Pulmonology Flashcards

A 58-year-old woman with systemic sclerosis presents with progressive dyspnea over 6 months. PFTs show FVC 62%, DLCO 38% predicted, FEV1/FVC ratio 0.82. Right heart catheterization reveals mPAP 28 mmHg, PCWP 10 mmHg, PVR 3.2 Wood units. Six-minute walk distance is 310 meters. Which of the following best describes her hemodynamic classification and the most appropriate next step?

Answer: Pre-capillary pulmonary hypertension (Group 3); optimize treatment of underlying ILD before adding PAH-specific therapy

This patient has SSc-associated ILD with PH. Per updated 2022 ESC/ERS guidelines, mPAP 28 mmHg with PVR ≥2 Wood units qualifies as pre-capillary PH. However, in the context of significant ILD (FVC <70% and markedly reduced DLCO), she fits Group 3 PH (due to lung disease), not Group 1 PAH. The priority is optimizing ILD treatment (e.g., nintedanib or mycophenolate) before layering PAH-specific vasodilators, which can worsen ventilation-perfusion mismatch in ILD-dominant disease. Initiating Group 1 PAH combination therapy without addressing ILD could be harmful.

A 44-year-old never-smoker is found to have a 22 mm solid pulmonary nodule on CT performed after a motor vehicle accident. PET scan shows SUV max of 2.8 in the nodule. Bronchoscopy with BAL and transbronchial biopsy is non-diagnostic. CT-guided biopsy reveals scattered atypical lymphoid cells. Flow cytometry on the biopsy sample is pending. Which feature would MOST strongly argue against primary pulmonary MALT lymphoma and instead favor a reactive process?

Answer: Polyclonal kappa and lambda light chain expression on flow cytometry

Primary pulmonary MALT lymphoma (extranodal marginal zone lymphoma) is characterized by a monoclonal B-cell proliferation, typically CD20+/CD5-/CD10-, with lymphoepithelial lesions on histology. A low PET SUV is characteristic of low-grade MALT lymphoma and does not distinguish it from reactive disease. Polyclonal kappa and lambda light chain expression on flow cytometry is the hallmark of a reactive (non-neoplastic) lymphoid proliferation, as malignant B-cell clones demonstrate light chain restriction (monoclonality). This finding would most strongly argue against lymphoma.

A 67-year-old man with GOLD Stage III COPD (FEV1 38% predicted) is admitted for a moderate exacerbation. He is on triple inhaled therapy (LAMA/LABA/ICS). Arterial blood gas on admission: pH 7.32, PaCO2 58 mmHg, PaO2 54 mmHg, HCO3 29 mEq/L. He is started on high-flow nasal cannula at 40 L/min, FiO2 0.40. After 90 minutes, repeat ABG: pH 7.30, PaCO2 64 mmHg, PaO2 88 mmHg. He remains alert and cooperative. What is the most appropriate next intervention?

Answer: Initiate non-invasive positive pressure ventilation (NIV/BiPAP)

This patient has acute hypercapnic respiratory failure with worsening respiratory acidosis (pH 7.30, PaCO2 64) despite HFNC. NIV (BiPAP) is the indicated next step for COPD exacerbations with hypercapnic failure (pH 7.25–7.35) and is supported by strong evidence to reduce intubation rates and mortality. HFNC has not been shown to be equivalent to NIV in hypercapnic COPD exacerbations. While the PaO2 improved with HFNC, the rising PaCO2 and worsening acidosis indicate ventilatory failure requiring pressure support. Intubation is premature in an alert, cooperative patient who has not yet failed NIV. Reducing FiO2 alone will not address the ventilatory failure.

A 35-year-old woman with no prior pulmonary history presents with recurrent hemoptysis and is found to have bilateral ground-glass opacities on HRCT. Urinalysis shows 3+ hematuria with red cell casts. Serum creatinine is 2.4 mg/dL (baseline unknown). Anti-GBM antibody is positive. ANCA is also positive (PR3-ANCA). She is initiated on plasmapheresis and immunosuppression. Which of the following statements about her dual-positive serology is MOST accurate?

Answer: Dual-positive patients have a higher risk of relapse than single anti-GBM positive patients and may require prolonged immunosuppression beyond anti-GBM clearance

Dual anti-GBM/ANCA positivity occurs in approximately 30% of anti-GBM disease cases and carries a distinct clinical phenotype. These patients tend to have the severe, acute presentation of anti-GBM disease (rapidly progressive GN, pulmonary hemorrhage) but also the relapsing course of ANCA vasculitis. Unlike isolated anti-GBM disease (which rarely relapses once antibody clears), dual-positive patients have a higher relapse risk driven by the ANCA component and may need prolonged immunosuppression. ESRD rates are similar to or worse than anti-GBM alone, not better. This is not a laboratory artifact — the association is well-established.

A 52-year-old man with a 35 pack-year smoking history presents with a 3 cm right upper lobe mass. CT-PET shows hypermetabolic activity in the mass (SUV 12) and a single ipsilateral mediastinal node at station 4R (SUV 4.1). Endobronchial ultrasound-guided biopsy (EBUS) of station 4R is performed and cytology shows no malignant cells. Pulmonary function is adequate for resection. What is the most appropriate next step?

Answer: Mediastinoscopy to further sample station 4R before any surgical resection

A PET-positive mediastinal node with a negative EBUS creates a discordant result. Per ACCP and ESTS guidelines, a PET-positive node that is EBUS/EUS-negative requires surgical staging (mediastinoscopy or VATS) before proceeding to resection, because false-negative EBUS rates can reach 20–30% in this scenario. Proceeding directly to resection risks incomplete staging and potentially leaving behind N2 disease that would change the treatment plan. Mediastinoscopy remains the gold standard for confirming or excluding N2 disease when less invasive methods are negative in the setting of a PET-positive node. Chemoradiotherapy without confirmed N2 disease would be premature.

A 29-year-old woman with obesity (BMI 41) and no other comorbidities presents with excessive daytime sleepiness, morning headaches, and bilateral papilledema on fundoscopic exam. Polysomnography shows AHI 52 events/hour, mean SaO2 88%, with prolonged periods of hypoventilation. Arterial blood gas while awake shows pH 7.37, PaCO2 52 mmHg, PaO2 62 mmHg, HCO3 30 mEq/L. Serum bicarbonate elevation is consistent with chronic compensation. Which diagnostic criterion BEST supports a diagnosis of Obesity Hypoventilation Syndrome (OHS) rather than OSA with nocturnal hypoventilation alone?

Answer: Awake daytime hypercapnia (PaCO2 ≥45 mmHg) in the absence of other causes of hypoventilation

The cardinal diagnostic criterion for Obesity Hypoventilation Syndrome (OHS) is awake daytime hypercapnia (PaCO2 ≥45 mmHg) in an obese patient (BMI ≥30) after excluding other causes of hypoventilation (e.g., COPD, neuromuscular disease, chest wall deformity, hypothyroidism). This patient's awake PaCO2 of 52 mmHg with elevated bicarbonate confirms chronic daytime CO2 retention. OSA alone — even with severe nocturnal desaturation — does not cause daytime hypercapnia in the absence of impaired ventilatory control. The AHI, nocturnal SaO2 nadir, BMI threshold, and ESS score are not diagnostic of OHS; they suggest OSA but cannot distinguish it from OHS without the daytime gas exchange criterion.