Residential NO₂ exposure is associated with urgent healthcare use in a thunderstorm asthma cohort

BACKGROUND: There is increasing interest in the role of traffic-related air pollution (TRAP) in allergic airway diseases. Few studies investigate the relationship between TRAP exposure and acute exacerbations of asthma. OBJECTIVE: The 2016 Melbourne thunderstorm asthma epidemic provided an opportunity to investigate the relationship between proxies of TRAP exposure and asthma exacerbation requiring urgent healthcare in the previous 12 months. METHODS: Current asthmatics who presented to the 3 Emergency Departments of Melbourne's second-largest health service with epidemic thunderstorm asthma in November 2016 were identified and completed a standard questionnaire. Their residential addresses were geocoded and the annual average nitrogen dioxide (NO2) exposure for each patient was assigned using a validated satellite-based land use regression model. Residential distance to the nearest major road was calculated using ArcGIS. Multivariate logistic regression was used to investigate the relationship between each TRAP proxy and healthcare use, adjusting for potential confounders. RESULTS: From 263 thunderstorm asthma patients, 88 patients identified with current asthma were analysed. Those with higher mean annual residential NO2 exposure had greater odds of urgent healthcare use in the previous year (odds ratio [OR], 3.45 per one interquartile-range increase; 95% confidence interval [CI], 1.31–9.10; p = 0.01), however distance from major road (OR, 0.95 per 100-m increase; 95% CI, 0.80–1.13; p = 0.57) and living < 200 m from a major road (OR, 1.47; 95% CI, 0.29–7.45; p = 0.64) were not significantly associated. CONCLUSION: In current asthmatics who presented during an epidemic thunderstorm asthma event, greater exposure to residential NO2 was significantly associated with greater odds of asthma exacerbations requiring urgent healthcare in the previous 12 months.

Oral antiplatelet agent hypersensitivity and cross-reactivity managed by successful desensitisation

Oral platelet aggregation inhibitors are widely used for the treatment and prevention of cardiovascular diseases, including coronary stent thrombosis. Premature discontinuation following percutaneous coronary intervention would pose a grave risk of in-stent thrombosis, acute myocardial infarction and eventual death. Although they share the same mechanism of adenosine diphosphate P2Y12 platelet receptor inhibition, they belong to either the chemical class of thienopyridines (clopidogrel, prasugrel, and ticlopidine) or cyclopentyl-triazolo-pyrimidines (ticagrelor and cangrelor). This case describes the first documented cross-reactive hypersensitivity of clopidogrel towards both its fellow thienopyridine, prasugrel, as well as the structurally dissimilar ticagrelor, and its subsequent successful desensitisation.