The Clinical Study On Inflammatory Myopathies

Lee, Sang Heon; Lim, Hyo Young; Yang, Hyung In; Park, Sung Hwan; Cho, Chul Soo; Kim, Ho Youn

Abstract

OBJECTIVE
To determine possible similarities and differences in clinical and laboratory features and prognosis between patients with inflammatory myopathies diagnosed at Kangnam St. Mary's hospital and other reported series.
METHODS
Medical records of 52 patients diagnosed as inflammatory myopathies by Bohan and Peter criteria who were admitted to Kangnam St. Mary's hospital between January 1989 and August 1994, were reviewed. The patients were further classified into 5 groups proposed by Bohan and Peter ; group I primary polymyositis(PM), group II primary dermatomyositis(DM), group III polymyositis/dermatomyositis(PM/DM) with neoplasia, group IV juvenile PM/DM, group V PM/DM associated with connective tissue disease.
RESULTS
1) There were 52 PM/DM cases with mean age at diagnosis of 34. 4 ranging from 6 to 67 years, and significantly more females(male:female = 9:43). 2) Of 52 patients, group II was the most frequent group(36.5%), and the next were as follows ; group I 28.8%, group V 25%, group IV 5.7%, group 3.8%. Systemic lupus erythematosus(SLE) was the commonest connective tissue disease, and malignancy was associated in 2 cases including breast cancer and small cell carcinoma of lung. 3) At presentation, 86.5% had proximal muscle weakness, 61.5% had arthralgia/arthritis and 44. 2% had Raynaud phenomenon. 4) The elevated serum LDH, aldolase and creatine kinase were found in 84. 6%, 84. 1%o, 71.2% of the patients respectively. Positive electromyography and muscle biopsy consistent with inflammatory myopathy were also found in 91.4%, 88.8% respectively. 5) Positive antinuclear antibody, rheumatoid factor, anti-Ro, anti-nRNP were found in 59.6%, 17.3%, 16.7%, 8.3% of patients respectively, mainly in group V. Anti-Jo-1 antibody was present in 25.8% of patients tested(8/31), including group II 4 cases, group V 3 cases and group I I case. 6) All 8 patients with anti-Jo-1 antibody had interstitial lung disease(ILD) and Raynaud phenomenon with statistical significance, compared with those without anti-Jo-1 antibody(P<0.01). 7) Among the 43 patients in whom follow up was available, 10 patients died(mortality rate 23.2%). The main cause of death were infection(4 cases), and respiratory muscle weakness, respiratory failure due to ILD, malignancy 2 cases respectively.
CONCLUSION
The results of the study demonstrated that clinical expression of PM/DM were similar to previously reported series except relatively high frequency of primary dermatomyositis in this study. Anti-Jo-1 antibody was main autoantibody in inflammatory myopathies, which was associated with extramuscular manifestations, such as ILD and Raynaud's phnomenon.