Descriptors of dyspnea in obstructive lung diseases

In obstructive lung diseases such as asthma and COPD dyspnea is a common respiratory symptom with different characteristics given the different pathogenic mechanisms: in COPD initially it can occur during exertion but then it increases progressively along with the airflow obstruction, whereas in asthma it occurs episodically and is caused by transient bronchoconstriction. The language of dyspnea includes a large range of clinical descriptors which have been evaluated for their correlation (of one or several descriptors) with underlying physiologic/physiopathologic mechanisms. These studies were done in asthma rather than in COPD, and dyspnea descriptors were found to be useful in identifying patients with life-threatening asthma. However further studies are needed to further explore such descriptors and their clinical utility. This review discusses dyspnea mechanisms in various obstructive lung disease subsets as well as the descriptors of dyspnea and their utility in clinical practice.