16th February 2025

A 48-year-old woman is referred for pulmonary function tests due to progressive cough, breathlessness and reduced exercise tolerance.

A 48-year-old woman is referred for pulmonary function tests due to progressive cough, breathlessness and reduced exercise tolerance. Her background included rheumatoid arthritis, for which she takes methotrexate. She has a 30-pack-year smoking history. The results are as follows:

Baseline spirometry: FEV1 1.9 L (58% predicted), FVC 4 L (95% predicted), FEV1/FVC ratio 47%

Spirometry following 5 mg nebulised salbutamol: FEV1 2.2 L (67% predicted), FVC 4.2 L (100% predicted), FEV1/FVC ratio 52%

What is the most likely cause of her breathlessness?

Select the SINGLE most appropriate option from the list below. Select ONE option only.