ITE Pulmonology 2 — Questions and Answers
Question 1: A 58-year-old male with COPD has a PaCO2 of 68 mmHg at baseline. He is started on supplemental oxygen and his PaCO2 rises to 82 mmHg with worsening somnolence. Which mechanism best explains this hypercapnia?
- Increased dead space ventilation
- Haldane effect releasing CO2 from hemoglobin (Correct answer)
- Suppression of hypoxic drive reducing minute ventilation
- Worsening V/Q mismatch from oxygen-induced pulmonary vasoconstriction
Correct answer: Haldane effect releasing CO2 from hemoglobin
The Haldane effect causes oxyhemoglobin to release CO2 more readily, and V/Q mismatch worsening also contributes, but the primary mechanism in COPD oxygen-induced hypercapnia is the Haldane effect displacing CO2 from hemoglobin.
Question 2: A 45-year-old woman presents with progressive dyspnea and PFTs showing FVC 62%, FEV1 68%, FEV1/FVC 88%, and DLCO 48%. CT chest shows bilateral ground-glass opacities with subpleural honeycombing. What is the most likely diagnosis?
- Nonspecific interstitial pneumonia (NSIP)
- Idiopathic pulmonary fibrosis (IPF) (Correct answer)
- Cryptogenic organizing pneumonia (COP)
- Hypersensitivity pneumonitis
Correct answer: Idiopathic pulmonary fibrosis (IPF)
Subpleural honeycombing on HRCT with a restrictive pattern and reduced DLCO in an older patient is the classic presentation of IPF with a UIP pattern.
Question 3: A patient with sarcoidosis has bilateral hilar lymphadenopathy on CXR but is asymptomatic. Spirometry is normal. What is the most appropriate management?
- Start prednisone 40 mg/day
- Start methotrexate
- Observation and monitoring (Correct answer)
- Perform surgical lung biopsy
Correct answer: Observation and monitoring
Stage I sarcoidosis (bilateral hilar adenopathy without parenchymal infiltrates) in asymptomatic patients frequently remits spontaneously and does not require treatment.
Question 4: A 32-year-old nonsmoking female develops sudden onset pleuritic chest pain and dyspnea. CXR shows a 30% right-sided pneumothorax. She has no prior history. What is the most appropriate next step?
- Needle aspiration (Correct answer)
- Small-bore chest tube placement
- Observation with 100% oxygen
- Video-assisted thoracoscopic surgery (VATS)
Correct answer: Needle aspiration
For a first episode of primary spontaneous pneumothorax >20%, needle aspiration is the recommended first-line intervention per BTS guidelines.
Question 5: A 65-year-old male with a 40 pack-year history presents with hemoptysis and a 3 cm spiculated right upper lobe mass on CT. PET scan shows uptake in the mass and ipsilateral mediastinal nodes. What TNM stage does mediastinal nodal involvement represent?
- N1
- N2 (Correct answer)
- N3
- M1a
Correct answer: N2
Ipsilateral mediastinal or subcarinal lymph node involvement is classified as N2 disease in the TNM staging system for lung cancer.
Question 6: A 28-year-old with HIV (CD4 count 45 cells/µL) presents with fever, dry cough, and progressive dyspnea over 3 weeks. LDH is markedly elevated. CXR shows bilateral interstitial infiltrates. What is the first-line treatment?
- Trimethoprim-sulfamethoxazole + prednisone (Correct answer)
- Azithromycin + ethambutol
- Fluconazole
- Ganciclovir
Correct answer: Trimethoprim-sulfamethoxazole + prednisone
PCP pneumonia in HIV patients with moderate-to-severe disease (PaO2 <70 mmHg or A-a gradient >35) is treated with TMP-SMX plus adjunctive corticosteroids.
Question 7: A 55-year-old male with obesity (BMI 38) reports excessive daytime sleepiness and witnessed apneas. Polysomnography shows AHI of 42 events/hour with oxygen desaturations to 78%. What is the most appropriate initial treatment?
- Mandibular advancement device
- Positional therapy
- CPAP therapy (Correct answer)
- Uvulopalatopharyngoplasty (UPPP)
Correct answer: CPAP therapy
CPAP is the first-line treatment for moderate-to-severe obstructive sleep apnea (AHI ≥15 events/hour) and is superior to other modalities for symptom relief.
ITE Pulmonology 2
A 58-year-old male with COPD has a PaCO2 of 68 mmHg at baseline.
He is started on supplemental oxygen and his PaCO2 rises to 82 mmHg with worsening somnolence.
Which mechanism best explains this hypercapnia?