Chronic obstructive lung disease: from structure to pathology

Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by progressive and irreversible airway obstruction and ubiquitous chronic inflammation in the lung. It is the end result of accumulated damage to many parts of the lung by many types of noxious agents, a destructive exhaustion of the lung reserve. Recent increases in the incidence of COPD have occurred mainly in older age groups, in non-smokers, and in females. Pathologically, COPD is characterized by chronic inflammation which perpetuates and accumulates locally. Discrete areas interact with each other, in the locus resistentia minoris (LRM), the sites of weak resistance of the lung, suggesting that insidious destruction with exhaustion of pulmonary reserves is still the main culprit of COPD. Traditional treatments of COPD are useful in symptomatic control but do not prevent progression of the disease. Prevention is still the best way to manage COPD. New pharmaceutical agents and bioengineered products using molecular or genetic techniques to block inflammatory mediators or their receptors may contain the inflammatory and noxious agents in the LRM and prevent their propagation. Methodologies involving structural approaches, such as devices to estimate the status of airways and associated vessels and the remaining lung reserve, creation of collateral or bypass ventilation pathways, and reduction of volume of over-inflated areas may be effective. The balance between exposure and clearance, injury and repair, ultimately decides how quickly the great reserves of the lung are depleted.