Non-tuberculous mycobacterial (NTMB) pulmonary infection is a chronic pulmonary infection with variable presentation clinically and on imaging. While these organisms are ubiquitous and exposure is common. However, infection rates after exposure are low. Most cases of chronic NTMB pulmonary infection occur in patients over the age of 50 with underlying pulmonary disease, such as COPD, or patients with immunologic disease. The most common organisms are M avium-intracellulare and M kansasii. Classic infection pattern is indistinguishable from post-primary tuberculosis, with upper lobe cavitary nodules commonly seen. This pattern is more common in elderly men. The non-classic infection is typically seen in elderly women with chronic cough, sometimes called the "Lady Windermere Syndrome." The non-classic infection pattern typically shows bronchiectasis, centrilobular nodules and tree-in-bud opacities, with predilection for the lingula and right middle lobe. Cavitation is not seen in the non-classic presentation.
This case presents a classic pattern of NTMB infection, proven to be M avium intracellulare. While the classic form is more common in men with COPD, this patient's underlying smoking history and COPD may have predisposed her to the classic presentation rather than the non-classic form, which is more common in females.