Ventilatory defects in atypical mycobacteriosis. A comparison study with tuberculosis

Two hundred thirty-two patients infected with Mycobacterium kansasii and 120 patients infected with M. intracellulare who were admitted to the East Texas Chest Hospital between 1965 and 1974 were individually matched according to age (+/- 5 years), sex, and extent of disease with an equal number of patients infected with M. tuberculosis. The ventilatory function in these patients was compared. The frequency of obstructive ventilatory defect, defined as forced expiratory volume in 1 sec less than 70 per cent of forced vital capacity, was greater among M. kansasii patients (68.9 per cent of 232) than among M. tuberculosis patients less than 80 per cent of predicted, was greater among M. intracellulare patients (68.3 per cent of 120) than among M. tuberculosis patients (57.5 per cent of 120). Above age 40, obstructive ventilatory defects tended to be more common in M. kansasii patients, whereas restricted ventilatory defects tended to be more common in M. intracellulare patients when compared with the same age group of M. tuberculosis patients. As expected, ventilatory function values among the M. tuberculosis groups decreased as extent of disease increased. In contrast, among the M. kansasii and M. intracellulare groups, these values were poorly related to the extent of disease; values were relatively low even with minimal extent of disease. It is suggested that the increased ventilatory defects among the M. kansasii and M. intracellulare patients could be accounted for by coexistent lung disease.