A 9-year-old boy with neonatal meconium ileus presents with recurrent pneumonia, chronic productive cough, steatorrhea, and poor weight gain. Vital signs: HR 102/min, RR 24/min, SpO2 94% on room air. Chest X-ray shows bronchiectasis with bronchial wall thickening. Sweat chloride test is markedly elevated at 85 mEq/L. He denies hemoptysis. He currently takes pancreatic enzymes and albuterol as needed. Which pathophysiologic mechanism best explains his progressive pulmonary disease?
- A)IgA deficiency causing recurrent mucosal infection only
- B)Type I pneumocyte destruction causing diffuse alveolar collapse
- C)Thick dehydrated secretions causing airway obstruction and recurrent infectionGABARITO
- D)Defective dynein arms causing impaired ciliary motility
- E)Loss of dystrophin causing weak respiratory muscles
Explicação
Cystic fibrosis results from defective CFTR chloride transport, leading to dehydrated, thick secretions in the airways. Mucus plugging predisposes to recurrent infection, chronic inflammation, and bronchiectasis. The associated pancreatic insufficiency and mec... Ver explicação completa e trilha adaptativa →