A 12-year-old girl has a 7-year history of coughing and wheezing and repeated attacks of difficulty breathing. The attacks are particularly common in spring. During an episode of acute respiratory difficulty, a physical examination shows that she is afebrile. Her lungs are hyperresonant on percussion, and a chest radiograph shows increased lucency of all lung fields. Laboratory tests show an elevated serum IgE level and peripheral blood eosinophilia. A sputum sample examined microscopically also has increased numbers of eosinophils. Which of the following histologic features is most likely to characterize the lung in her condition?

Correct Answer: D

Rationale: Airway remodeling with smooth muscle hyperplasia (D) defines atopic asthma in this girl (Page 28, Ans: E). Spring attacks, high IgE, and eosinophils signal type I hypersensitivity TH2-driven inflammation . Repeated episodes thicken bronchial walls (50% muscle increase), causing wheezing. Bronchiole dilation (A) is emphysema. Bronchial destruction (B) is bronchiectasis. Edema (C) fits ARDS. D's chronic change unlike A's irreversible loss explains reversible obstruction, per document.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: A stab wound causing pneumothorax collapses the lung (intrapleural pressure equals atmospheric, 0 mmHg) and expands the chest wall (outward recoil). Lung collapse (D) loses negative pressure (-5 cm H2O at FRC). Chest expansion (not A or C) follows elastic recoil. FRC fixation (B) doesn't occur air entry disrupts balance. D's dynamics unlike A's dual expansion match pneumothorax physiology (Q58).