COPD: exacerbation.

A renewed interest in the clinical and pathogenic aspects of COPD exacerbation is timely in view of national and global COPD initiatives. The three big problems regarding COPD continue to be the following: prevention of the disease; slowing progression of the disease once diagnosis has been established; and prevention and more effective treatment of the so-called exacerbation. The following assessment will raise more questions than answers and will review some of the past and current concepts and contexts.