Study objectives: To review the experience of an
outpatient pulmonary clinic with Mycobacterium
avium-intracellulare (MAI) pulmonary disease in the
HIV-negative population without preexisting lung disease.
Design: Retrospective clinical series.
Setting: University medical center.
Patients: The clinic charts of all patients who fulfilled
the current American Thoracic Society criteria for MAI pulmonary
infection and who had no preexisting lung disease or immunosuppression
Measurements and results: Of 31
patients identified, 94% were female, 90% were white, and the median
age at diagnosis was 63 years. The median time interval from symptom
onset to diagnosis was 10 months. Bronchiectasis or small nodules
without predilection for any lobe was found in 93%. Bronchoscopy or
open lung biopsy for diagnosis was required in 45% because of
nondiagnostic sputum cultures. At ≥ 12 months, 50% failed therapy,
86% continued to be symptomatic, and 58% did not tolerate their
initial multidrug regimen.
Conclusions: These results
emphasize the observed chronic nature of MAI pulmonary disease in this
population, both before diagnosis and despite therapy. The sensitivity
of sputum culture in this population is low, so an aggressive
diagnostic approach, including bronchoscopy, should be considered if
sputum cultures are negative. Current treatments are suboptimal because
of poor drug tolerance and significant failure rates. Last, the
preponderance of disease in older white women argues for a genetic or
acquired immune deficiency to explain disease
Abbreviations: AFB = acid-fast bacilli;
ATS = American Thoracic Society; HRCT = high-resolution CT;
MAI = Mycobacterium avium-intracellulare;
MTB = Mycobacterium tuberculosis