PANCE Pulmonary System 2 — Questions and Answers
Question 1: A 55-year-old smoker presents with progressive dyspnea and a barrel chest. Spirometry shows FEV1/FVC ratio of 0.60. Which pathophysiologic mechanism best explains his air trapping?
- Loss of elastic recoil causing dynamic airway collapse (Correct answer)
- Bronchial smooth muscle hypertrophy
- Mucus gland hyperplasia obstructing large airways
- Alveolar wall thickening reducing diffusion capacity
Correct answer: Loss of elastic recoil causing dynamic airway collapse
In emphysema, destruction of alveolar walls reduces elastic recoil, causing dynamic small airway collapse during expiration and air trapping.
Question 2: A 30-year-old woman with known asthma presents to the ED with severe bronchospasm unresponsive to two doses of albuterol. Which medication is most appropriate next?
- Oral prednisone 40 mg
- IV magnesium sulfate (Correct answer)
- Inhaled ipratropium bromide
- IV aminophylline
Correct answer: IV magnesium sulfate
IV magnesium sulfate relaxes bronchial smooth muscle and is indicated for severe acute asthma refractory to initial bronchodilator therapy.
Question 3: A patient with community-acquired pneumonia has a parapneumonic effusion. Thoracentesis reveals pH 7.15, glucose 45 mg/dL, and LDH 1,200 U/L. What is the next best step?
- Continue antibiotics and repeat thoracentesis in 48 hours
- Chest tube drainage (Correct answer)
- Thoracoscopic debridement
- Intrapleural fibrinolytics only
Correct answer: Chest tube drainage
A pH <7.20, glucose <60 mg/dL, and elevated LDH indicate a complicated parapneumonic effusion requiring chest tube drainage.
Question 4: Which finding on chest X-ray is most characteristic of a tension pneumothorax?
- Contralateral tracheal deviation with ipsilateral lung collapse (Correct answer)
- Bilateral diffuse infiltrates
- Unilateral pleural effusion without mediastinal shift
- Ipsilateral tracheal deviation with complete opacification
Correct answer: Contralateral tracheal deviation with ipsilateral lung collapse
Tension pneumothorax causes mediastinal shift away from the affected side due to positive pressure buildup, displacing the trachea contralaterally.
Question 5: A 45-year-old with silicosis develops a new cavitary upper lobe lesion. Which organism is most likely responsible?
- Streptococcus pneumoniae
- Mycobacterium tuberculosis (Correct answer)
- Pseudomonas aeruginosa
- Aspergillus fumigatus
Correct answer: Mycobacterium tuberculosis
Silicosis dramatically increases susceptibility to tuberculosis, which preferentially causes upper lobe cavitary lesions.
Question 6: A patient with COPD has a resting PaO2 of 54 mmHg and cor pulmonale. What is the minimum daily duration of supplemental oxygen required to improve mortality?
- 8 hours
- 12 hours
- 15 hours (Correct answer)
- 24 hours
Correct answer: 15 hours
The NOTT trial established that at least 15 hours per day of supplemental oxygen reduces mortality in hypoxemic COPD patients.
Question 7: A 60-year-old presents with recurrent hemoptysis, and CT shows a central endobronchial lesion. Biopsy reveals squamous cell carcinoma. Which paraneoplastic syndrome is most associated with this tumor type?
- SIADH causing hyponatremia
- Hypercalcemia due to PTHrP secretion (Correct answer)
- Cushing syndrome from ectopic ACTH
- Eaton-Lambert syndrome
Correct answer: Hypercalcemia due to PTHrP secretion
Squamous cell carcinoma of the lung is the most common cause of hypercalcemia of malignancy via PTHrP secretion.
PANCE Pulmonary System 2
A 55-year-old smoker presents with progressive dyspnea and a barrel chest.
Spirometry shows FEV1/FVC ratio of 0.60.
Which pathophysiologic mechanism best explains his air trapping?