Which best describes the pathophysiology of CF in the lungs?

Which best describes the pathophysiology of CF in the lungs?

• A. Thick, viscous mucus causing obstructive lung disease
• B. Increased mucociliary clearance
• C. Decreased mucus production
• D. Hyperhydration of airways

Answer: (A)

In cystic fibrosis the lungs are dominated by thick, sticky mucus that plugs and obstructs the airways. This results from a CFTR gene mutation that causes defective chloride transport and increased sodium absorption across the airway surface epithelium, which draws water out of the surface liquid. The net effect is dehydration of the airway surface and production of viscid mucus that is hard to clear. That mucus plugging impairs mucociliary clearance, promotes bacterial colonization, and drives chronic neutrophilic inflammation. Over time this leads to recurrent infections, airway damage, and an obstructive pattern on lung function testing. Mucociliary clearance is not increased in CF; it is impaired. Mucus production is not decreased; it is increased but becomes abnormally thick and sticky. Hyperhydration of the airways would counteract the dehydration seen in CF, which is not the case.

In cystic fibrosis the lungs are dominated by thick, sticky mucus that plugs and obstructs the airways. This results from a CFTR gene mutation that causes defective chloride transport and increased sodium absorption across the airway surface epithelium, which draws water out of the surface liquid. The net effect is dehydration of the airway surface and production of viscid mucus that is hard to clear.

That mucus plugging impairs mucociliary clearance, promotes bacterial colonization, and drives chronic neutrophilic inflammation. Over time this leads to recurrent infections, airway damage, and an obstructive pattern on lung function testing.

Mucociliary clearance is not increased in CF; it is impaired. Mucus production is not decreased; it is increased but becomes abnormally thick and sticky. Hyperhydration of the airways would counteract the dehydration seen in CF, which is not the case.