268. IMPACT OF MUSCULOSKELETAL ULTRASOUND TO EVALUATE SUSPECTED INFLAMMATORY ARTHRITIS IN THE CITY HOSPITAL RHEUMATOLOGY DEPARTMENT: A SERVICE EVALUATION

Abstract

Background: Over the last 2 decades, musculoskeletal ultrasound (MSUS) has become a widely used diagnostic tool in rheumatologic practice because it is easily accessible, cost-effective, non-invasive, and well tolerated by patients. Increasing amounts of literature have confirmed that MSUS is superior to clinical examination in detecting synovitis. It is particularly useful in the evaluation of patients with suspected early inflammatory arthritis. The identification of these patients may allow clinicians to initiate early aggressive therapies in order to minimize joint destruction and functional loss. However, definitive guidelines on the use of this technology in clinical practice have yet to be devised. Methods: We carried out a service evaluation of all patients in our department who had undergone Ultrasound Hands, Wrists and/or Feet in the 12 month period from May 2015 to May 2016. We collected demographic data as well as information on indication, serology, inflammatory markers, correlation between ultrasound findings and clinical examination and whether the ultrasound result influenced the resulting management of the patient. Patients were categorized into two groups those with and those without synovitis detected by ultrasound. Their characteristics were compared using chi-square and Students' tests, to try and determine which variables were significantly correlated with presence of synovitis. Results: We identified 148 patients. 43% (63/148) had an established diagnosis of an inflammatory arthritis. The indication in 97% (144/148) of patients was to determine the presence of subclinical joint inflammation. 25% (37/148) of our patients had some degree of synovitis on ultrasound. 54% (20/37) had immunosuppression commenced or escalated. 55% (11/20) of these patients had an established diagnosis of an inflammatory arthritis. Ultrasound of the feet was requested in 11% (17/148) and one individual had immunosuppression commenced as a result of synovitis in the feet. Of patients with negative ultrasounds, 10% (11/111) had immunosuppression commenced or escalated, while 12% (13/111) had other interventions such as physiotherapy or pain clinic referral. Overall, 41% (60/148) of patients had changes to their management following their ultrasound result. Patients with ultrasound demonstrated synovitis had shorter mean symptom duration, longer mean duration of morning stiffness and were more frequently CCP Positive. Only the difference in frequency of CCP Positivity reached statistical significance. Conclusion: Results from musculoskeletal ultrasound frequently influenced clinical decisions. However, clinicians were sceptical about the clinical significance of mild joint inflammation on ultrasound imaging, especially when patients had concomitant osteoarthritis. The majority of patients with mild synovitis or no synovitis did not have immunosuppression escalated. Ultrasound was slightly more useful in those with an established diagnosis of inflammatory arthritis while ultrasound scanning of feet was of doubtful utility. Only CCP Positivity was significantly correlated with synovitis on ultrasound.