P178 Use of a musculoskeletal ultrasound (MSK US) protocol for the initial assessment of patients with suspected psoriatic arthritis (PsA): results of a service improvement project

Abstract

Background/Aims MSK US changes in PsA are well recognised. We initially conducted a literature review to summarise the research in MSK US use in PsA, and its value in assessing its diagnosis in patients with skin psoriasis (PsO). This informed the development of a standard US protocol for screening patients with PsO and arthralgia at their first presentation to rheumatology clinic as part of a service improvement project. We aimed to assess the potential role of US in the assessment and triage of PsA referrals. Methods Consecutive patients referred with possible PsA across Newcastle and Northumbria Trusts were booked into dedicated appointments. All had personal history of PsO without previous PsA diagnosis. Patients were reviewed independently by 2 clinicians: initially for protocolised ultrasound scan and separately for clinical assessment, see Figure 1. Ultrasonographic entheseal grading was used, as specified by GRAPPA. Both clinicians documented the likelihood of PsA diagnosis. Subsequently, clinical judgements were reviewed in the context of the US findings. Results 41 patients were scanned (Figure 1); 14 male and 27 female. Mean age 49.9 years, PASI score 3.0, ultrasound duration 26.7 minutes. In the majority, clinical and ultrasound outcomes matched. 30/41 patients showed no concern of PsA after dual ultrasound and clinical assessment and were discharged. On clinical examination, 15/41 had entheseal tenderness on palpation. On US, only 2 of these had consistent ultrasound changes. 6 patients were diagnosed with PsA, and in each clinical and ultrasound outcomes matched. Of these 6, 4 had knee synovitis, and 3 had ankle involvement (2 with effusion with synovial hypertrophy; 1 tibialis posterior tenosynovitis). Conclusion Screening tests for PsA such as PEST can result in high numbers of referrals with low yield of PsA diagnosis. It can be difficult to exclude PsA clinically in those with PsO and arthralgia, especially when entheseal or joint tenderness is present. We have demonstrated that a protocolised MSK US scan can help to differentiate patients with active inflammation who need prompt assessment and treatment, and those who do not and can be safely discharged. This has the potential to streamline referral routes for these patients. Disclosure K. Khokhar: Honoraria; KK has received conference sponsorship from UCB.. Grants/research support; This work formed part of a post-CCT Rheumatology Ultrasound Fellowship hosted by Newcastle and Northumbria Foundation Trusts. Novartis funded the salary and training costs of the Fellow (KK). I. Atchia: Consultancies; IA has received consultancy fees/advisory board from Abbvie. Honoraria; IA has received conference sponsorship from UCB, Eli Lilly and Novartis. B. Thompson: Honoraria; BT has received honoraria/travel support from Abbvie, Chugai, Janssen, Lilly, Novartis and UCB.