Physician Assistant Pulmonary System Disorders 3 — Questions and Answers
Question 1: A 52-year-old with obstructive sleep apnea refuses CPAP. Which consequence of untreated OSA poses the greatest cardiovascular risk?
- Nocturnal hypoventilation causing CO2 retention
- Repetitive hypoxemia and sympathetic surges causing systemic hypertension (Correct answer)
- Reduced cardiac output from decreased preload during apneas
- Peripheral chemoreceptor desensitization to hypoxia
Correct answer: Repetitive hypoxemia and sympathetic surges causing systemic hypertension
Repetitive hypoxic episodes and arousal-associated sympathetic activation cause sustained systemic hypertension, which is the primary cardiovascular complication of OSA.
Question 2: A 40-year-old woman presents with exertional dyspnea and a mean pulmonary artery pressure of 30 mmHg on right heart catheterization. She has no left heart disease or lung disease. Which treatment is first-line for Group 1 pulmonary arterial hypertension?
- High-dose calcium channel blockers for all patients
- Phosphodiesterase-5 inhibitors or endothelin receptor antagonists (Correct answer)
- Long-term anticoagulation with warfarin
- Supplemental oxygen therapy alone
Correct answer: Phosphodiesterase-5 inhibitors or endothelin receptor antagonists
PDE-5 inhibitors (sildenafil) or endothelin receptor antagonists (bosentan, ambrisentan) are first-line for Group 1 PAH in patients without vasoreactivity on testing.
Question 3: A 35-year-old non-smoker presents with lower lobe-predominant emphysema and recurrent liver disease. Which deficiency should be suspected?
- Alpha-1 antitrypsin deficiency (Correct answer)
- IgA deficiency
- Cystic fibrosis transmembrane conductance regulator mutation
- Primary ciliary dyskinesia
Correct answer: Alpha-1 antitrypsin deficiency
Alpha-1 antitrypsin deficiency causes panacinar emphysema predominantly in the lower lobes and can cause liver disease from misfolded protein accumulation in hepatocytes.
Question 4: A mechanically ventilated ARDS patient has plateau pressure of 32 cmH2O and PEEP of 10 cmH2O. Driving pressure is 22 cmH2O. Which ventilator adjustment best reduces ventilator-induced lung injury?
- Increase FiO2 to reduce PEEP requirement
- Reduce tidal volume to achieve driving pressure ≤15 cmH2O (Correct answer)
- Increase respiratory rate to normalize PaCO2
- Switch to pressure-controlled ventilation mode
Correct answer: Reduce tidal volume to achieve driving pressure ≤15 cmH2O
Driving pressure (plateau - PEEP) >15 cmH2O is associated with increased ARDS mortality; reducing tidal volume to lower driving pressure reduces stress on remaining functional lung units.
Question 5: A 60-year-old with COPD and FEV1 of 35% predicted has multiple hospitalizations yearly. Which long-acting bronchodilator combination has the strongest evidence for reducing exacerbations?
- Short-acting beta-agonist plus short-acting muscarinic antagonist
- Long-acting beta-agonist plus inhaled corticosteroid plus long-acting muscarinic antagonist (triple therapy) (Correct answer)
- Inhaled corticosteroid alone
- Long-acting beta-agonist alone
Correct answer: Long-acting beta-agonist plus inhaled corticosteroid plus long-acting muscarinic antagonist (triple therapy)
Triple therapy (LABA + LAMA + ICS) reduces exacerbation rates more than dual therapy in severe COPD patients with frequent exacerbations, per the IMPACT trial.
Question 6: A 25-year-old with asthma is awakened 4 nights per week by wheezing and uses rescue albuterol daily. Spirometry shows FEV1 of 75% predicted with 15% bronchodilator response. How is this asthma classified?
- Mild intermittent asthma
- Mild persistent asthma
- Moderate persistent asthma (Correct answer)
- Severe persistent asthma
Correct answer: Moderate persistent asthma
Daily symptoms, nighttime awakenings more than once per week, and FEV1 60-80% predicted classify asthma as moderate persistent, requiring step 3-4 therapy.
Question 7: A 70-year-old post-lobectomy patient develops fever, purulent sputum, and a new air-fluid level on CXR 10 days postoperatively. What is the most likely diagnosis?
- Pulmonary embolism with infarction
- Lung abscess (Correct answer)
- Bronchopleural fistula with empyema
- Hospital-acquired pneumonia
Correct answer: Lung abscess
An air-fluid level within a cavitary lesion with fever and purulent sputum after thoracic surgery indicates a lung abscess, often from anaerobic or gram-negative organisms.
Physician Assistant Pulmonary System Disorders 3
A 52-year-old with obstructive sleep apnea refuses CPAP.
Which consequence of untreated OSA poses the greatest cardiovascular risk?