THU0568 CLINICAL CHARACTERISTICS OF SEVEN RELAPSING POLYCHONDRITIS CASES MISDIAGNOSED AS ARTHRITIS
Authors: Xiaoyu Cao, Jiu-Liang Zhao, Dong Xu, Yong Hou, Xiaofeng Zeng
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Relapsing polychondritis (RPC) is a rare autoimmune disease. It mainly affects the tissue abundant of cartilage, such as ear, nose, and tracheoles. The multiple systems including eye, joint, mucocutaneous, and kidney could be involved<sup>1</sup>. As the presentation of arthritis was nonspecific and could appear in several connective tissue diseases, it was easily misdiagnosed. The delay in establishing the diagnosis of RPC was common. A survey from the United Kingdom found a median length of 1.9 years from the first disease attack to diagnosis<sup>2</sup>. One recent research reported 64% of RPC patients had a diagnostic delay with more than five years<sup>3</sup>. <h3>Objectives</h3> We made a retrospective study to explore distinct characteristics of relapsing polychondritis with arthritis as the first attack. By comprehending the nature of disease fully, misdiagnosis at the early phase of illness could be avoided. <h3>Methods</h3> The clinical features and prognosis of 7 RPC patients in Peking Union Medical College Hospital between October 2012 and October 2018, presenting as arthritis at onset, were retrospectively analyzed. <h3>Results</h3> There were five female patients. The female to male ratio of the case series was 5:2. The age of 7 patients was 43.43±9.86 years. The number of affected joints was 20.14±10.92. The joint involvement was most common in the bilateral proximal interphalangeal joints (PIPs) and interphalangeal joints of the thumb. Recurrent arthritis occurred in 5 patients. There was no accompanying enthesitis. The specific serum indexes of RA, such as rheumatoid factor (RF), anti-cyclic citrullinated peptide (CCP) antibody, were negative. There were three patients administered with conventional synthetic disease modifying anti-rheumatic drugs firstly, and they did not respond well. The median delay time from onset to diagnosis of RPC was ten month (Figure 1). The deformity and destruction of the joint were not observed in all patients, by clinical and radiological assessment. The average duration from arthritis to the occurrence of other involved system was 8.3 months. Four patients were misdiagnosed as rheumatoid arthritis at first. One patient was considered as ankylosing spondylitis at first. Two patients were diagnosed as arthritis at the beginning. As regards to treatment, glucocorticoids (GCs), cyclophosphamide and mycophenolate mofetil were used. Two patient was complicated with palmoplantar pustulosis and Kikuchi-Fujimoto disease. During follow up, myelodysplastic syndrome occurred in one patient. After following up for 35.43±30.92 months, all patients survived and were not with the recurrence of arthritis. <h3>Conclusion</h3> RPC patients with arthritis onset were characteristic of middle-aged women and symmetric multiple joint involvements. The RF and anti-CCP antibody were negative. The arthritis was recurrent and not erosive. The interphalangeal joints of the thumb and PIPs were the most frequently involved joints. In clinical practice, physicians should be alert to the possibility of RPC, when encountered the patients with abovementioned arthritis. The inquiry about manifestations of other system involvement in RPC and a regular follow-up was warranted. After the combined therapy of GCs and immunosuppressants, all patients had a favorable prognosis. <h3>References</h3> [1] Chopra R, Chaudhary N, Kay J. Relapsing polychondritis. Rheumatic diseases clinics of North America2013; 39(2): 263-76. [2] Hazra N, Dregan A, Charlton J, Gulliford MC, D'Cruz DP. Incidence and mortality of relapsing polychondritis in the UK: a population-based cohort study. Rheumatology2015; 54(12): 2181-7. [3] Ferrada MA, Grayson PC, Banerjee S, et al. Patient Perception of Disease-Related Symptoms and Complications in Relapsing Polychondritis. Arthritis care &amp; research2018; 70(8): 1124-31. <h3>Acknowledgement</h3> none <h3>Disclosure of Interests</h3> None declared