Pulmonary function testing in cystic fibrosis typically shows what pattern?

Pulmonary function testing in cystic fibrosis typically shows what pattern?

• A. Restrictive, reversible
• B. Obstructive, irreversible
• C. Normal
• D. Pure restrictive

Answer: (B)

Cystic fibrosis causes thick mucus and chronic airway inflammation that narrows the airways, especially during expiration, leading to an obstructive pattern on lung function testing. The hallmark is reduced expiratory flow, specifically a lower FEV1 and a reduced FEV1/FVC ratio. As the disease progresses, air trapping can cause hyperinflation, so total lung capacity may be normal or increased. Unlike some obstructive conditions, the obstruction in CF is largely fixed by structural changes, so reversibility with bronchodilators is limited or minimal. So, the typical PFT pattern is obstructive and largely irreversible.

Cystic fibrosis causes thick mucus and chronic airway inflammation that narrows the airways, especially during expiration, leading to an obstructive pattern on lung function testing. The hallmark is reduced expiratory flow, specifically a lower FEV1 and a reduced FEV1/FVC ratio. As the disease progresses, air trapping can cause hyperinflation, so total lung capacity may be normal or increased. Unlike some obstructive conditions, the obstruction in CF is largely fixed by structural changes, so reversibility with bronchodilators is limited or minimal. So, the typical PFT pattern is obstructive and largely irreversible.