Early chronic obstructive pulmonary disease: Beyond spirometry

Figure 1 Disease progression in chronic obstructive pulmonary disease. Genetic factors interact with exposures, predominantly cigarette smoke, but also others such as biomass smoke to cause cellular changes in the lung, including inflammation. These cause changes that can be detected first at a pathological level - for instance subtle small airway changes or early emphysema. Later these are seen radiologically, and finally physiologically. Symptoms may occur after physiological changes occur, or in some cases earlier in the disease process. Indeed by the time symptoms develop it is likely the disease is established and may no longer be true “early” chronic obstructive pulmonary disease.