Clinical study on development of nontuberculous mycobacterial lung disease

DEVELOPEMENT OF MAC LUNG DISEASE: An increase of nodular bronchiectatic type of MAC lung disease becomes a problem among respiratory physician today. The reason is still unknown, but it seems to be globally recognized that this type of MAC disease is developing particularly in middle-aged woman. Some papers mentioned the existence of such type of MAC lung disease already early in the 70s, in Japan. Yamamoto described that 17 cases of middle lobe type lung disease out of 154 non-photochoromogen cases, and 76.5% were female, in 1970. Shimoide also pointed such type of 39 cases out of 240 MAC lung disease and 84.6% were female, in 1980. Prince reported MAC lung disease seen in old and middle age female of 21 cases including lethality example of 4 cases without a precedent disease in 1989. After his report, the international consensus of this peculiar type of MAC lung disease seems to be spread. In 1989, we compared 72 cases of nodular bronchiectatic type of MAC lung disease and 56 cases of diffuse panbronchiolitis (DPB) that was a most typical chronic airway disease at that time in Japan. The average age of disease onset of DPB group was 37.0 +/- 16.3 years old and that of MAC group was 54.5 +/- 16.3 years old. The percentage of female was 32% in DPB group and 87.5% in MAC group. It was highly possible that two groups belong different parent population. We could grasp that nodular bronchiectatic type of MAC lung disease patients is a unique group. We observed the serial films of 21 cases of nodular bronchiectatic MAC lung disease, and divide the progression of the disease to sequential 7 steps as Fig. 1. Small nodules progress to cavities in mean about 10 years. However, why is MAC which is opportunistic pathogen with weak virulence, able to form a lesion at unimpaired lung parenchyma? Is there really normal site? Why dose it start from lingula? Why is MAC seen a lot in woman? While it is extremely pathognomonic clinical picture, and, is an extremely interesting problem, most are still unidentified. STUDY OF MAC LUNG DISEASE TREATMENT: It was known that Mycobacterium kansasii lung disease is healed with a chemotherapy like analog of anti-tuberculosis chemotherapy, already in those days. However, the results of MAC lung disease chemotherapy were extremely poor. We tried to express a physicians experience quantitatively as follows, in 1987. The results of 8 weeks sputum culture on Ogawa egg medium were converted semi-quantitatively to CFU numbers based on "Japanese standard guideline of Mycobacterium tuberculosis inspection". We exhibit the ratio of post-treatment consecutive 6 months culture yield to pre-treatment culture yield as response rate, about 110 pulmonary MAC cases. Through this study, we clarify the followings. The results of chemotherapy do not correlate susceptibility test for Mycobacterium tuberculosis. Multidrug regimen is more useful. Small extent of lesion is more responsive. Combination with aminoglycoside chemotherapy is more effective. These conclusions were almost same as the ATS guideline of 1990. New drugs such as, new macrolides and new quinolones appeared for pulmonary MAC treatment through the feedback from systemic MAC complicated AIDS treatments from the latter half of 90's. We measured the sensitive strain ratio at 2 mcg/ml of OFLX, CPFX, LVFX about 990 clinical isolates and could expect availability for M. kansasii or M. fortuitum, but these new quinolones are not enough effective for MAC. Also we examined MIC for various antimycobacterial agent by 50 MAC clinical isolates, and we could expect a certain availability of SPFX, GFLX, CPFX, CAM for MAC. The availability of clarithromycin (CAM) has been established through many randomized clinical trials for disseminated MAC complicated AIDS, but for pulmonary MAC, complete cure is still difficult if we use CAM including regimen. We performed surgical treatment for relatively young patients with localized lesions. We carry out the adaptation reference such as Table, now. The localization of the lesions become a problem at surgical resection. Through the study of our 55 surgical treatment cases, 8 cases (67%) relapsed out of 12 cases which had destructive airway structure in unresected lung field. On the other, only 1 case relapsed (10%) relapsed out of 10 cases without airway destruction in unresected lung. Therefore, even if there is a little dispersal focus without airway destruction in the other pulmonary lobe except purpose focus of resection, it seems that control is possible by post operational chemotherapy. LONG SURVIVAL: As overall consequence, we calculate the survival curves of 201 pulmonary MAC patients visited Tokyo National Hospital from 1953. The survival medium value was 7332 days. The prognosis of nodular bronchiectatic type was better than that of post-tuberculosis type. Extent of disease measured by chest X-ray examination at the time of first visit may be a most affecting factor to the survival rate.