Pathophysiology
Clinical meaning
In pediatric patients, CF manifests early with meconium ileus in neonates (10-15% of CF infants), failure to thrive due to pancreatic insufficiency, and recurrent respiratory infections. The immature immune system combined with impaired mucociliary clearance makes infants and children particularly vulnerable to Staphylococcus aureus and Haemophilus influenzae initially, with Pseudomonas aeruginosa colonization typically occurring by school age.