Physician Assistant Pulmonary System Disorders 2

Question 1

A 55-year-old smoker presents with progressive dyspnea, barrel chest, and decreased breath sounds bilaterally. Spirometry shows FEV1/FVC of 0.58. Which pathophysiologic mechanism best explains the air trapping?

Accepted Answer

Loss of elastic recoil causing dynamic airway collapse

Answer

In emphysema, destruction of alveolar walls reduces elastic recoil, causing small airways to collapse during exhalation and trapping air distally.

Question 2

A patient with a known pulmonary embolism develops sudden worsening of hypoxemia despite anticoagulation. Which mechanism most directly causes hypoxemia in acute PE?

Accepted Answer

Ventilation-perfusion mismatch with increased dead space

Answer

PE creates high V/Q areas (dead space) where ventilation occurs without perfusion, and can also cause atelectasis leading to low V/Q areas, both worsening oxygenation.

Question 3

A 30-year-old with cystic fibrosis presents with increased sputum production and worsening FEV1. Sputum culture grows Pseudomonas aeruginosa. Which antibiotic combination is most appropriate for an acute exacerbation?

Accepted Answer

Piperacillin-tazobactam and tobramycin

Answer

Anti-pseudomonal beta-lactam plus an aminoglycoside provides synergistic coverage against Pseudomonas in CF exacerbations and helps prevent resistance.

Question 4

A 68-year-old with a 6 cm solitary pulmonary nodule has a PET scan showing high SUV uptake. CT-guided biopsy reveals adenocarcinoma. Which staging workup is MOST critical before surgical planning?

Accepted Answer

Brain MRI and mediastinoscopy

Answer

Brain MRI detects occult CNS metastases and mediastinoscopy evaluates mediastinal lymph node involvement, both critical for determining resectability in NSCLC.

Question 5

A patient with sarcoidosis has bilateral hilar lymphadenopathy on CXR and an ACE level of 85 U/L. Serum calcium is 11.4 mg/dL. What is the mechanism of hypercalcemia in this condition?

Accepted Answer

1-alpha hydroxylation of vitamin D by activated macrophages in granulomas

Answer

Activated macrophages within sarcoid granulomas express 1-alpha-hydroxylase, converting 25-OH vitamin D to calcitriol, which increases intestinal calcium absorption.

Physician Assistant Practice Test

Physician Assistant Practice Test

Physician Assistant Pulmonary System Disorders 2