F1 = 95.6%)., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background and Objective: Studies assessing the severity of anaphylaxis lack a comprehensive approach to collecting data on comorbidities that may worsen prognosis. Objective: Using the Elixhauser score (a systematic index associated with longer stay, hospital charges, and mortality), we determined which comorbidities were associated with more severe anaphylaxis., Methods: We based our study on the Spanish Ministry of Health database of hospital discharges in Spain between 1997 and 2011. We constructed logistic regression models in which the dependent variables were outcomes related to greater severity (death, cardiac arrest, need for invasive mechanical ventilation or vasopressor drugs, admission to the intensive care unit, and length of stay) and the independent variables were the 30 comorbidities that comprise the Elixhauser score, age, sex, and main causes of anaphylaxis., Results: We found that a higher risk of severe anaphylaxis was associated (3 or more logistic regressions) with age >50 years or having experienced cardiac arrhythmia, coagulation disorder, associated fluid-electrolyte imbalance, chronic pulmonary disease, or Echinococcus anaphylaxis. Likewise, in the adjusted analysis, a higher Elixhauser score was associated with most of the outcomes analyzed for severity of anaphylaxis., Conclusions: Cardiovascular and respiratory diseases increase the severity of anaphylaxis, and the resulting poor health status (represented as a higher Elixhauser score) is associated with more severe anaphylaxis.

Background: Our objective was to ascertain the degree of adherence to recommendations made to patients with anaphylaxis, most of whom were attended in our allergy outpatient clinic., Methods: A questionnaire was sent to 1512 patients who had experienced anaphylaxis and completed by 887. The chosen definition of anaphylaxis was that of the National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network Symposium. We evaluated the prescription, purchase, and use of epinephrine auto-injectors and oral drugs, as well as the avoidance of allergens involved in previous anaphylaxis episodes., Results: Most patients (94.53%) reported that they had received advice on avoidance of responsible allergens after their allergy workup. Epinephrine auto-injectors and oral drugs were prescribed according to the subtype of anaphylaxis. Only 30.74% of patients used the epinephrine auto-injector; 54.26% took oral medication. Most patients (88.3%) avoided the allergen., Conclusions: Despite general agreement that anaphylaxis occurring in the community should be treated with epinephrine auto-injectors, use of these devices to treat recurrences was low in our patients. Oral medication intake was more common than the epinephrine auto-injector in all subtypes. In order to increase adherence to epinephrine auto-injectors, it is necessary to think beyond the measures recommended during regular visits to allergy outpatient clinics.

Knowledge of the epidemiology of anaphylaxis has improved during the last 10 years thanks to the increased number of publications with improved methodological robustness. Consequently, we better understand the distribution and frequency of anaphylaxis and the characteristics of fatal anaphylaxis. We now know that anaphylaxis is more frequent than previously thought (up to 50-103 cases per 100 000 person-years), although the distribution differs with the age group (up to 3 times in patients aged 0-4 years), cause (food-induced anaphylaxis is more frequent in young people, drug-induced and Hymenoptera anaphylaxis in older patients), and geographical area (more prevalent in areas with less sunlight). A controversial and unresolved issue is whether this high incidence of anaphylaxis is a real increase or merely the result of better identification of anaphylaxis by the attending physician. Recurrence of anaphylaxis has been recorded in one-third of cases, although it is the least studied area of the epidemiology of anaphylaxis. Fatal anaphylaxis, on the other hand, has been widely studied. We know that death from anaphylaxis is a rare and extraordinary event (0.12 to 1.06 deaths per million person-years) and more likely in older individuals in the case of drug and Hymenoptera anaphylaxis. Studies conducted during the last 10 years are highly powered since they include large numbers of patients (national records of hospitalized patients) over long time periods (10-20 years) or have been conducted with representative samples of the general population.

Aims: We describe a rare case of anaphylaxis and thrombocytopenia whose cause was heparin used during hemodialysis sessions., Case Report: A 77-year-old woman suffered five consecutive episodes of vomiting, tachypnea, wheezing or rales, immediately after initiating hemodialysis. In the first of these episodes, arterial pressure was undetectable. In all of the episodes there was evidence of the presence of hypoxia (always below 60 mmHg) and thrombocytopenia (always below l00,000/microl,, with partial platelets recovery among episodes. The episodes started immediately after hemodialysis sessions and heparin infusion; either sodium heparin or enoxaparin was used. Utilization of different filters was not able to stop the episodes. These were stopped when a switch from heparin to hirudin was tested. Tryptase levels, as a marker of mast cells activation and anaphylaxis, were not increased in two of the episodes which were assessed. IgG antibodies against heparin-PF4 complex was detected at high levels., Discussion: A diagnosis of concomitant anaphylaxis and thrombocytopenia caused by sodium heparin and a low-molecular weight heparin (enoxaparin) were assumed.