Prognostic factors in outcome of angioedema in the emergency department

Angioedema is a transient, localized swelling caused by two distinct mechanisms, mediated by histamine and bradykinin, respectively, although a proportion of cases remain idiopathic. Studies that characterize undifferentiated angioedema presenting in emergency departments (EDs) are limited. This study investigates the presentation patterns of undifferentiated angioedema in the ED based on the presumed mechanism of swelling. Medical records from all ED visits to two tertiary care hospitals from July 2007 to March 2012 were electronically reviewed. Records with documented visible swelling on general inspection and/or fiberoptic laryngoscopy and a diagnostic code for anaphylactic shock, angioneurotic edema, allergy unspecified, defects in the complement system, or unspecified drug adverse effects were included. Demographic, clinical, and outcome data were collected via a standardized form. Data were analyzed descriptively, including frequencies and percentages for categorical data and means and SDs for continuous data. Predictors for admission were identified using multivariate logistic regression models. ED records from 527 visits for angioedema by 455 patients were included in the study. Annual rate of angioedema was 1 per 1000 ED visits. Urticaria was associated with peripheral (p = 0.008) and lip angioedema (p = 0.001), and the absence of urticaria correlated with tongue angioedema (p = 0.001) and trended toward correlation with pharyngeal angioedema (p = 0.056). Significant predictors of admission included nonsteroidal anti-inflammatory drug-induced angioedema (odds ratio [OR], 15.3), epinephrine treatment (OR, 8.34), hypotension (OR, 15.7), multiple-site angioedema (OR, 4.25), and pharyngeal (OR, 1.23) and tongue angioedema (OR, 4.62). Concomitant urticaria was associated with a significant longer stay in the ED (p < 0.001). The presence of urticaria correlated with the location of angioedema, need for airway management, length of ED visit, and recurrence. A detailed drug and family history, screening blood work for C1 esterase inhibitor deficiency when indicated, and prompt management of angioedema based on presumed mechanism of swelling are crucial steps in managing undifferentiated angioedema in ED.