An Asymptomatic Patient with Severe Airway Obstruction

A 44-year-old man was referred by his occupational physician because of a progressive decline in forced expiratory volume in 1 s (FEV 1 ) detected at an annual medical check-up. The patient was a former smoker, with a 25 pack-year smoking history. He quit smoking 2 years ago. He was known to have an IgE-mediated allergy to grass and tree pollen with an associated oral allergy syndrome to stone fruits. He denied any respiratory symptoms and had an excellent exercise capacity (swimming 2 km twice a week). Clinical examination was non-remarkable. Spirometry was performed. FEV 1 /forced vital capacity of 34% and FEV 1 of 1.67 liters or 48% of predicted confirmed severe airway obstruction. Peak expiratory flow was 5.13 l/s or 59% of predicted. There was no significant reversibility after bronchodilation with salbutamol. Static lung volumes and diffusion capacity for carbon monoxide were within the normal range. The flow-volume (FV) loop is shown in figure 1 .