title: Clinical characteristics of Mycobacterium tuberculosis infection among rheumatoid arthritis patients.
abstract: To evaluate the clinical characteristics of Mycobacterium tuberculosis infection in rheumatoid arthritis (RA) patients, we examined the clinical manifestations and radiography/computed tomography (CT) findings in RA patients with tuberculosis (RA+/TB+). A total of 1121 tuberculosis patients were admitted to our hospital from 1995 to 2003, with the RA patients among them comprising 1.8% (20 cases; 9 men and 11 women). This is approximately three times as high as the prevalence of RA in the entire population in Japan. In addition, the RA+/TB+ patients were older and had a longer history of RA than the 140 outpatients in our RA clinic who did not have tuberculosis (RA+/TB-). Half of the RA+/TB+ patients had no symptoms (e.g., cough, sputum, pyrexia), and their tuberculosis was detected accidentally by radiography/CT. The positive rates of the bacilli in the smear and culture of the sputum from the RA+/TB+ patients were lower than those from 143 patients randomly selected from among 1091 tuberculosis patients without any collagen disease including RA (RA-/TB+). The RA+/TB+ patients had a higher incidence of extrapulmonary tuberculosis (30%), including four cases (20%) of miliary tuberculosis, an incidence seven times higher than among the general population of tuberculosis patients. Among 14 cases of pulmonary tuberculosis patients with RA, bilateral lesions and non-cavitary lesions were found in 71.4% and 64.3%, respectively, which tended to be a higher incidence than in the RA-/TB+ patients. The mortality rate and sputum conversion time of the RA+/TB+ patients were no different from those of the RA-/TB+ patients. The prevalence of tuberculosis in RA patients is expected to increase after introduction of anti-cytokine therapy in Japan, and careful observation should be done to avoid this complication in RA patients.
authors.affiliation: Department of Rheumatology, National Minami-Okayama Hospital, 4066 Hayashima, Hayashima-cho, Tsukubo-gun, Okayama 701-0304, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Yoshinaga
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kanamori
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ota
authors.forename: Tomoko
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kagawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamamura