Pulmonology Flashcards

A 58-year-old man with systemic sclerosis presents with progressive dyspnea over 6 months. PFTs show FVC 62%, DLCO 38%, FEV1/FVC 0.82. Right heart catheterization reveals mPAP 28 mmHg, PCWP 12 mmHg, PVR 3.2 WU. Chest HRCT shows no significant ILD. Which of the following best characterizes his pulmonary hemodynamic profile?

Answer: Borderline mPAP not meeting criteria for pulmonary hypertension

Per the updated 2022 ESC/ERS guidelines, the threshold for pulmonary hypertension was lowered to mPAP >20 mmHg (from >25 mmHg). However, to classify as Group 1 PAH, the criteria require mPAP >20 mmHg AND PCWP ≤15 mmHg AND PVR ≥2 WU. While this patient meets mPAP >20 and PCWP ≤15, his PVR of 3.2 WU does meet criteria — but critically, his mPAP of 28 mmHg IS above 20 mmHg. Re-evaluating: mPAP 28 > 20, PCWP 12 ≤ 15, PVR 3.2 ≥ 2 WU — this IS pre-capillary PH meeting Group 1 PAH criteria under 2022 guidelines. However, note that the 'borderline' category (mPAP 21–24 mmHg) is a distinct entity requiring exercise testing. At mPAP 28, this patient meets full pre-capillary PAH criteria in the setting of systemic sclerosis (SSc-PAH, Group 1). The correct answer is A — pre-capillary PH consistent with Group 1 PAH, given mPAP >20, PCWP ≤15, and PVR ≥2 WU with an underlying connective tissue disease.

A 44-year-old woman is evaluated for recurrent hemoptysis. CT chest shows bilateral hilar lymphadenopathy and a 1.2 cm endobronchial lesion in the right lower lobe bronchus. Bronchoscopy reveals a smooth, yellowish submucosal lesion. Biopsy shows nests of uniform cells with round nuclei, rare mitoses, and positive staining for chromogranin A, synaptophysin, and TTF-1. Which of the following is most accurate regarding her diagnosis?

Answer: Atypical carcinoid: defined by 2–10 mitoses/2mm² or necrosis, higher nodal metastasis rate than typical carcinoid

The biopsy findings — rare mitoses, chromogranin/synaptophysin positivity, TTF-1 positivity — are consistent with a pulmonary carcinoid tumor. The distinction between typical and atypical carcinoid is critical: typical carcinoid has 10 mitoses/2mm² and extensive necrosis. Answer D is wrong — TTF-1 does not distinguish these entities. B is the most accurate standalone statement.

A 67-year-old man with COPD (GOLD Stage 3, CAT score 22) has had 3 exacerbations in the past year despite triple therapy (LABA/LAMA/ICS). His eosinophil count is 180 cells/µL. He is a former smoker (40 pack-years) with no history of asthma. Which add-on therapy has the strongest evidence base for reducing exacerbation frequency in this specific patient?

Answer: Azithromycin 250 mg daily, particularly effective in non-current smokers with frequent exacerbations

Azithromycin 250 mg daily (or 500 mg three times weekly) has robust RCT evidence (ALBERT trial, COPD-AZ trial) for reducing exacerbations in COPD patients with frequent exacerbations, particularly in former or never-smokers. Critically, the benefit was NOT seen in current smokers in the ALBERT trial. Since this patient is a former smoker, azithromycin is strongly indicated. Roflumilast (answer A) is appropriate for chronic bronchitic phenotype with FEV1 <50% and frequent exacerbations — this patient qualifies, but azithromycin has broader and stronger evidence in this exact population. Dupilumab (answer B) received FDA approval for COPD with eosinophils ≥300 cells/µL — his count of 180 is below the approved threshold. Mepolizumab (answer D) was studied in METREX/METREO trials: only the METREX dose of 100 mg showed benefit, and primarily in patients with ≥300 eosinophils/µL — 180 cells/µL is below the validated threshold. Azithromycin is the most evidence-supported choice here.

A 29-year-old woman at 32 weeks gestation presents with acute onset pleuritic chest pain and dyspnea. Her Wells score for PE is 4 (clinical signs of DVT present, heart rate 108, no alternative diagnosis). CT pulmonary angiography reveals a right lower lobe segmental PE. Which of the following anticoagulation strategies is most appropriate?

Answer: Low molecular weight heparin (LMWH) throughout pregnancy and for at least 6 weeks postpartum (minimum 3 months total)

LMWH is the anticoagulant of choice for VTE in pregnancy. It does not cross the placenta, has predictable pharmacokinetics, and has a well-established safety profile. The recommended duration is throughout the remainder of pregnancy AND for at least 6 weeks postpartum, with a minimum total treatment duration of 3 months (per ACOG, ASH, and CHEST guidelines). Answer A (UFH throughout) is second-line, used primarily near delivery or in patients with renal failure. Answer B is incorrect because warfarin crosses the placenta and is teratogenic in the first trimester and associated with fetal hemorrhage — it is contraindicated in pregnancy (though it can be used postpartum while breastfeeding). Answer D is incorrect because direct oral anticoagulants (DOACs) including rivaroxaban are contraindicated in pregnancy due to placental transfer and lack of safety data; animal studies suggest teratogenicity.

A 52-year-old man is admitted with community-acquired pneumonia requiring ICU-level care. Despite appropriate antibiotics for 72 hours, he develops worsening hypoxemia. ABG on FiO2 0.7, PEEP 12 cmH2O shows PaO2 58 mmHg (P/F ratio 83). He meets Berlin criteria for severe ARDS. The intensivist initiates prone positioning. Which of the following physiologic mechanisms MOST explains the survival benefit of prone positioning in severe ARDS?

Answer: Reduction in transpulmonary pressure gradient by redistributing pleural pressure more homogeneously, reducing ventilator-induced lung injury

The primary survival benefit of prone positioning in severe ARDS (demonstrated in the PROSEVA trial, 28-day mortality 16% vs 32.8%) is reduction of ventilator-induced lung injury (VILI). In the supine position, there is a steep pleural pressure gradient from ventral to dorsal regions, causing overdistension of ventral alveoli and collapse/atelectasis of dorsal alveoli — creating heterogeneous strain and stress risers. Proning homogenizes the pleural pressure gradient across lung regions, reducing regional overdistension and collapse cycling (the mechanism of VILI). While answer B is also correct (prone positioning does recruit posterior lung zones and improves V/Q matching), this explains the oxygenation benefit, NOT the survival benefit — patients can achieve similar oxygenation improvements with high PEEP supine without a mortality benefit. The PROSEVA trial showed mortality benefit even after controlling for oxygenation response. The survival benefit is specifically attributable to VILI reduction through more homogeneous stress distribution, making A the most accurate mechanistic explanation for the mortality benefit.

A 61-year-old woman with a 25 pack-year smoking history (quit 8 years ago) undergoes low-dose CT lung cancer screening. The scan reveals a 7 mm pure ground-glass nodule (GGN) in the right upper lobe. No solid component is identified. Which of the following management strategies is most consistent with current Lung-RADS and Fleischner Society guidelines for this finding?

Answer: CT follow-up at 6 months to assess for interval growth or development of a solid component

Per Fleischner Society 2017 guidelines for incidental pulmonary nodules and Lung-RADS 2022 for screening-detected nodules, a pure ground-glass nodule (GGN) of 7 mm in a screening patient (high-risk by definition) is categorized as Lung-RADS 3 (probable benign) and warrants 6-month CT follow-up. The rationale: pure GGNs grow slowly and represent adenocarcinoma spectrum lesions (AIS, MIA, or invasive adenocarcinoma). PET-CT (answer B) is inappropriate — pure GGNs are typically FDG-negative even when malignant due to their indolent metabolic activity, making PET non-diagnostic. Answer C (3 and 5 year follow-up) is appropriate for GGNs <6 mm in low-risk patients per Fleischner (or for GGNs ≥6 mm in low-risk patients per some protocols), but in a screening context with a 7 mm GGN, 6-month follow-up per Lung-RADS takes precedence. Answer D (surgical resection) is not indicated without evidence of growth or solid component development — pure GGNs have a protracted natural history and immediate resection would represent overtreatment.