UK guidelines on the lung condition non-tuberculous mycobacterial pulmonary disease (NTM-PD) aim to standardise the definition “so we are all talking about the same condition”.

Speaking to the limbic Dr Charles Haworth, guideline co-author and director of the Cambridge Centre for Lung Infection said that while a definition of NTM-PD was agreed in the US in 2007, in the UK “no-one has been sure which definition to use”.

The British Thoracic Society guidelines committee agreed to adopt the definition from the American Thoracic Society/Infectious Diseases Society of America. This, Dr Haworth hopes, will facilitate research on prevalence and risk factors for the condition, and standardise diagnosis.

“One of the key elements is how you differentiate a positive [mycobacterium] culture, which can happen in people without particular problems, versus a positive culture in the context of inflammatory lung disease,” he said in an interview.

Since publication of the previous BTS guideline in 2000, technological advances have allowed better identification of NTM species in the laboratory, as well as improved ability to assess the impact of infection through imaging.

The diagnostic work-up in the new guideline includes analysis of three sputum samples and a high-resolution CT chest scan, before treatment is considered.

Dr Haworth says the guideline should also standardise treatment, through updated algorithms and a comprehensive drug monograph.

Many of the 150 species of NTM are multi-drug resistant, making choice of treatment regime challenging. Toxicity and drug interactions are a particular problem.

“At the moment, people are often treating these infections in a variety of ways, so it’s very difficult to work out what’s working and what isn’t,” says Dr Haworth.

The guideline committee used the best clinical evidence available, backed by clinical expertise where evidence was lacking. “We have tried to simplify the treatment regimens as much as possible, and standardise them to improve clinical outcomes and reduce side effects.”

You can access the full guidelines here.