Physiopathology of Exacerbation of Chronic Obstructive Pulmonary Disease.

Acute exacerbations of chronic obstructive pulmonary disease (ECOPD) represent crucial events in the natural history of the disease. These are mainly characterized by abrupt worsening of respiratory symptoms, that is, dyspnea, cough, and sputum production. Defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as acute symptom deterioration requiring additional therapy, ECOPD markedly worsens lung function and has strong clinical outcomes for any patient involved. Pathobiology is multidimensional, arising from inflammatory, mechanical, and cardiovascular perturbations that are linked to each other and are likely to generate a self-reinforcing cycle of respiratory derangement and/or failure. Indeed, lung inflammation and injuries intensify airflow limitation, which in turn promotes air trapping and dynamic hyperinflation, increases elastic loads, and predisposes to respiratory muscle dysfunction. The resulting alterations of the blood gases may lead to even severe respiratory system failure and to an increased risk of death.