THU0307 THE HALO SIGN IN THE EMERGENCY DEPARTMENT: COMPLEMENTARY VALUE TO THE APPLICATION OF THE CRITERIA FOR THE CLASSIFICATION OF GIANT CELL ARTERITIS IN AN ACUTE ENVIRONMENT
Authors: Carlos Guillén-Astete, Fernando Lopez-Gutierrez, Ana Rodriguez-García, Carmen Larena, Monica Luque-Alarcón, Jose Luis Morell Hita
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> In a previous study (Acta Reum 2018; Vol.4.No.1:5), we identified the low diagnostic value of the criteria for classification of giant cell arteritis (GCA) in patients with such suspicion in an emergency setting of a third level hospital. In some emergency units, linear probe ultrasound equipment is available for immediate use. It would be of interest to determine whether the training of healthcare personnel in halo sign recognition could be useful in addition to the CGA criteria in situations of suspicion. <h3>Objectives</h3> We present a sub-study in which we incorporate the ultrasound study of temporal atheria (TA) as an added criterion to determine its contribution in terms of diagnostic validation. <h3>Methods</h3> We reviewed the casuistry of patients who consulted the emergency department with different combinations of the rest of the ACG classification criteria, included in the aforementioned study. The entry requirements were: Age &gt; 40 years and headache as a reason for consultation. We identified those patients who underwent temporal artery ultrasound during assessment before receiving corticoid therapy. The pattern of comparison was the definitive diagnosis of ACG (biopsy). <h3>Results</h3> Thirty cases of ACG were identified by compatible biopsy that had an ultrasound study of AT in the emergency department. On the other hand, 47 ultrasound AT studies were identified in patients who were not finally diagnosed with ACG. All included records were distributed between 2012 and 2016. Ultrasound exploration of positive AT was understood as that with 2 or more branches with positive halo sign (Sifuentes, Ann Rheum Dis 2013-eular- OP0208). Tables 2x2 were elaborated to establish the results of the validation test with three and four ACG classification criteria. One patient was identified with the combination of criteria: cephalea + VSG &gt; 50mm/h + Alt. of the exploration of the AT and 4 with cephalea + Age &gt; 50 years + Alt. of the exploration of the AT. Of these patients, only one had ultrasound study of AT so they were excluded from the study. With 4 criteria + halo sign (+), an S of 93.3% and NPV of 93.3% was achieved; with 3 criteria + halo sign (+) an S of 83.3% and NPV of 93.7% was achieved. The attached table shows all the results of the validation test. <h3>Conclusion</h3> Although the application of the GCA classification criteria has insufficient specificity and low positive predictive value, when adding the ultrasound study of TA, specificity exceeds 93% and PPV exceeds 93% when combined with 4 criteria and 83% when combined with 3 criteria. Although our results should be supported by a larger sample size, our findings assume that the routine use of this technique would contribute to improving the diagnostic accuracy of this disease and our ability to initiate treatment in a more timely manner. <h3><b>Disclosure of Interests</b></h3> None declared