This case involves a middle-aged woman who was diagnosed and treated for tuberculosis. The patient went back to her pulmonologist for a followup appointment after completing the medication treatment and was told by her pulmonologist that she was recovered. However, the patient continued to be symptomatic and expressed concern about her symptoms. The pulmonologist assured her that she was fine. Within the month, the patient began feeling weaker and experienced difficulty walking and sleeping. The patient then began coughing up blood and losing weight. She returned to the pulmonologist, who decided to do a lung bacterial culture. The culture came back positive for mycobacterium avium complex (MAC). He was referred to an infectious disease physician and treatment for the MAC commenced. In spite of multiple treatments, the patient ultimately required oxygen full time.
Question(s) For Expert Witness
- 1. Please describe your experience diagnosing and treating MAC?
- 2. What sort of symptoms would make you consider MAC?
- 3. What is the standard work up and diagnosis criteria for MAC?
Expert Witness Response E-001199
I have treated many cases of MAC and have several patients under my clinical care currently that are on active MAC regimens. I am currently a co-investigator on a clinical trial testing a nebulized antibiotic for MAC at my university. The classic symptoms of pulmonary MAC infection are cough, weight loss, fatigue, and intermittent low-grade fever. The standard workup includes chest CT and multiple sputum samples for AFB smear and culture. Alternatively, one bronchoscopic specimen can be used if pt is unable to produce sputum. Classic cases of pulmonary MAC involve nodular and bronchiectactic lung disease, often progressing to more cystic and cavitary disease. The presence of typical lung changes with repeated isolation of MAC from sputum samples is classic. Therapy is prolonged, often problematic, and not infrequently complicated by the emergence of drug resistance to the macrolide or rifamycin derivative (less commonly the ethambutol). In those cases, we’ll send for drug resistance testing — although it is expensive.