Myositis in primary Sj(o)gren's syndrome

Abstract

This study was to identify the clinical features of myositis complicated with primary Sj(o)gren's syndrome (pSS). A total of 202 patients with pSS were investigated. Myositis was diagnosed according to the clinical findings, muscle enzyme levels, electromyographic results, and muscle biopsy, and compared with 15 polymyositis (PM) patients. Myositis was identified in 4 of 202 pSS patients (2.0%). They developed myositis 5 to 20 years after the onset of SS. Two patients showed no myalgia and muscular weakness. Creative kinase (CK) was increased from 480 to 2702 IU/L. Anti-Jo-1 antibody was negative. All patients responded well to prednisone and had a median serum CK decrease by 48.9%. No patients had myositis recurrence. Compared with the PM group, the percentage of myalgia, peak of CK, descending rate of CK, and positive rate of anti-Jo-1 antibody were all significantly different. Myositis with Sj(o)gren's syndrome is not common, show relatively moderate symptoms, and respond well to prednisone. Key words: Sj(o)gren's syndrome; Myositis