Emergency department as an observatory of rare diseases: the case of angioedema

Angioedema (AE) is a rare disease, nowadays more common, occurring as an adverse drug reaction. AE is an emergency that brings patients straight to the Emergency Department (ED), which in turn becomes a privileged observatory for this disease. Insufficient knowledge about AE types makes the diagnosis very challenging. Objectives of the study: 1. Evaluate ED admission rate by AE; 2. Identify ED lab tests useful to differential diagnosis; 3. Detect specific clinical symptoms and signs of AE; Materials and methods: It has been conducted a retrospective study at the Emergency Department of the Policlinic Umberto I of Rome from 2013 to 2017. Using the computerized system ICD-9, we collected reports of closed medical records with diagnosis codes of Angioedema, Allergy, and Urticaria. Through exclusion criteria, we identified a sample of 2.012 patients. Recruited patients were divided into 3 groups: drugs-induced angioedema (DRUG-AAE), hereditary angioedema (HAE), histaminergic angioedema (IHAA). Age, gender, onset of symptoms, fibrinogen, CRP, C3, C4, tryptases were also analyzed. We then focused on DRUG-AAE and HAE groups. Results: In the DRUG-AAE group, the average age was 67, 32 +/- SED 2, 77 with M: F ratio of 10:18. In the HAE group, the average age was 49, 6 + SED 5.15 with M: F ratio of 6:7. Using Fisher’s Test we found significant difference (p <0,006) at times of onset of the symptoms, revealing that DRUG-AAE has a more increased prevalence at night then HAE. Among blood chemistry results, ANOVA Test and T Student were significant for fibrinogen values (p < 0, 0001).angioedema, but their statistical significance is not sufficient to steer diagnosis in the absence of other clinical elements. 2. Time of onset of angioedema may have some diagnostic significance only in the case of DRUG-AEE, where time of drug intake may directly lead to the cause of event. No literature was found on these issues. 3. Emergency medical education is the main factor that could discriminate the diagnosis of histaminergic from bradykinin-mediated angioedema