Internal Medicine Exam Pulmonary Disease Essentials 4 — Questions and Answers
Question 1: A 45-year-old HIV-positive patient (CD4 count 80 cells/μL) presents with dry cough, fever, and diffuse bilateral ground-glass opacities. LDH is elevated. What is the most likely diagnosis?
- Bacterial pneumonia (Streptococcus pneumoniae)
- Pneumocystis jirovecii pneumonia (PCP) (Correct answer)
- Cryptococcal pneumonia
- Mycobacterium avium complex
Correct answer: Pneumocystis jirovecii pneumonia (PCP)
PCP is the most common AIDS-defining opportunistic lung infection, typically presenting with subacute dry cough, hypoxia, elevated LDH, and bilateral ground-glass opacities when CD4 < 200.
Question 2: Which spirometry pattern is consistent with a diagnosis of restrictive lung disease?
- FEV1/FVC < 0.70 with normal TLC
- FEV1/FVC ≥ 0.70 with reduced TLC (Correct answer)
- FEV1/FVC < 0.70 with increased TLC and air trapping
- FEV1/FVC ≥ 0.70 with normal TLC and reduced DLCO
Correct answer: FEV1/FVC ≥ 0.70 with reduced TLC
Restrictive lung disease is defined by reduced TLC (< 80% predicted) with a preserved or elevated FEV1/FVC ratio on spirometry.
Question 3: A 60-year-old man presents with obstructive sleep apnea confirmed on polysomnography with AHI of 32 events/hour and lowest SpO2 of 81%. He declines CPAP. What is the next best alternative therapy?
- Positional therapy alone
- Mandibular advancement device (Correct answer)
- Protriptyline nightly
- Supplemental nocturnal oxygen
Correct answer: Mandibular advancement device
Mandibular advancement devices are the preferred alternative to CPAP in moderate-to-severe OSA when CPAP is declined, repositioning the jaw to enlarge the upper airway.
Question 4: A patient with ARDS is on mechanical ventilation. Current settings: TV 8 mL/kg IBW, PEEP 8 cmH2O, FiO2 0.70, plateau pressure 34 cmH2O. Which change should be made immediately?
- Increase FiO2 to 1.0
- Reduce tidal volume to 6 mL/kg IBW (Correct answer)
- Decrease PEEP to 5 cmH2O
- Switch to pressure-control ventilation
Correct answer: Reduce tidal volume to 6 mL/kg IBW
The ARDSNet protocol mandates tidal volumes of 4-6 mL/kg IBW to limit ventilator-induced lung injury; plateau pressure > 30 cmH2O indicates overdistension requiring TV reduction.
Question 5: Which finding on Light's criteria indicates an exudative pleural effusion?
- Pleural fluid protein/serum protein ratio < 0.5
- Pleural fluid LDH/serum LDH ratio > 0.6 (Correct answer)
- Pleural fluid LDH < 2/3 upper limit of normal serum LDH
- Pleural fluid cholesterol < 45 mg/dL
Correct answer: Pleural fluid LDH/serum LDH ratio > 0.6
Light's criteria identify exudate if any one of three criteria is met: pleural/serum protein > 0.5, pleural/serum LDH > 0.6, or pleural LDH > 2/3 upper limit of normal serum LDH.
Question 6: A 55-year-old male ex-smoker (40 pack-years, quit 3 years ago) presents for lung cancer screening. Which imaging modality is recommended by USPSTF guidelines?
- Annual chest X-ray
- Low-dose CT (LDCT) annually (Correct answer)
- PET-CT every 2 years
- Sputum cytology combined with annual chest X-ray
Correct answer: Low-dose CT (LDCT) annually
USPSTF recommends annual LDCT screening for adults aged 50-80 with ≥ 20 pack-year history who currently smoke or quit within the past 15 years.
Question 7: A patient with bronchiectasis has repeated Pseudomonas aeruginosa infections. Which maintenance therapy is most appropriate to reduce exacerbation frequency?
- Daily oral amoxicillin-clavulanate
- Inhaled tobramycin or aztreonam alternating monthly (Correct answer)
- Monthly IV ceftazidime
- Daily trimethoprim-sulfamethoxazole
Correct answer: Inhaled tobramycin or aztreonam alternating monthly
Inhaled anti-pseudomonal antibiotics (tobramycin or aztreonam on alternating month schedules) suppress Pseudomonas colonization and reduce exacerbations in bronchiectasis.
Internal Medicine Exam Pulmonary Disease Essentials 4
A 45-year-old HIV-positive patient (CD4 count 80 cells/μL) presents with dry cough, fever, and diffuse bilateral ground-glass opacities.
LDH is elevated.
What is the most likely diagnosis?