Introduction
Between 1995 and 2012, the incidence of non-tuberculous mycobacterial (NTM) culture positive isolates increased eightfold in England, Wales and Northern Ireland from 0.9 per 100 000 population in 1995 to 7.6 per 100 000 in 2012. This incidence is now similar to that of tuberculosis (TB), cases of which are now declining.1–3 Around 200 species of Mycobacteria have been identified over a spectrum of pathogenicity, although most do not cause disease in humans.4–6 While the rise in incidence may be driven by factors such as improved awareness and better diagnostic tools, it is likely to be a true representation of the increased frequency with which these robust environmental organisms are now isolated.
The majority of clinical NTM cases manifest as pulmonary disease (non-tuberculous mycobacterial pulmonary disease (NTM-PD)), with a smaller number affecting extrapulmonary sites such as the skin and soft tissue.7 8 Mycobacterium avium complex (MAC, including M. avium, M. intracellulare and M. chimaera), and M. abscessus are associated with around 90% of the total number of reported cases of NTM-PD.9–11
Uncertainties around the management of NTM-PD include its epidemiology, diagnosis, treatment and prevention. These are addressed to some extent in the 2017 British Thoracic Society (BTS) guidelines12; however, variations in care remain for UK patients with NTM-PD. Paediatric NTM-PD is rare outside of the cystic fibrosis (CF) population, and hence the evidence base on which to guide management decisions is even smaller than for adult NTM-PD.13 An in-depth discussion of paediatric NTM-PD is beyond the scope of this article, although we recommend that such cases are managed in consultation with specialist centres. Using a clinical case of NTM-PD, we will review the current status and challenges of patient management and consider practical ways in which NTM services may be optimised in the future. While the focus of this article is the UK, many issues are relevant to the global management of NTM-PD.
Case: A 67-year-old slim-build woman with a history of smoking-associated chronic obstructive pulmonary disease (COPD) presents to her community COPD clinic with a productive cough and unintentional weight loss. Her COPD is managed with inhaled corticosteroids in combination with long-acting bronchodilators, and she has recently experienced recurrent respiratory infections, despite repeated courses of antibiotics. She also has ongoing gastro-oesophageal reflux disease (GORD). Chest X-rays carried out by the COPD team look generally similar to previous imaging, though occasional nodularity that appeared to resolve on repeat imaging was noted.