Diagnosis and treatment of pulmonary nontuberculous mycobacteriosis

Abstract

Pulmonary non-tuberculous mycobacteriosis in Japan occurs more than about 5,000 cases annually. Among them, about 70% are occupied by Mycobacterium avium complex (MAC) infection. Considering the frequency and the difficulty of treatment, we discuss mainly on pulmonary MAC infection on this report. At National Tokyo hospital, secondary MAC infection after tuberculosis sequelae were 46.5% out of 170 pulmonary MAC cases since 1969 to 1985, but it decreased to 19.4% out of 268 cases since 1986 to 2000. In this same period, a type of MAC infection like middle lobe syndrome without recognizing preceding pulmonary disease, increased to 69.8% out of all pulmonary MAC cases (Fig. 1). Recently, this type of pulmonary MAC infection, which consists with scattered nodular lesion and local bronchiectasis in middle lobe or lingula, attracts attention. Why is there much frequency in women? Why does it originate from middle lobe or lingula? Although, it shows a characteristic X-ray pattern, ant it is still an interesting problem, the origin of the disease cannot be clarified. First diagnostic standard of nontuberculous mycobacteriosis in Japan was submitted in 1967, and the current diagnostic standard was made in 1985, through several times improvements. These contents are almost similar to that of American diagnostic standard in 1997, but the new revision that reflected chest CT findings and bronchoscopic sampling etc, is pressed now. In the treatment, INH or PZA, which is a key drug in tuberculous chemotherapy, is not a key drug in MAC chemotherapy. MAC chemotherapy is multidrugs combination chemotherapy including EB, CAM, RFP, and aminoglycosides. However, it is difficult to achieve complete regression with current drugs combinations, and an early surgical resection is the most effective in case of localized MAC lesion. We propose a guidance of treatment selection with age and disease severity (Table). Fig. 2 shows survival curves of 104 cases pulmonary MAC infection at National Tokyo Hospital.