Women who are elderly white, thin and non-smoking seem to be more vulnerable to lung infections with Mycobacterium avium complex and few other non-tuberculous mycobacteria (NTM). It has been assumed that such disease in these women is mostly related to suppression of their cough.

A study has hypothesized that patients with pulmonary NTM (pNTM) infections might have altered cough physiology as compared to the unaffected control participants. Cough was induced by a small dose of capsaicin to assess the cough reflex in pNTM subjects. Almost 8 elderly white women with stable chronic pNTM infections and 6 unaffected age-matched control participants were enrolled. No significant difference was seen between groups in capsaicin-elicited cough motor response, cough frequency or airflow pattern. The urge-to-cough (UTC) score at the lowest capsaicin concentration was suggestively lower in pNTM as compared to the control participants (P < 0.05).

No significant differences were seen in the UTC score between pNTM and control participants at >50 μM capsaicin. The results suggested the lower UTC sensitivity to the lowest capsaicin concentration in pNTM as compared to the control participants. This means that the pNTM participants do not sense a UTC when the stimulus is comparatively small.

The study has evaluated the cough sensitivity and cough motor response in patients with nontuberculous mycobacteria (NTM) infection. These study findings are important to recognize the pathophysiological mechanisms that resulted in NTM disease in elderly white women and the syndrome that was developing in elderly white female NTM patients.

Source: Tsai HW, Fennelly K, Wheeler-Hegland K, et al. Cough physiology in elderly women with nontuberculous mycobacterial lung infections. J Appl Physiol (1985). 2017 May 1;122(5):1262-1266. doi: 10.1152/japplphysiol.00939.2016. Epub 2017 Mar 2.