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Abstract
Chronic obstructive pulmonary disease (COPD) exacerbations are important events that contribute to worsening health status, disease progression, and mortality. They are mainly triggered by respiratory viruses (especially rhinovirus, the cause of the common cold), but airway bacteria are also involved in their pathogenesis. Exacerbations are associated with both airway and systemic inflammation and, this is mainly neutrophilic in origin. Some patients are especially prone to develop exacerbations, and these have been identified as a high-risk group with increased airway inflammation and greater disease progression. Management of acute exacerbations involves therapy with oral corticosteroids and/or antibiotics, and new therapies are needed. A number of interventions may prevent exacerbations, including vaccination, long-acting bronchodilators, antiinflammatory agents, and long-term antibiotic therapy. Understanding of the pathophysiological mechanisms of COPD exacerbations is important to develop novel therapies.
Exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the natural history of the disease as they impact on health status, disease progression, and survival (1, 2). Exacerbations are associated with increased airway inflammation, increased mucous production, and often marked air trapping that contributes to the increased dyspnea observed. COPD exacerbations are complex symptomatic events that are mainly triggered by respiratory viral infections, although bacteria also may initiate and amplify these events, together with environmental factors such as pollution and ambient temperature (1). The most common virus isolated is human rhinovirus, which can be detected for up to a week after exacerbation onset (3). When associated with viral infections, exacerbations are often more severe and longer, with more hospital admissions, as seen in winter months. A study from the London COPD cohort shows that exacerbations may have two basic patterns, either rapid onset and recovery or a slower onset and recovery, and it is the latter that is more likely to be associated with viral triggers (4). COPD exacerbations are also associated with increased cardiovascular risk and subclinical increases of cardiac enzymes, especially in the presence of airway viral or bacterial infection at exacerbation (5).
Most exacerbations recover between 7 to 10 days, but some events may last longer; at 8 weeks after the onset of an exacerbation, approximately 20% of exacerbations have not recovered to their stable preexacerbation levels (6). A recent study has shown that where exacerbations do...