Two cases with SLE and MCTD developed after a long period of chronic arthritis that was initially diagnosed as JRA

: In order to discuss the diversity of clinical features and the difficulty in diagnosis of children with juvenile rheumatoid arthritis (JRA), we present two cases who have documented the development of systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) after a long period of disease characterized only by arthritis that was initially diagnosed as JRA. The first case was a girl diagnosed for her arthritic joints as polyarticular JRA at 15 years of age. At onset, she had Raynaud phenomenon but autoantibodies such as anti-nuclear antibody (ANA), anti-DNA antibody, and rheumatoid factor were negative. Five years after onset, she became ANA positive and 3 years later she became pregnant. During her pregnancy, she became positive for anti-DNA antibody without any signs of nephritis. One month after the delivery, however, she developed butterfly rash, carditis, nephritis, and was diagnosed as SLE. No destructive changes were observed in her joints though arthritis continued for 8 years form onset to pregnancy. The second case was a 3 years old girl who was diagnosed as polyarticular JRA. Treatment by aspirin induced complate remission after one year from the onset. However, 10 years after that remission, she developed Raynaud phenomenon and arthralgia in her knees and hip joints. Her laboratory findings showed hypergammaglobulinemia, positive ANA, positive anti-DNA antibody, positive anti-RNP antibody. She was eventually diagnosed as MCTD when she was found to have polymyositis by EMG and serum CK. In the present paper, two cases imply the difficulty in diagnosing JRA and diversity of rheumatic diseases such as JRA, SLE and MCTD. Closer and longer period of observation is essential for the JRA patients with nondestructive arthritis.