Search

There is no standardized method for assessing serum total mast cell tryptase (MCT) in anaphylaxis. The consensus equation (peak MCT should be>1.2× baseline tryptase+2 mg/L) has been proposed to interpret acute MCT in mast cell activation syndrome (MCAS). To validate consensus equation in a perioperative setting analyses of cases of suspected perioperative anaphylaxis during general anaesthesia (GA) were performed. Anaphylaxis was defined as per World Allergy Organisation (WAO) criteria. Timed serial MCT measurements were mapped against the consensus equation and receiver operating characteristic (ROC) curves produced. A total of 82 patients (60 females, mean age 56.5 years±SD17.2) underwent investigation. Sixty (73%) patients fulfilled WAO criteria for anaphylaxis, and 22 patients did not. Aetiology included 59% IgE-mediated anaphylaxis, 2% non-IgE-mediated anaphylaxis, 12% anaphylaxis of unknown cause and 27% deemed non-anaphylaxis. IgE-mediated anaphylaxis included the following: NMBA (35%), antibiotics (46%), chlorhexidine (8%), patent blue dye (8%) and others (8%). An acute MCT with a comparable baseline was available in 71 of 82 (87%) patients (60 anaphylaxis and 11 controls). The median interquartile range (IQR) time from reaction to peak MCT was 1.34 (0.82-2.51) hours. Analyses confirmed that a rise in acute MCT greater than that defined by the equation had a sensitivity, specificity, positive predictive value (PPV) and negative (N) PV of 78%, 91%, 98% and 44%, respectively. The magnitude of increase in acute MCT above the threshold predicted by consensus equation was higher in the anaphylaxis group compared to controls (P=.0001). This equation has a high specificity, PPV with a moderate NPV and sensitivity in perioperative anaphylaxis.

BACKGROUND The incidence of anaphylaxis in South Asians (Indian, Pakistani and Bangladeshi ethnicity) is unknown. Birmingham is a British city with a disproportionately large population of South Asians (22.5%) compared with the rest of the UK (4.9%). The main aims of this study were to determine the incidence and severity of anaphylaxis in this population and to investigate the differences between the South Asian and White populations. METHODS A retrospective electronic search of emergency department attendances at three hospitals in Birmingham during 2012 was carried out. Wide search terms were used, medical notes were scrutinized, and the World Allergy Organization diagnostic criteria for anaphylaxis were applied. Patients' age, sex, ethnicity and home postal code were collected, reactions were graded by severity, and other relevant details including specialist assessment were extracted. Multivariate analysis was undertaken using 2011 UK census data. RESULTS Age-, sex- and ethnicity-standardized incidence rate of anaphylaxis was 34.5 per 100 000 person-years. Multivariate logistic regression which controlled for the confounders of age, sex and level of socioeconomic deprivation showed that incidence was higher in the South Asian population (OR 1.48, P = 0.005). Incidence rate in the South Asian population was 58.3 cases per 100 000 person-years compared to 31.5 in the White population. South Asian children were more likely to present with severe anaphylaxis (OR 5.31, P = 0.002). CONCLUSIONS Incidence of anaphylaxis is significantly higher in British South Asians compared to the white population. British South Asian children are at a greater risk of severe anaphylaxis than White children.