A New Era for the Early and Non-Invasive Diagnosis of Giant Cell Arteritis: The Use of Fast-Track Ultrasound in Clinical Practice

Background: The assessment of giant cell arteritis (GCA) in fast-track assessment clinics (FTA) including the use of ultrasound (US) is becoming the preferred practice in specialized centers. Methods: Patients with suspected GCA referred to the FTA of the Rheumatology Department, University of Pavia, Italy, between 2016 and 2021 were included to analyze the clinical and US findings. Results: A total of 553 US examinations were performed on 347 patients. A total of 246 were female (71%), and the mean age was 73 ± 12. Of these, 287 US on newly referred patients led to a confirmed diagnosis of GCA in 111 (39%). The sensitivity of US was 81.98% (95% CI 73.55–88.63%), and the specificity 99.43% (95% CI 96.88–99.99%). Only 4 patients required temporal artery biopsy. The most specific symptoms to inform the pre-test probability of GCA and differentiate from patients with other conditions were: jaw or tongue claudication, scalp tenderness, and bilateral visual loss. Headache was not reported in 33% of patients. Systemic symptoms were significantly more frequent in GCA (42.3%), together with combinations of cranial, systemic, and/or polymyalgia rheumatica symptoms. Out of 88 patients, there were 52% with a confirmed relapse. Of these, 67% had a positive US. Conclusion: The use of FTA in clinical practice ensures an early diagnosis, avoiding invasive procedures for the patient. Our data support the increasingly recognized adjunctive role of US in the monitoring of GCA.