"Nonobstructive" emphysema of the lung

An unusual case of smoking-related centrilobular emphysema with normal spirometry.
A 64-year-old man presented with severe dyspnoea and respiratory failure. Pulmonary
function and mechanics were normal except for a marked reduction in diffusing capacity of
the lung.
High-resolution CT scan showed diffuse centrilobular emphysema also involving lower
lobes. Pulmonary embolism, cardiac or pulmonary shunt and immunopathologically based
vasculitis were excluded. Pulmonary pressure was at the upper limit of normality but
within few months he developed a severe pulmonary hypertension.
Although spirometry is the only physiologic measure recommended by the updated Global
Initiative for Chronic Obstructive Lung Disease guidelines for confirming the diagnosis it
should be recognized that diffuse emphysema may occur with only abnormalities in gas
exchange without airflow obstruction. The identification of different phenotypes within
COPD is important for understanding disease heterogeneity and progression.