E013 A service evaluation of a diagnostic ultrasound service for the assessment of giant cell arteritis

Abstract

Background/Aims Early recognition and treatment are key in the management of Giant Cell Arteritis (GCA) to prevent visual loss. Temporal artery ultrasound (TAU) is increasingly used as the first line investigation for GCA. Classic GCA findings include the halo sign, slope sign and compression sign. We established a TAU service in 2023: the aim of this service evaluation (e2024-108) is to assess the effectiveness of the service, including wait time and outcomes. Methods: Methods Case-record review of all patients who had a TAU between 05/04/2023 and 14/08/2024. Information was collected on demographics, clinical features, management and scan findings. Results were collated and correlation calculated between likelihood of positive/negative result, duration of glucocorticoid course and inflammatory marker status. Results 133 people had first TAU scans (2 patients had repeat scans). 35 (26%) were positive, and 98 (74%) negative. The median (range) age was 70 (42-89) years. Patients with positive scans were older: median 76 (57-88) years compared with 67 (42-89) years. Of those with positive TAU 51% had raised inflammatory markers, with higher mean inflammatory markers: mean (range) CRP 46.9 (0-284), ESR 20.5 (2-112) versus mean CRP 12.9 (0-119.2), ESR 13.3 (2-92) with negative TAU. 45% of those with negative scans had raised inflammatory markers. Delay between referral and scan was similar with median (range) of 2 (0-15) days for negative scans vs 2 (0-27) for positive scans. 77% of positive scans were performed within 3 days of referral, 97% within 7 days compared with 59% of negative scans within 3 days of referral, and 94% within 7 days. 81% of negative scans were performed within 7 days of steroid commencement and 51% within 3 days. 63% of positive scans were performed within 7 days of steroid commencement and 40% within 3 days. 61% of patients were taking concurrent steroids with mean duration 5.46 days. Glucocorticoid duration median (range) prior to TAU was 3 (0-27 days [positive TAU]) vs 2 (0-92 days [negative TAU]). Correlation coefficient between duration of glucocorticoid treatment and scan result was -0.03, showing negligible correlation. For those testing negative, 20% were treated clinically despite scan result, and 52% stopped or tapered steroids immediately. 46% were prescribed daily 60mg prednisolone with a positive scan and 40% in negative. 40% were prescribed 60mg prednisolone with a negative scan and 48% prescribed 40mg. Conclusion This service evaluation demonstrates provision of rapid TAU service with 95% of all scans performed within 7 days of referral. No correlation was seen between duration of glucocorticoids and scan findings. More data is needed to explore the relationship between steroid dose, duration, USS findings and to assess how long positive findings remain on TAU. Disclosure S.P. Shastri: None. A. Longmead: None. C. Oldham: None. A. Hall: None. A. Menon: None. S.L. Hider: None.