A 60-year old woman was referred to the tuberculosis (TB) out-patient clinic for Mycobacterium avium (MAC) pulmonary disease after having received 1st line antituberculosis treatment (isoniazid, rifampicin, ethambutol, pyrazinamide) for one month. The initial clinical diagnosis was pulmonary TB, based on patient's symptoms, consisting of fever, productive cough and weight loss for the last 2 months, along with compatible to tuberculosis chest x-ray and computed tomography (CT) scan. The CT scan had revealed 3 cavities and tree-in-bud appearance of the right upper lobe (Fig. 1). Acid-fast smears from sputum and bronchial lavage were negative, however cultures from the lavage revealed the presence of MAC.
The patient had a decade-long history of bronchiectasis with her respiratory tract being chronically colonized with P. aeruginosa. She reported infectious exacerbations during the last 10 years, which were mostly treated with macrolides or quinolones. Due to increase in the frequency of the exacerbations to 3-4 per year in the last two years, the patient was on maintenance treatment with azithromycin 250 mg three times per week for the last six months, as suggested by her treating physician.
On examination, after one month of anti-TB treatment, the patient was found to have gained weight and she reported as being afebrile for the last 2 weeks and without cough. Despite this initial response to treatment, positive culture results from one bronchial washing sample, along with the patient's symptoms and radiological findings, fullfilled ATS criteria for MAC pulmonary disease diagnosis. Her treatment was modified to rifampicin, ethambutol, azithromycin and amikacin. One month later, resistance to macrolides was detected, so azithromycin was discontinued and isoniazid and moxifloxacin were added to the regimen. The patient received treatment for 24 months (amikacin for eight months) and showed a significant clinical and radiological improvement. The patient was unable to produce sputum so microbiological follow up could not be performed. Her CT scan at the end of treatment was also significantly improved (Fig. 2). Due to the persisting presence of a cavity in the right upper lobe at the end of the treatment, the option of surgical resection was proposed but the patient refused. At present, six months after the completion of her treatment, she remains clinically stable and does not report any bronchiectasis-related infectious exacerbation.