Background and objective: Pulmonary Mycobacterium avium complex (MAC) disease is the most common pulmonary non-tuberculous mycobacteriosis (NTM). The clinical and radiological findings were similar to those of pulmonary tuberculosis, both of which are characterized by upper lobe cavities. On the other hand, the presence of middle and lower field lesions with centrilobular nodules and bronchiectasis has been noted. We analyzed the clinical feature of these two radiologically different types and identified their prognostic factors.
Methods: The clinical, laboratory and radiological findings of 273 cases of MAC disease, newly diagnosed during the recent 7 years periods, were investigated. They were radiologically classified into cavitary (Cav) and nodular bronchiectasis (NB) types at the time of diagnosis. The findings of 44 fatal cases were compared with those of the newly diagnosed cases.
Results: A prominent increase in the number of cases was recently found only in females. Low body mass index (BMI) and moderately reduced serum albumin were found at the time of first hospital visit in both newly diagnosed and fatal cases. In the latter, peripheral blood lymphocyte count was slightly decreased, and tuberculin skin test was negative in 57.7% of the cases. Radiologically, Cav type was prevalent in males and NB type in females in the newly diagnosed cases, while in the fatal cases Cav type was frequently found in both males and females. The two radiological patterns did not change during the entire disease course.
Conclusion: Cav type in females was one of the pathogenetic factors. Deterioration of cell-mediated immunity may underlie MAC disease.