Today I’m laid up with a viral illness so I decided to write a brief blog post for clinicians with some tips for treating mycobacterial diseases (tuberculosis, MAC, and other NTMs).
- For NTM, get familiar with the ATS/IDSA guidelines.
- Drug susceptibility testing is key. For tuberculosis that is done at the State public health lab. For NTM, it is either done at National Jewish in Denver or at the University of Texas (Tyler). They will send you your MICs which will guide your treatment.
- We think drug levels are important, although some people don’t agree (the Uptodate article by Dr David Griffith states, “There is minimal clinical evidence that monitoring drug levels and optimizing dosage affects the therapeutic outcome.”) After patients have been on TB or MAC treatment for a few weeks we send their blood to Dr. Charles Peloquin’s infectious diseases pharmacokinetics laboratory at the University of Florida. It takes a bit of work because patients have to time the blood draw correctly and the sample gets sent out, but the results return quickly and help us understand if our patients are receiving therapeutic levels of drug. If levels are low, the dose may need to be increased.
- This is a very interesting issue because even in the USA I suspect the minority of NTM/TB patients are getting drug levels. How often are they under-dosed? What about MDR/XDR-TB patients globally? Are we driving more MDR/XDR resistance globally by under-dosing? How important is it, really, to measure drug levels?
- Treatment requires an interdisciplinary team: laboratory, ID, pulmonary, radiology, thoracic surgery, nursing, and your administrative assistant who helps coordinate/schedule sputum collection. Make especially good friends with your thoracic radiologist. You will spend lots of time with them going over CT scans. Is there more bronchiectasis on today’s CT scan compared to the previous one?
- Give the patient written instructions on how to start their treatment. We often do a stepwise treatment invitation and it is a bit complicated. Put those written instructions in the chart as well.
- Is the patient having an active flare of MAC or is s/he at his/her baseline?
- Airway clearance is important for MAC. For instance, work with your pulmonologist to make sure they are getting appropriate treatment, i.e. acapella valve, chest PT, etc. Try to prevent aspiration and bacterial superinfection.
- Don’t forget about fungus. Aspergillus can live inside old cavities.
- Flu vaccine, pneumococcal vaccination, smoking cessation, and ART if they are HIV positive
- We lack data about some of the most important questions in the treatment of MAC. For instance, patients may continue to regrow MAC despite treatment and the decision to re-initiate is not clearcut. More research is needed.
- PS- Dr. Dan Bourque adds that MAC may be hiding in your showerhead.